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IEEE 802.3 Repeater
1993 Advanced Micro Devices, Inc. Advanced Micro Devices reserves right make changes products without notice order improve design performance characteristics.
This publication neither states implies warranty kind, including limited implied warrants merchantability fitness particular application. AMD® assumes responsibility circuitry other than circuitry product. information this publication believed accurate respects time publication, subject change without notice. assumes responsibility errors omissions, disclaims responsibility consequences resulting from information included herein. Additionally, assumes responsibility functioning undescribed features parameters.
Trademarks
registered trademarks Advanced Micro Devices, Inc. IMR, IMR+, HIMIB, TPEX TPEX+ trademarks Advanced Micro Devices, Inc. Product names used this publication identification purposes only trademarks their respective companies.
TABLE CONTENTS
Section Section Section 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 Section Section
Technology Overview Terminology/Definition Overview Applications Overview Standards
Repeater Management Standards IEEE 802.3 Repeater Management IEEE 802.3 Management Novell's Management Interface (HMI) IETF Managed Objects IEEE 802.3 Repeaters 2-13 IMR/IMR+ Overview Functional Description IMR/IMR+ Based "Velcro Hub" Design Port Activity Monitor (PAM) Operation Link Test State Machine Description Receive Polarity Detection/Correction Algorithm Alternate Reconnection Algorithm Interaction Between Port Disable Port Autopartition IMR/IMR+ Management Port 3-10 IMR+ Device Repeater State Machine Description 3-15 Response Preamble Only 3-17 Response Shrinkage 3-17 Designing Repeaters Using Multiple IMR+ Devices 3-18 Expansion Port 3-19 External Arbiter 3-20 Reset Circuitry 3-20 Differences Between IMR+ Devices 3-22 IMR/IMR+ Propagation Delays 3-24 HIMIB Overview Architectural Overview HIMIB/IMR+ Chip-Set Management Capabilities HIMIB Device Hardware Design Considerations HIMIB Device Software Design Considerations
Managed Repeater Design High Level Design Considerations Managed Repeaters Fixed Port Repeater Design IMR+/HIMIB Interface AUI/MAC Interface Expansion Bus/MAC Interface HIMIB Device Microprocessor Interface 5-11 Managed Repeater Status Indicators 5-13 Modular Repeater Collision Arbitration 5-14
Table Contents
Section Section Appendix
Layout Recommendations Attachment Unit Interface Decoupling Power Planes Filter Modules
Glossary
10BASE-T Interface Filter Transformer Modules Isolation Transformers
Table Contents
SECTION
TECHNOLOGY OVERVIEW
TERMINOLOGY/DEFINITION
Computer networks allow computer systems stations share information. network consists communications medium (typically cable plant), network transmission devices assist communication. physical cable plant generally configured either star topology. topology stations into single cable that runs from station next. star topology stations connected central point, where network repeater connects cable segments together. star topology offers major advantages. first advantage that computer network merged with existing building telephone network. telephone traditionally configured star topology, single integrated cable plant results lower costs easier cable management. second advantage star networks that repeater convenient point monitoring managing network. Some station failures result stations transmitting endlessly network. topology this would disrupt entire network. star topology, repeater unit detect fault isolate that station from network. network remains operational available other stations. access method rules that stations control when they access network. Ethernet access method Carrier Sense, Multiple Access with Collision Detect, CSMA/CD. This means that before station transmits, monitors network activity. waits detects that another station already transmitting. Once network available, station free transmit. While transmitting, stations monitor network collisions with other stations, that more than station transmitting same time. When station detects collision ceases transmit, then after variable amount time attempts transmit once again. large degree access method determines kind needed star topology cableplant. CSMA/CD based concept that station transmissions broadcast complete network, that fact determine when there collision. simplest Ethernet networks could have been passive star, where each segment passively coupled rest segments. However this would result significant loss signal strength, high network error rates. this reason 10BASE-T network hubs active repeaters. These repeaters regenerate received signal broadcast rest network. Additionally, Ethernet repeater must perform collision detection each attached links. Repeaters perform these essential tasks:
Repeaters regenerate received signal comply with IEEE 802.3 specifications
prior retransmitting links.
Repeaters detect propagate collisions stations. finally repeaters exclude (partition) stations from network under certain fault
conditions. repeater market broken down into four product categories. following sections describe different categories, along with their main functional characteristics.
Technology Overview
OVERVIEW APPLICATIONS
years since development IEEE 802.3 10BASE-T standard, 10BASE-T repeaters have evolved into diverse classes products. These products characterized different numbers ports, modularity, reliability, manageability, different costs. This section describes four categories IEEE 802.3 Repeater products, their essential characteristics.
1.2.1
Fixed Configuration Unmanaged Repeaters
Unmanaged repeaters perform only basic IEEE 802.3 functions. These devices vary configuration from ports. They adhere strategy monitor LED, manage disconnect, that they provide port status error information through visual indicators only. They provide facility remote monitoring control, although they provide simple local connection (RS232) connect computer terminal basic maintenance.
Figure
Fixed Configuration Unmanaged Repeater
17314A-1
advantage these devices been their cost. They achieved this cost eliminating essential capabilities, manageability modularity. Manageability historically been costly implement, resulting significantly higher product cost. Modularity allows repeaters support variable port configurations. However modular repeaters require higher initial cost system chassis, which then amortized across many more ports.
Technology Overview
1.2.2
Fixed Configuration Managed Repeaters
Figure shows network using managed repeater. This repeater allows remote management station monitor control operation.
Figure
Fixed Configuration Managed Repeater
Management
17314A-2
term "management" means that repeater supports access information regarding operation. Managed 10BASE-T repeaters differ exactly what information available, that information accessed. recently completed IEEE 802.3 Repeater Management standard defines common sets information required managed IEEE 802.3 repeaters. Most managed 10BASE-T repeaters support modes remote access. In-band access allows remote management stations manage repeater through repeater network. Out-of-band access allows remote management through separate interface, such serial port. Local management capabilities allow access management information through local interface, such front panel switches, LED's, attached terminal. Remote management uses management protocol transmit management information between repeater remote management station. This simple serial terminal interface modem access, network management protocol such Simple Network Management Protocol (SNMP). Fixed configuration managed repeaters have recently been extended support system level modularity. Known "rack stack" repeaters, these devices combine flexibility modular repeater with cost fixed configuration repeater. This product essentially fixed configuration repeater, with additional external interface connect other repeaters. external interface used allow these devices concert single repeater. Some these products allow single "master" unit manage other "slave" units through management interface, resulting additional cost savings.
Technology Overview
1.2.3
Modular (Enterprise) Repeaters
Modular repeaters used environments where potential need exists large number ports. combining repeaters into single system chassis, modular repeaters take advantage shared costs such power supply network management module. These systems have high initial cost increased size power requirements, however they offer easy expansion installing additional port modules.
Figure
Modular Repeaters
Management
17314A-3
These systems also support enhanced capabilities, such redundant power supplies support multiple segments. Multiple segment support allows card card segmentation network busy networks. These modular hubs often provide bridging routing between segments, well support different media access protocols (Token Ring, FDDI etc.), different media types (STP, UTP, Coax, Fiber Optics). This class system generally deployed large building campus networks. these environments network reliability major concern. that reason this class repeater almost always includes network management capabilities. That capability reflected higher initial cost these systems.
1.2.4
Server Based Repeaters
Server based repeaters class 10BASE-T product. These repeaters consist more cards designed installed file server itself. many cases, file servers located near 10BASE-T repeaters. File servers already have chassis, power supply, processor capable managing repeater. these environments, where file server slots available more repeater cards, this provides cost option.
Technology Overview
Figure Unmanaged Server-Based Repeaters
17314A-4
Initially server based repeaters provided only unmanaged capabilities. These products equivalent fixed configuration dumb repeater. Newer server based repeaters capabilities server processor management support these products. Novell, Inc. recently introduced Management Interface (HMI) specification. This specification provides hardware independent interface between Novell Netware server management software repeater (hub) card.
Figure Managed Server-Based Repeaters
Management
17314A-5
Technology Overview
HIMIB IMR+ repeater chipset directly supports additional management requirements server based repeaters. offers design called ISA-HUBTM-KT managed server applications. This design provides complete hardware software solution server based managed repeater applications. complete user manual ISA-HUB available from (PID #17642A).
OVERVIEW STANDARDS
Computer networking standards developed several different standards bodies with overlapping jurisdiction. Ethernet repeaters defined standards three different organizations. three organizations Institute Electrical Electronic Engineers (IEEE), International Standards Organization (ISO), Internet Engineering Task Force (IETF). IEEE 802.3 committee defined core Ethernet standard. This work involved original coax repeater specifications, newer 10BASE-T specification, various IEEE 802.3 management specifications. IEEE standards ultimately submitted International Standards Organization (ISO) final approval international standard. This straight forward process basic physical layer media access specifications. However network management specification split between IEEE. developed standards specification management information. IEEE 802.3 committee used this basis their work specification repeater management. Additionally IEEE 802.1 committee specified management information required repeaters IEEE protocol suite. These standards work together specify requirements IEEE 802.3 Repeater Management. What specified these standards protocol transport network management information over network. most widely supported network management protocol Simple Network Management Protocol (SNMP). Internet Engineering Task Force (IETF), organization responsible development guidelines administration U.S. based Internet, specified SNMP. IETF organization ties into world standards organization through Department Defense, entity separate from IEEE ANSI. What important that IETF specifies management information will represented when transmitted over network. Specifically IETF defined IEEE 802.3 Repeater Management Information Base (MIB) that used transmit repeater information through network. This based work IEEE 802.3 Repeater Management task group. final specification interest Management Interface specification developed Novell, Inc. This interface specification that describes what management information must supported IEEE 802.3 cards Novell file servers, that information passed Novell management protocol stack. This specification based early draft version IEEE 802.3 Repeater Management standard, additional requirements beyond published IEEE 802.3 specification.
1.3.1
IEEE 802.3 Repeater Standard
original IEEE 802.3 standards defined coax cable transmission network information between many stations single network segment. distance network maximum number stations attached network were limited signal loss coax cable. IEEE 802.3 then developed Section standard, detailing repeater extend distance number stations that could attached single IEEE 802.3 network. repeater regenerated electrical signal retimed transmitted bits, connecting coax segment another. standard supports extended network topology where stations separated many repeaters.
Technology Overview
segments attached repeaters part same collision domain, meaning that CSMA/CD access method extends through repeaters over entire network. round trip delay time must limited maximum collision window defined core IEEE 802.3 standard. total size this network limited need sense collisions between stations opposite ends network. Where IEEE 802.3 coax repeater standard allows connection multiple stations through coax segment, IEEE 802.3 10BASE-T standard transmission Ethernet over Unshielded Twisted Pair (UTP) cable requires that repeater port attached each individual 10BASE-T station. effective implementing this with multiport 10BASE-T repeater, which provides multiple 10BASE-T station ports. Each 10BASE-T link meters long, consists twisted pairs conductors total) cable. pair used transmit, receive. 10BASE-T repeaters 802.3 network still constrained IEEE 802.3 limitation most repeaters between stations. Where coax based IEEE 802.3 stations physically attached same cable, 10BASE-T stations physically attached individual cables called "link segments". However 10BASE-T repeater makes them appear connected single cable. does this propagating incoming frames from station other stations network, well detecting signaling when collision condition detected. repeater receives frames from attached station, propagates rest attached stations. During propagation frame, repeater regenerates signal, retimes bits. Each repeater clock recovery circuit that enables receive decode (separate clock from data) incoming stream. When repeater detects incoming frame port, connects that port clock recovery circuit where frame then decoded. decoded bits passed into small FIFO, from which they retransmitted ports using repeater's locally generated clock. This process removes clock jitter restores signal level incoming frame. initial bits frame lost this process because clock recovery circuit requires times synchronize with incoming data. Subsequent frames come from different stations, each with different clock source. This means that repeater clock recovery circuit must able synchronize different clock source each frame. repeater also plays central role collision detection propagation. Collision detected monitoring activity ports. When more incoming ports active simultaneously, when repeater detects receive mode collision port, signals collision condition transmitting signal ports. This logically identical collision behavior coax based IEEE 802.3 network, with exception that collision detection repeater quicker easier than collision detection method used stations coax IEEE 802.3 networks.
1.3.2
IEEE 802.3 Repeater Management
IEEE 802.3 committee working define management requirements IEEE 802.3 networks. This work initially resulted Section "Layer Management" standard, more recently Section "Layer Management 10Mb/s Baseband Repeaters" standard. IEEE 802.3 Repeater Management specification defines what managed inside repeater, repeater managed network manager. individual entities inside repeater that managed referred management objects. These objects fall into three basic classes.
Attributes
Attributes accessible pieces information repeater. They provide status information about operational state repeater network, such
Technology Overview
health repeater, number collisions, total number received bytes, etc. Attributes readable, writable, both. case IEEE 802.3 Repeater Management standard, attributes read only.
Actions
Actions commands that network manager direct repeater execute. They allow manager alter state value management object, such resetting repeater, enabling disabling ports, etc.
Notifications
Notifications messages repeater required send network manager when significant event occurs. Unlike attributes actions that originate network manager, notifications originate repeater itself. Because their potential impact available network bandwidth, these messages only used report significant events. IEEE 802.3 management objects relate repeater hierarchical manner. Some objects support management overall repeater. Others used manage individual ports repeater. port repeater would then require these objects each port. Individual groups ports also assigned several objects support management cluster ports single entity. single repeater could then have groups, each consisting ports total ports. IEEE 802.3 management objects grouped into three sets, packages. Packages each consist number attributes, actions notifications. three packages defined IEEE 802.3 Repeater Management Basic Control, Performance Monitoring, Address Tracking. Basic Control required minimum objects that must supported managed IEEE repeaters. Performance Monitoring optional management objects necessary monitor performance IEEE 802.3 repeaters. These objects consist many real-time port repeater statistics. Support these objects provided HIMIB chip. Address tracking provides port level detection attached station addresses. Like Performance Monitoring package, Address Tracking package requires statistics supported HIMIB device.
1.3.3
IEEE 802.3 Management
most recent element IEEE 802.3 architecture undergo management standardization Media Attachment Unit (MAU). IEEE 802.3 actual physical line interface. Using management, network manager determine status information initiate control actions MAU. Each port managed repeater subject support IEEE 802.3 Management requirements. Like IEEE 802.3 Repeater Management suite, IEEE 802.3 Management standard organized several packages. Basic Control provides minimum mandantory requirements managed MAUs. Control enables network manager control well monitor operation. Media Loss conditional attribute that provides optional support attachments. Broadband final conditional package, providing optional support broadband network management.
1.3.4
Simple Network Management Protocol
IEEE 802.3 suite management standards specifies management objects required support standard interoperable management IEEE 802.3 systems. does address issue this information communicated remote manager. Simple Network Management Protocol (SNMP) many network manage-
Technology Overview
ment protocols. Because origins TCP/IP networking community SNMP widely used complex heterogeneous corporate networks. basic function SNMP provide protocol "get" "set" management information base (MIB) attributes remote stations, remote station signal "alarm" condition network manager. Using this capability network managers monitor (get) control (set) remote station operation. IEEE 802.3 notification supported SNMP alarm message. IEEE 802.3 Repeater, SNMP allows network managers enable disable ports, well acquire frame error performance statistics. SNMP protocol specified Request Comments (RFC) 1157.
1.3.5
MIB-I, MIB-II, Repeater RMON
Along with network management protocol (SNMP), network management requires standard addressing specific attributes. This structure network objects referred containment tree, consists hierarchy management object classes. IEEE 802.3 repeater ports addressed individually part group. groups combined into repeater, which turn part station. station could turn contain additional repeaters other manageable objects. IETF defined MIB-I (RFC 1156) original specification management objects stations SNMP network. These objects dealt primarily with network interfaces elements protocol stack. MIB-II (RFC 1213) modified these object definitions, extending them cover other related objects. Neither MIB-I MIB-II defined support repeater management objects. IETF Repeater (RFC 1368) developed based IEEE 802.3 Repeater Management standard. describes SNMP based management attributes required repeater management objects. These MIBs generally oriented toward management network management stations within local campus network. amount traffic actively monitor station operation excessive standards, however because bandwidth limitations remote monitoring more difficult. Because this specification remote management over wide area network defined. This allows remote network monitoring station report general network information back central management station. Only when requested central management station would detailed traffic information transmitted between remote monitor central manager. specification remote network monitoring management information base referred RMON MIB. This specifies broad selection optional management monitoring capabilities, allowing vendors craft RMON products which span broad range applications cost. While directly related IEEE 802.3 Repeater Management, many RMON (RFC 1271) attributes mimic those defined IEEE 802.3 management suite. 10BASE-T repeaters often appropriate devices host remote management engine, could have RMON capabilities installed option.
Technology Overview
1-10
Technology Overview
SECTION
REPEATER MANAGEMENT STANDARDS
IEEE 802.3 REPEATER MANAGEMENT
This section describes IEEE 802.3 Repeater Management Information Base (MIB). IEEE 802.3 repeater consists several different object types. From implementation point view important ones attributes, actions, notifications. Attributes used monitor control device operation. Actions force repeater execute management command, while notifications used repeater signal network manager that significant event occurred. following sections list three management packages, their management objects. IEEE 802.3 objects grouped into three packages, known Basic Control package, Performance Monitoring package, Address Tracking package. Repeater management objects fall into three main classes. "repeater" object class contains those objects necessary overall repeater management. "group" object class contains objects necessary manage collections ports. Ports clustered into groups easier manageability, "group" attributes provide observability into those groups. group frequently used denote characteristics physical implementation, such port card which fits into modular chassis. "port" object class contains objects that used manage operation individual ports repeater group.
2.1.1
Basic Control Package (Mandatory)
Table lists attribute, action, notification management objects IEEE 802.3 Repeater Management Basic Control package. These management objects primarily concerned with repeater configuration information repeater status (health). Following table brief description management object. Because Basic Control package objects require high speed event tracking, they typically implemented software. exact specification these other objects refer actual standard documents.
Repeater Management Standards
Table IEEE 802.3 Repeater Basic Capabilities Package Repeater Class Repeater Repeater Repeater Repeater Repeater Repeater Repeater Repeater Repeater Repeater Repeater ResourceTypeID ResourceTypeID Group Group Group Group Port Port Port Port Object Name repeaterID repeaterGroupCapacity groupMap repeaterHealthState repeaterHealthText repeaterHealthData resetRepeater executeNonDisruptiveSelfTest repeaterHealth repeaterReset groupMapChange resourceTypeIDName resourceInfo groupID groupPortCapacity portMap portMapChange portID portAdminState autoPartitionState portAdminControl Object Type Attribute Attribute Attribute Attribute Attribute Attribute Action Action Notification Notification Notification Attribute Attribute Attribute Attribute Attribute Notification Attribute Attribute Attribute Action Ref. Para 19.2.3.2 19.2.3.2 19.2.3.2 19.2.3.2 19.2.3.2 19.2.3.2 19.2.3.3 19.2.3.3 19.2.3.4 19.2.3.4 19.2.3.4 19.2.5.2 19.2.5.2 19.2.5.2 19.2.5.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.3
repeaterID
"repeaterID" read-only attribute used identify specific instance repeater system. consists integer value between 1024.
repeaterGroupCapacity
"repeaterGroupCapacity" read-only attribute used identify maximum number groups supported this repeater. consists integer value between 1024. "repeaterGroupCapacity" larger than actual number installed groups.
groupMap
"groupMap" read-only attribute used identify actual installed groups this repeater. consists a-bit string "repeaterGroupCapacity" bits length. Each-bit signals absence ("0") presence ("1") group, numbered from lowest highest.
repeaterHealthState
"repeaterHealthState" read-only attribute used indicate general health repeater. consists numeric value. possible values are: other repeaterFailure groupFailure portFailure generalFailure undefined unknown known failures known have repeater-related failure known have group-related failure known have port-related failure unspecified failure type
event that multiple failures present, highest priority failure (lowest numbered failure) should reported.
Repeater Management Standards
repeaterHealthText
"repeaterHealthText" read-only attribute, consisting text string that provides relevant information about operational state repeater network manager. contents this attribute vendor specific, used provide detailed failure information problem resolution instructions. string must printable text longer than characters length.
repeaterHealthData
"repeaterHealthData" read-only attribute consisting block information related operational state repeater. encoding information vendor specific, must exceed bytes length.
resetRepeater
"resetRepeater" action. When received, repeater state reset "Start" state defined IEEE 802.3 Section standard. This forces repeater execute disruptive self-test. exact requirements self test unspecified. repeater maintains management information throughout execution this action, transmits "repeaterReset" notification response this action request. During this action repeater must inject packets onto segment. Received packets transferred implementors discretion.
executeNonDisruptiveSelfTest
"executeNonDisruptiveSelfTest" action. When received, repeater executes vendor specific test. During test state repeater unchanged, management information remains intact. This test must inject packets onto segment attached repeater. This test does interfere with transfer packets through repeater. Completion this test results "repeaterHealth" notification.
repeaterHealth
"repeaterHealth" notification. sent when health state repeater changes, including initial powering repeater. minimum repeaterHealth notification consists "repeaterHealthState" attribute. optionally includes "repeaterHealthText" "repeaterHealthData" attributes.
repeaterReset
"repeaterReset" notification. sent when repeater reset power-up, upon completion resetRepeater action. repeaterReset notification contains repeaterHealthState, optionally repeaterHealthText repeaterHealthData attributes.
groupMapChange
"groupMapChange" notification that group been logically inserted removed from repeater. This notification sent during repeater power This notification consists groupMap attribute.
resourceTypeIDName
"resourceTypeIDName" read-only attribute. used contain name resourceTypeID managed object, fixed value "RTID". 802.1F Common Definitions Procedures IEEE Management Information (Draft) additional details.
resourceInfo
"resourceInfo" read-only attribute provided repeater manufacturer. used describe resource. attribute contains ManufacturerOUI (Organizational Unit Identifier), ManufacturerName, ManufacturerProductName, ManufacturerProductVersion. 802.1F Common Definitions Procedures IEEE Management Information (Draft) additional details.
Repeater Management Standards
groupID
"groupID" read-only attribute used identify specific instance group class repeater. integer value range 1024. This value cannot exceed "repeaterGroupCapacity".
groupPortCapacity
"groupPortCapacity" read-only attribute used identify number potential ports this instance group. integer value range 1024. number actual ports present less than equal groupPortCapacity.
portMap
"portMap" read-only attribute used identify actual installed ports this group. consists a-bit string "groupPortCapacity" bits length. Each-bit signals absence ("0") presence ("1") port, numbered from lowest highest.
portMapChange
"portMapChange" notification that port been logically inserted removed from group. This notification sent during repeater power This notification consists portMap attribute.
portID
"portID" read-only attribute used identify specific instance port group. consists integer value between 1024.
portAdminState
"portAdminState" read-only attribute used indicate whether port currently enabled disabled. disabled port does transmit receive. This attribute preserved across repeater reset loss power. This attribute writable, however controlled through portAdminControl action. This attribute takes precedence over auto-partition mechanism. value means port disabled, value means enabled.
autoPartitionState
"autoPartitionState" read-only attribute indicating state port autoPartition state machine. value means that port currently auto partitioned, value means that port currently auto partitioned.
portAdminControl
"portAdminControl" action. When received modifies "portAdminState" attribute. used enable port, while used disable port. disabled port does transmit receive information. transition from disabled enabled "portAdminState" causes auto partition state machine return `BEGIN' state, defined Section IEEE 802.3 standard.
2.1.2
Performance Monitoring Package (Optional)
performance monitoring package provides additional statistics beyond those provided basic control capabilities package. These statistics consist multiple 32-bit counters each port, which fully supported HIMIB. Prior introduction HIMIB these management objects required extensive hardware software support.
Repeater Management Standards
Table IEEE 802.3 Performance Monitoring Package Repeater Class Repeater Port Port Port Port Port Port Port Port Port Port Port Port Object Name transmitCollisions readableFrames readableOctets frameCheckSequenceErrors alignmentErrors framesTooLong shortEvents runts collisions lateEvents veryLongEvents dataRateMismatches autoPartitions Object Type Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Ref. Para. 19.2.3.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2 19.2.6.2
transmitCollisions
"transmitCollisions" read-only attribute that counts number transmit collisions this repeater detected. value transmitCollisions attribute 32-bit counter with minimum rollover time hours.
readableFrames
"readableFrames" read-only attribute that counts number valid frames detected port. Valid frames from bytes 1518 bytes length, have valid frame received without collision. This attribute 32-bit counter with minimum rollover time hours.
readableOctets
"readableOctets" read-only attribute that counts number total octets received each port. This number determined adding frame length this register completion every valid frame. This attribute 32-bit counter with minimum rollover time minutes.
frameCheckSequenceErrors
"frameCheckSequenceErrors" read-only attribute that counts number frames detected each port with invalid frame check sequence. This counter incremented each frame valid length bytes 1518 bytes) that does suffer collision during frame. This counter incremented each invalid frame, however incremented frames with both framing errors frame check sequence errors. This attribute 32-bit counter with minimum rollover time hours.
alignmentErrors
"alignmentErrors" read-only attribute that counts number frames detected each port with error framing error. Frames that have both framing errors errors counted this attribute, frameCheckSequenceErrors attribute. This attribute 32-bit counter with minimum rollover time hours.
framesTooLong
"framesTooLong" read-only attribute that counts number frames that exceed 1518 byte maximum frame size. This attribute 32-bit counter with minimum rollover time days.
Repeater Management Standards
shortEvents
"shortEvents" read-only attribute that counts number instances where activity detected with duration less than "ShortEventMaxTime" (74-82-bit times). This attribute 32-bit counter with minimum rollover time hours.
runts
"runts" read-only attribute that counts number instances where activity detected with duration greater than "ShortEventMaxTime" (74-82-bit times), less than minimum valid frame time (512-bit times, bytes). This attribute 32-bit counter with minimum rollover time hours.
collisions
"collisions" read-only attribute that counts number instances where carrier detected port, collision detected. This attribute 32-bit counter with minimum rollover time hours.
lateEvents
"lateEvents" read-only attribute that counts number instances where collision detected after LateEventThreshold (480-565-bit times) frame. This event will counted both "lateEvents" attribute, well "collisions" attribute. This attribute 32-bit counter with minimum rollover time hours.
veryLongEvents
"veryLongEvents" read-only attribute that counts number times transmitter active greater than Jabber Lockup Protection Timer allows ms-7.5 ms). This attribute 32-bit counter with minimum rollover time days.
dataRateMismatches
"dataRateMismatches" read-only attribute that counts number occurrences where frequency, data rate incoming signal detectably different from local transmit frequency. This attribute 32-bit counter that incremented each such event.
autoPartitions
"autoPartitions" read-only attribute that counts number instances where repeater partitioned this port from network. This attribute 32-bit counter that incremented each such event.
2.1.3
Address Tracking Package (Optional)
address tracking package provides optional information related address frames received each port. This information used monitor attached station addresses port port basis. objects Address Tracking package directly supported HIMIB.
Table
IEEE 802.3 Address Tracking Package Repeater Class Port Port lastSourceAddress Object Name lastSourceAddress sourceAddressChanges Object Type Attribute Attribute Ref. Para. 19.2.6.2 19.2.6.2
"lastSourceAddress" read-only attribute that saves value Source Address field last frame received. This attribute 6-byte field.
Repeater Management Standards
sourceAddressChanges
"sourceAddressChanges" read-only attribute that counts number times source address field received frames changes. This attribute 32-bit counter with minimum rollover hours.
IEEE 802.3 MANAGEMENT
Section IEEE 802.3 standard defines management requirements Media Attachment Unit (MAU). Table defines management objects specified IEEE 802.3 Section This standard draft form time this document written, objects change. objects been assigned numbers time this written. Refer draft document detailed descriptions object definitions. Like IEEE 802.3 Repeater Management Standard, IEEE 802.3 Management Draft consists several packages. Basic package minimum subset required managed MAU. Control package optional package that provides management control operation. Media Loss Tracking package (actually attribute) mandatory package AUI's that keeps statistics media availability. Media Loss Tracking package optional other MAU's. Finally, Broadband package required management objects broadband MAU's.
Table
IEEE 802.3 Management Package Basic Basic Basic Basic Basic Basic Control Control Media Loss Tracking Broadband Broadband Object Name mauID mauType mauMediaAvailable jabber mauAdminState jabber resetMAU mauAdminCtrl mauLoseMediaCounter bBandSplitType bBandFrequencies Object Type attribute attribute attribute attribute attribute notification action action attribute attribute attribute Reference 20.2.3.2 20.2.3.2 20.2.3.2 20.2.3.2 20.2.3.2 20.2.3.4 20.2.3.3 20.2.3.3 20.2.3.2 20.2.3.2 20.2.3.2
mauID
"mauID" read-only attribute used identify specific instance port. consists integer value.
mauType
"mauType" read-only attribute used identify IEEE 802.3 type. This consists integer value, that section number where specific type specified.
mauMediaAvailable
"mauMediaAvailable" read-only attribute used signal status media link. link based MAU's such 10BASE-T this link test fail state. other MAU's such basic interface this loopback detection status.
mauLoseMediaCounter
"mauLoseMediaCounter" read-only attribute used count number times mauMediaAvailable attribute gone from`available' other state. This counter must allowed increment rate greater than times second.
Repeater Management Standards
jabber
"jabber" part attribute consisting jabberFlag, jabberCounter. Both parts attribute read-only. jabber Counter attribute counts number times jabberFlag enters `fault' state. This counter must allowed increment rate greater than times second.
mauAdminState
"mauAdminState" read-only attribute used indicate current control status MAU, that what state manager previously commanded assume. Refer mauAdminCtrl state definitions.
bBandSplitType
"bBandSplitType" read-only attribute used monitor configuration broadband IEEE 802.3 MAU. This attribute indicates whether broadband cabling system single cable system dual cable system.
bBandFrequencies
"bBandFrequencies" part integer used broadband IEEE 802.3 consisting Transmitter Carrier Frequency Translation Offset Frequency. Transmitter Carrier Frequency part attribute actual transmitter carrier frequency divided KHz. Likewise Translation Offset Frequency part attribute translation offset frequency divided KHz.
resetMAU
"resetMAU" action that results performing reset. This reset must least second length, during which should idle. This reset should operate same power reset.
mauAdminCtrl
"mauAdminCtrl" action that controls operational state MAU.
jabber
"jabber" notification that detected jabber fault. This same condition that determines state jabber attribute (jabberFlag).
NOVELL'S MANAGEMENT INTERFACE (HMI)
Novell Inc. defined Management Interface (HMI) specification. Supporting IEEE 802.3 cards Novell file servers, this specification defines hardware independent driver requirements managed third party card vendors. This document specifically focuses support 10BASE-T repeaters, rather than supporting IEEE 802.3 repeaters general. interface consists components. first definition objects accessible through "get" "set" commands from management protocol layers. second specification memory structure used communicate between driver protocol stack. different memory structures defined, Interface Table (HIT), Group Interface Table (GIT). IEEE 802.3 managed objects split into groups. Part objects managed using capabilities HMI. Others accessed through variables GIT. specification developed during draft stages IEEE 802.3 Repeater Management specification, differs number managed objects.
Note that following IEEE 802.3 Repeater Management objects have equivalence: repeaterID, resourceInfo, groupID, portMap, portMapChange, portID. Additionally offers only very limited support newly developed Management specification.
Repeater Management Standards
2.3.1
Novell HMI/IEEE 802.3 Repeater Mapping
Table provides summary management objects, their IEEE 802.3 equivalents. text following table provides overview objects previously described 802.3 Repeater Management section. more detailed information refer Novell specification. Novell management attributes divided into four classes. first three mimic IEEE 802.3 Repeater Management definitions, with Basic Control, Performance Monitoring, Address Tracking packages. fourth called Novell Extensions, includes additional management attributes.
Table
IEEE 802.3 Management Object Equivalencies Object Package Basic Basic Basic Basic Basic Basic Performance Performance Performance Performance Performance Performance Performance Performance Performance Performance Performance Performance Performance Performance Address Address Novell Novell Novell Object Name InfoTablePointer ResetHubAction ExecutesSelfTest1Action ExecutesSelfTest2Action PortAdminState AutoPartitionState TransmitCollisions RepeaterVeryLongEvents PortVeryLongEvents ReadableFrames ReadableOctets FrameCheckSequenceErrors AlignmentErrors FramesTooLong ShortEvents Runts Collisions LateEvents DataRateMismatches AutoPartitions LastSourceAddress SourceAddressChanges PortLinkState RepeaterTotalOctets PortType IEEE Object Name resetRepeater executeNonDisruptive SelfTestAction portAdminState autoPartitionState transmitCollisions veryLongEvents readableFrames readableOctets frameCheckSequenceErrors alignmentErrors framesTooLong shortEvents runts collisions lateEvents dataRateMismatches autoPartitions lastSourceAddress sourceAddressChanges aMediaAvailable (MAU Mgmt)
InfoTablePointer
"InfoTablePointer" pointer Information Table (HIT). This pointer used access other management information.
ExecuteSelfTest1Action
"ExecuteSelfTest1Action" equivalent 802.3 Repeater Management "executeNonDisruptiveSelfTest" action.
Repeater Management Standards
ExecuteSelfTest2Action
"ExecuteSelfTest2Action" action that causes repeater perform disruptive self test. This test interfere with transfer packets through repeater.
PortAdminState
This management object consists IEEE 802.3 objects. Both operations available this object. operation corresponds IEEE 802.3 portAdminControl action, while operation corresponds IEEE 802.3 portAdminState management attribute.
RepeaterVeryLongEvents
This management attribute tracks number VeryLongEvents repeater seen ports. This attribute IEEE 802.3 veryLongEvents attribute across ports repeater.
PortLinkState
This management attribute Novell vendor specific extension basic IEEE 802.3 management attributes. It's purpose track port port basis whether port receiving link status pulses. This attribute consists integer value from with following meaning: Link Link Down Applicable port 10BASE-T port.
RepeaterTotalOctets
This management attribute Novell vendor specific extension basic IEEE management attributes. This attribute counts total number bytes repeated hub, whether frame valid not. This counter adds bytes frame preamble.
PortType
This management attribute Novell vendor specific extension basic IEEE management attributes. This attribute number from with following meanings: Other port type Normal port type Local host port port
2.3.2
Information Table (HIT)
Table describes structure Information Table (HIT). Several variables table represent IEEE 802.3 repeater management attributes, passed through table instead through managed object requests.
2-10
Repeater Management Standards
Table Information Table Object Name Reserved HubType Reserved1 MajorVersion MinorVersion ManufacturerID Reserved2 HubDescriptionPointer HubVersionPointer HealthState HealthTextPointer HealthDataPointer HealthDataLength GroupsSupported GroupInfoTablePointer CapabilitiesBitMap Table Offset (hex bytes) IEEE Object Name
resourceTypeIDName
repeaterHealthState repeaterHealthText repeaterHealthData repeaterGroupCapacity
Most entries this table have IEEE 802.3 equivalents. following brief description these parameters. Refer specification more details.
Reserved
This 16-byte reserved field.
HubType
This 1-byte field signify that this 10BASE-T hub.
Reserved1
This 1-byte reserved field.
MajorVersion
This field major version number. version number this table `1'.
MinorVersion
This field minor version number. current number this table `0'.
ManufacturerID
This 3-byte manufacturer's field, specified IEEE 802.1F Recommended Practice draft document. IEEE 802.1F equivalent attribute resourceInfo typically three leading bytes manufacturer's address.
Reserved2
This 1-byte reserved field.
HubDescriptionPointer
This field points text string describing this hub.
HubVersionPointer
This field points text string that describes hub's version number.
HealthDataLength
This length bytes preceding HealthDataPointer. Because HealthData string contains binary information, cannot terminated `0'.
Repeater Management Standards 2-11
GroupInfoTablePointer
This 4-byte pointer Group Information Table (GIT).
CapabilitiesBitMap
This field 1-byte value indicating level management capabilities present this managed HUB. These numbers range from with following meanings: Basic Control Performance Monitoring Address Tracking Novell Extensions
2.3.3
Group Information Table (GIT)
Table group information table. used provide information related specific groups ports Repeater. Several IEEE 802.3 attributes passed through Group Information Table instead being transferred managed objects.
Table
Group Information Table Object Name Installed Slot Ports Description ObjectIDPointer ObjectIDLength InstalledTime DriverWorkspace
IEEE Object Name groupMap groupPortCapacity
Slot
This optional 1-byte field indicate slot number selected Group.
Description
This 4-byte pointer text string indicating information about this group.
ObjectIDPointer
This 4-byte pointer array 16-bit words, that provides manufacturer's group identification information. format this information documented "Structure Identification Management Information TCP/IP based Internets" enterprise subtree. This provides exact specification class group being managed.
ObjectIDLength
This 2-byte value length Object array bytes.
InstalledTime
This 4-byte field system time when group last installed hub.
DriverWorkspace
This 10-byte field available driver temporary storage during it's execution.
2-12
Repeater Management Standards
2.3.4
Notifications
addition managed objects, attributes passed through GIT, Novell document specifies various events Repeater cause notification message passed manager. Table lists notification messages required specification. These notifications correspond their IEEE 802.3 equivalents.
Table
Notifications Object Name HealthChange GroupChange HubReset IEEE 802.3 Object Name repeaterHealth groupMapChange repeaterReset
IETF MANAGED OBJECTS IEEE 802.3 REPEATERS
IEEE 802.3 committee defined repeater management objects, IETF extended definition specify protocol encoding remote management these objects. IETF also defined additional objects managing repeaters. actual definition syntax these objects defined 1368, "Definitions Managed Objects IEEE 802.3 Repeater Devices". Table lists IETF 802.3 Repeater `get' `set' attributes, cross references IEEE 802.3 Repeater Management attributes actions. Refer 1368 detailed description each management object. Many SNMP managed objects have corresponding analog IEEE 802.3 repeater MIB.
Table
SNMP IEEE 802.3 Attribute Cross-reference IETF Identification Code snmpDot3RptrMgt.1.1.1 snmpDot3RptrMgt.1.1.2 snmpDot3RptrMgt.1.1.3 snmpDot3RptrMgt.1.1.4 snmpDot3RptrMgt.1.1.5 snmpDot3RptrMgt.1.1.6 snmpDot3RptrMgt.1.2.1.1.1 snmpDot3RptrMgt.1.2.1.1.2 snmpDot3RptrMgt.1.2.1.1.3 snmpDot3RptrMgt.1.2.1.1.4 snmpDot3RptrMgt.1.2.1.1.5 snmpDot3RptrMgt.1.2.1.1.6 snmpDot3RptrMgt.1.3.1.1.1 snmpDot3RptrMgt.1.3.1.1.2 snmpDot3RptrMgt.1.3.1.1.3 snmpDot3RptrMgt.1.3.1.1.4 snmpDot3RptrMgt.1.3.1.1.5 IETF 802.3 Repeater Reference rptrGroupCapacity rptrOperStatus rptrHealthText rptrReset rptrNonDisruptTest rptrTotalPartitionedPorts rptrGroupIndex rptrGroupDescr rptrGroupEntry rptrGroupOperStatus rptrGroupLastOperStatusChange rptrGroupPortCapacity rptrPortGroupIndex rptrPortIndex rptrPortAdminStatus rptrPortAutoPartitionState rptrPortOperStatus IEEE 802.3 Repeater Reference repeaterGroupCapacity repeaterHealthState repeaterHealthText resetRepeater executeNonDisruptiveSelf TestAction groupID
groupPortCapacity portID portAdminState portAdminControl autoPartitionState
Repeater Management Standards
2-13
Table SNMP IEEE 802.3 Attribute Cross-reference (continued) IETF Identification Code snmpDot3RptrMgt.2.1.1 snmpDot3RptrMgt.2.2.1.1.1 snmpDot3RptrMgt.2.2.1.1.2 snmpDot3RptrMgt.2.2.1.1.3 snmpDot3RptrMgt.2.2.1.1.4 snmpDot3RptrMgt.2.3.1.1.1 snmpDot3RptrMgt.2.3.1.1.2 snmpDot3RptrMgt.2.3.1.1.3 snmpDot3RptrMgt.2.3.1.1.4 snmpDot3RptrMgt.2.3.1.1.5 snmpDot3RptrMgt.2.3.1.1.6 snmpDot3RptrMgt.2.3.1.1.7 snmpDot3RptrMgt.2.3.1.1.8 snmpDot3RptrMgt.2.3.1.1.9 snmpDot3RptrMgt.2.3.1.1.10 snmpDot3RptrMgt.2.3.1.1.11 snmpDot3RptrMgt.2.3.1.1.12 snmpDot3RptrMgt.2.3.1.1.13 snmpDot3RptrMgt.2.3.1.1.14 snmpDot3RptrMgt.2.3.1.1.15 snmpDot3RptrMgt.3.1.1.1.1 snmpDot3RptrMgt.3.1.1.1.2 snmpDot3RptrMgt.3.1.1.1.3 snmpDot3RptrMgt.3.1.1.1.4 snmpDot3RptrMgt.3.2 snmpDot3RptrMgt.3.3 IETF 802.3 Repeater Reference rptrMonitorTransmitCollisions rptrMonitorGroupIndex rptrMonitorGroupTotalFrames rptrMonitorGroupTotalOctets rptrMonitorGroupTotalErrors rptrMonitorPortGroupIndex rptrMonitorPortIndex rptrMonitorPortReadableFrames rptrMonitorPortReadableOctets rptrMonitorPortFCSErrors rptrMonitorPortAlignmentErrors rptrMonitorPortFrameTooLongs rptrMonitorPortShortEvents rptrMonitorPortRunts rptrMonitorPortCollisions rptrMonitorPortLateEvents rptrMonitorPortVeryLongEvents rptrMonitorPortDataRate Mismatches rptrMonitorPortAutoPartitions rptrMonitorPortTotalErrors rptrAddrTrackGroupIndex rptrAddrTrackPortIndex rptrAddrTrackLastSourceAddress rptrAddrTrackSourceAddrChanges rptrAddrTrackGroupInfo rptrAddrTrackPortInfo IEEE 802.3 Repeater Reference transmitCollisions
portID readableFrames readableOctets frameCheckSequenceErrors alignmentErrors framesTooLong shortEvents runts collisions lateEvents veryLongEvents dataRateMismatches autoPartitions
portID lastSourceAddress sourceAddressChanges
Table 2-10 lists IETF traps, which correspond IEEE management notifications objects.
Table 2-10 SNMP Trap IEEE 802.3 Notification Cross-Reference IETF Identification Code snmpDot3RptrMgt.1 snmpDot3RptrMgt.2 snmpDot3RptrMgt.3 IETF 802.3 Repeater Reference rptrHealth rptrGroupChange rptrResetEvent IEEE 802.3 Repeater Reference repeaterHealth groupMapChange repeaterReset
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Repeater Management Standards
SECTION
IMR/IMR+ OVERVIEW
FUNCTIONAL DESCRIPTION
Am79C981 Integrated Multiport Repeater Plus device single chip implementation IEEE 802.3/Ethernet repeater hub). addition eight integral 10BASE-T ports plus port comprising basic repeater, IMR+ chip also provides hooks necessary complex network management diagnostics. IMR+ device also expandable, enabling implementation high port count repeaters based several IMR+ devices. IMR+ device interfaces directly with AMD's Am79C987 Hardware Implemented Management Information Base (HIMIB) device allow fully managed multiport repeater implemented specified IEEE 802.3 Layer Management Mb/s Baseband Repeaters Standard. When IMR+ HIMIB devices used chip set, HIMIB device maintains complete repeater port statistics which accessed demand microprocessor through simple 8-bit parallel port.
Figure
IMR+ Block Diagram
Management Port
Repeater State Machine
Expansion Port
Twisted Pair Port
Twisted Pair Port
17314A-6
IMR+ device differs from original chip only minor internal details. IMR+ device pin, software timing compatible with device, used direct replacement existing IMR-based design. Most enhancements IMR+ device relate provision additional internal status information, which primarily included companion HIMIB device. HIMIB device requires this enhanced status information order allow implementation fully managed repeater, compliant IEEE 802.3 Layer Management Mb/s Baseband Repeaters Standard. implementation managed repeaters covered detail Section this manual, complete definition changes between
IMR/IMR+ Overview
IMR+ devices contained this section under "Differences Between IMR+ Devices". From perspective simple cost, unmanaged repeater application, primary additional feature offered IMR+ device over above that original device, provision "Minimum Mode", designed minimize external support logic provide simple diagnostic status related indicators (LEDs). Minimum Mode explained more detail this section under "Minimum Mode Operation".
IMR/IMR+ BASED "VELCROHUB" DESIGN
systems, combined with power supply, crystal EMI/RFI filter/transformer modules, effectively produces fully operational 10BASE-T repeater, with port allow connection existing 10BASE2/5 coax backbone.
Figure
Simple "VelcroHub" Example
Power Supply Regulator Isolation IMR/IMR+ Status LEDs
Quad Filter/ Transformer Module
Quad Filter/ Transformer Module
17314A-7
3.2.1
IMR-Based "VelcroHub" Design
"Velcro Hub" application example shown Figure 3-3. external connects Management Port device, implements simple state machine. This used configure programmable options device power default options need changed), then continuously clocks Management Port "Get" requests pin. also clocks results obtain internal status information (such Link Status, Partitioning Polarity). result "Get" request, output device, shifted into external serial-to-parallel converter, used drive status indicators, using simple pulse stretch driver circuit. state machine enhanced allow external selection (through front panel mounted switch other selection mechanism) different Management Port "Get" requests, such that same LEDs used display various status information. "IMR VelcroHub Board" available from example design kit, which details these concepts.
IMR/IMR+ Overview
Figure "Velcro Hub" Design Using Device
SCLK
Port
State Machine (PAL)
Am79C980
Port
Port
8-Bit SIPO Shift Register Driver
SHIFT SERIN
0.01%
17314A-8
Link Test Status LEDs
Note: Unused receiver pairs +/-, +/-, RXDn +/-) should shorted together.
3.2.2
IMR+ Based "Velcro Hub" Design
design simple repeater using IMR+ device simplified "Minimum Mode", which allows status information continuously output from Management Port IMR+ device, without need external state machine. Figure shows application example employing IMR+ device Minimum Mode.
Figure
"Velcro" Design Using IMR+ Device
XTAL
Am79C981 IMR+ Chip
SIPO
ASYNC RESET TEST
Register
SCLK
17314A-9
IMR/IMR+ Overview
this configuration, IMR+ device will continuously output four status conditions pin, dependent programming TEST pins. programming TEST allows following status indications reported Port Loop Back Status (1-bit) Twisted Pair Port Link Status (8-bits) AUI/Twisted Pair Port Partitioning Status (9-bits) Port Test Error Status (1-bit) Twisted Pair Polarity Status (8-bits) AUI/Twisted Pair Port Rate Error Status (9-bits) state TEST pins changed time select alternative status pin. data output 10-bit serial stream (AUI status first, followed status, status, etc.). blank period will occur after status bits have been output, during which time will active, delineating start/end each "status window". output stream directly input serial-toparallel convertor, used drive status indicators using appropriate latches drivers. details programming timing Minimum Mode covered following section. Since data presented valid only "status window" individual bit, such Loop Back Error, active only ns), external pulse stretch circuitry should included ensure that indicators visible. Note that normal "Get" "Set" capabilities IMR+ Management Port unavailable when Minimum Mode selected.
3.2.3
Minimum Mode Operation
IMR+ Minimum Mode supports designs end, unmanaged repeaters. This mode uses minimal additional support logic display following status indicators:
Port Loop Back Status Twisted Pair Port Link Status AUI/Twisted Pair Port Partitioning Status Port Test Error Status Twisted Pair Port Receiver Polarity Status AUI/Twisted Pair Port Rate Error Status
Additionally Minimum Mode IMR+ chip supports automatic receive polarity detection/correction without addition external logic. IMR+ device determines that Minimum Mode selected monitoring state TEST while asserted. TEST HIGH (asserted), while reset active (RST LOW) enters Minimum Mode. Additionally state during reset determines IMR+ device programmed Automatic Polarity Detection/ Correction. TEST input must deasserted rising edge reset. maximum delay allowed account propagation delay. TEST Function Normal Management Mode Normal Management Mode Minimum Mode, Receive Polarity Detection/Correction disabled. Minimum Mode, Receive Polarity Detection/Correction enabled.
IMR/IMR+ Overview
Minimum Mode, used serially output IMR+ chip's status information based state SCLK pins: SCLK Output Port Test Error Status Port Receive Polarity Status Rate Error Status (All ports) Port Loop Back Status Ports Link Status Partitioning Status (All ports)
output format timing identical that when IMR+ device used stand alone mode (see Figure 3-5).
Figure
Management Port Minimum Mode Port Activity Monitor Signal Relationship
(Note
(Note
(Note
Notes: Externally generated signal illustrates internal IMR+ chip clock phase relationship. timing with C-bit cleared (IMR+ Chip Programmable Options) Minimum Mode
17314A-10
When outputs related status bits (Loop Back Error Test Error, depending value SCLK), followed status bits (receive polarity Link Status, depending value SCLK). status bits output order from port port When Port Partitioning Status Port Rate Error Status indicators output (depending value SCLK). output first, followed port indicators starting with port timing output matches that Port Activity Monitor (PAM). state SCLK pins checked every cycle after port status indicators have been output. rising edge clock, occurring before falling edge STR, used strobe state SCLK pins. IMR+ device programmed into Minimum Mode only reset, cannot modified until subsequent reset.
IMR/IMR+ Overview
PORT ACTIVITY MONITOR (PAM) OPERATION
IMR+ device pins, STR, used serially output state internal Carrier Sense signals from eight twisted pair ports. This function together with external hardware software used monitor repeater receive collision activity. accuracy signals Times (BT) µs). transition active state internal carrier sense bits that lasts less than 10BT latched internally used appropriate during next sample period. Figure illustration timing port activity monitor.
3.3.1
Stand-Alone IMR/IMR+ Device (With Output)
Figure shows external hardware employed convert serial stream into parallel format suitable "receive activity" display. Note that since data presented valid only single period, fact that maximum Ethernet packet length only ~1.2 duration, external pulse stretch circuitry should included ensure that indicators visible.
Figure
Port Activity Monitor
XTAL
Shift Register SIPO
ASYNC RESET
IMR/IMR+
Register
Carrier Sense Outputs
17314A-11
IMR/IMR+ Overview
Figure shows possible hardware implementation interface between IMR+ device some displays. should stressed that this only example, intended represent most cost-effective method implementing this function. This implementation also used display data output Minimum Mode.
Figure Example Implementation Port Activity Monitor Registers
SER/Q15 74LS673
17314A-12
SHCLK M/SCLK STRCLR
CRSTP7 CRSTP6 CRSTP5 CRSTP4 CRSTP3 CRSTP2 CRSTP1 CRSTP0 CRSAUI
3.3.2
IMR+ With HIMIB Device Output)
When IMR+ chip used with HIMIB device, IMR+ chip becomes input. Section under "Managed Repeater Status Indicators" details implement port activity monitor this case.
LINK TEST STATE MACHINE DESCRIPTION
link test function IMR+ devices implemented specified 10BASE-T Standard. During periods transmit pair inactivity, "Link Test" pulses will sent over twisted pair medium every ms-17 indicate medium integrity. When link test function enabled, absence Link Test pulses receive data RXD± pair IMR+ chip's 10BASE-T port will cause port into Link Fail state. Link Fail state, data transmission, data reception collision detection functions disabled, remain disabled until valid data consecutive Link Test pulses appear RXD± pair. During Link Fail, issuing command Link Test Status Ports using Management Port will return state port zero (cleared). When link identified functional, corresponding status will reported one. Note that case device, 10BASE-T port disabled, corresponding status will always returned "Link Pass". case IMR+ device, status link will reported accurately even port disabled. order inter-operate with systems which implement Link Test pulses, this function disabled issuing Disable Link Test Function command using
IMR/IMR+ Overview
IMR+ Management Port (with appropriate individual port identified within command). With link test disabled, data driver, receiver loopback functions well collision detection remain enabled irrespective presence absence data Link Test pulses RXD± pair. Note that IMR/IMR+ device will continue transmit Link Test pulses, regardless state Disable Link Test function, whether port disabled auto-partitioned. This ensures that opposite link segment will interoperate, regardless whether requires Link Test pulses not.
RECEIVE POLARITY DETECTION/CORRECTION ALGORITHM
IMR/IMR+ device receive function includes ability invert polarity signals appearing RXD± pair polarity received signal reversed (such case wiring error). This feature allows data packets received from reverse wired RXD± input pair corrected IMR/IMR+ device prior re-transmission twisted pair, Expansion Port interfaces. Following reset, polarity detection/correction function must explicitly enabled 10BASE-T ports. This accomplished issuing "Set" command Enable Automatic Receiver Polarity Reversal using IMR/IMR+ Management Port, programming IMR+ device into Minimum Mode. port with polarity detection/correction enabled which Link Fail state, will detect receive polarity based polarity subsequent packets with valid Transmit Delimiter (ETD). When Link Fail state, IMR+ device will recognize Link Test pulses positive polarity. Positive Link Test pulses defined received signal with positive amplitude greater than with pulse width ns-200 This positive excursion followed negative excursion. This definition consistent with expected received signal correctly wired receiver when Link Test pulse which fits template Figure 14-12 10BASE-T Standard generated transmitter passed through twisted pair cable. Negative Link Test pulses ignored. Exit from Link Fail state made reception four consecutive positive Link Test pulses, which spaced closer than 2.04 ms-4.1 (nominal) greater than 65.5 ms-131.1 apart. When IMR/IMR+ enters Link Pass state, polarity detection/correction algorithm will remain "armed" until consecutive packets with valid identical polarity detected. When "armed", receiver capable changing initial previous polarity configuration based most recent polarity. receipt first packet with valid following Link Fail, IMR+ device will utilize inferred polarity information configure RXD± input, regardless previous state. receipt second packet with valid with correct polarity, detection/correction algorithm will "lock-in" received polarity. second subsequent) packet detected confirming previous polarity decision, most recently detected polarity will used default. Note that packets with invalid have effect updating previous polarity decision. Once consecutive packets with valid have been received, IMR+ device will disable detection/correction algorithm until either Link Fail condition occurs port disabled re-enabled (when port forced into Link Fail) using Management Port. normal (correct) polarity detected port, issuing command Receive Polarity Status Ports using Management Port will return state port zero (cleared). reversed polarity been detected/corrected, corresponding status will reported one.
IMR/IMR+ Overview
ALTERNATE RECONNECTION ALGORITHM
port each ports partitioned when experiencing excessive frequency duration collisions. Excessive frequency collisions defined more than consecutive collisions single port. Excessive duration collision defined signal active more than 1024-bit times. Reconnection process whereby port returned operational status after partitioning. IMR+ device supports reconfiguration algorithms. standard IEEE 802.3 algorithm default algorithm, activated when IMR+ chip reset. This algorithm allows partitioned port reconnected able transmit receive data period times without experiencing collision. Alternate Reconnection Algorithm will reconnect partitioned port only port able transmit data period times without collision. This mode programmed through management port. Once Alternate Reconnection Algorithm programmed, IMR+ chip must hardware reset return default (standard 802.3) algorithm.
INTERACTION BETWEEN PORT DISABLE PORT AUTOPARTITION
Disabling port forces Autopartition State Machine that port into Idle State (Port Reconnected). Therefore, partitioned port reconnected first disabling then re-enabling port. This accordance with 802.3 Repeater Management Standard requirements.
IMR/IMR+ Overview
IMR/IMR+ MANAGEMENT PORT
Table lists Management Port command op-codes both IMR+ devices. Additionally, table lists command formats, response codes management `Get' commands. This section provides detailed description IMR+ device command op-codes.
Table
IMR/IMR+ Management Commands IMR/IMR+ IMR+ Only IMR/IMR+ IMR/IMR+ IMR/IMR+ IMR/IMR+ IMR/IMR+ IMR/IMR+ IMR/IMR+ IMR/IMR+ IMR/IMR+ IMR/IMR+ IMR+ Only IMR+ Only IMR+ Only IMR+ Only IMR/IMR+ IMR+ Only IMR/IMR+ IMR/IMR+ IMR+ Only IMR+ Only Command Code 0000 1CSA 0001 1111 0001 0000 0010 1111 0011 1111 0010 #### 0011 #### 0100 0### 0101 0### 0110 0### 0111 0### 1000 1111 1000 1011 1000 1101 1000 1001 1000 0000 1010 0000 1101 0000 1110 0000 1111 0000 1111 1111 1111 1111 1000 1111 PBSL 0000 PBSL 0000 PBSL 0000 PBSL 0000 M000 0000 XXXX 0000 XXXX 0001 P000 0000 Response (Get Only)
Command Type Command Description IMR+ Chip Programmable Options Alternate Port Partitioning Algorithm Alternate Port Partitioning Algorithm Port Disable Port Enable Port Disable Port Enable Disable Link Test Function (per port) Enable Link Test Function (per port) Disable Auto Polarity Correction (per port) Enable Auto Polarity Correction (per port) Port Status (BSL Cleared) Port Status Cleared) Port Status Cleared) Port Status (None Cleared) Port Partitioning Status Rate Error Status Ports Link Test Status Ports Receive Polarity Status Ports MJLP Status Version Port Status
3.8.1
Management Port
IMR+ device management functions enabled when TEST tied LOW. management commands byte oriented data input serially pin. responses generated during execution management command output serially byte-oriented format IMR+ device pin. Both input output data streams clocked with rising edge SCLK pin. serial command data stream associated results data stream structured manner similar RS232 serial data format, i.e., Start followed eight Data Bits. externally generated clock SCLK either free running clock synchronized input patterns series individual transitions meeting
3-10
IMR/IMR+ Overview
setup hold times with respect input pattern. latter method used, noted that SCLK clock transitions required proper execution management commands that produce data, that SCLK clock transitions needed execute management commands that produce data.
3.8.2
Management Commands
following section details operation each management command available IMR+ chip. cases, individual bits each command byte shown with left right. Data bytes received transmitted first last. Table summary management commands.
(Write) Opcodes
IMR+ Chip Programmable Options data: 0000 1CSA data: None
IMR+ Chip Programmable Options enabled (disabled) setting (resetting) appropriate command string. three programmable bits are: C-CI Reporting; S-AUI Test Mask, A-Alternative Port Activity Monitor (PAM) Function. These options enabled (disabled) setting (resetting) appropriate command string. When writing this register through Am79C987 HIMIB device, bits should changed (A=0, C=1).
C-CI Reporting
Setting this alters function pin. this mode, becomes input response AMD's Am79C987 HIMIB device. Upon deassertion RST, HIMIB automatically sets this following IMR+ device type detection. When this mode selected, output string format modified include carrier addition carrier). This occupies position immediately preceding string bits) output. Note that carrier gets asserted either signal pairs active.
S-AUI Test Mask
Setting this allows IMR+ chip ignore activity signal pair, during Test window following transmission port. This event occurs when attached Test option enabled, therefore generating burst activity following every transmission. This interpreted IMR+ device collision, causing IMR+ device generate full pattern. Although attached repeater required have Test function active, this common installation error, causing difficulty diagnosing network throughput problems. Test Window, defined IEEE 802.3 (Section 7.2.2.2.4), from 6-bit times 34-bit times (0.6 µs). This includes delay introduced AUI. activity that occurs outside this window ignored treated true collision. Note that enabling this function does prevent reporting this condition IMR+ device Port Status) since functions operate independently.
A-Alternative Port Activity Monitor (PAM) Function
Setting Alternative Port Activity Monitor Function allows function altered such that Carrier Sense data presented unmodified. default operation output (Carrier Sense stream) masked port either disabled partitioned. This does allow Repeater Management software sense activity segments times. ability monitor partitioned disabled ports allows fault tolerant features built into Repeater Management software.
IMR/IMR+ Overview 3-11
Alternate Port Partitioning Algorithm data: 00011111 data: None
port Partitioning/Reconnection scheme programmed alternate (transmit only) reconnection algorithm invoking this command. return back standard (transmit receive) reconnection algorithm, necessary reset IMR+ device. standard partitioning algorithm selected upon reset.
Alternate Ports Partitioning Algorithm data: 00010000 data: None
ports Partitioning/Reconnection scheme programmed alternate (transmit only) reconnection algorithm invoking this command. ports affected group this command. return ports back standard (transmit receive) reconnection algorithm, necessary reset IMR+ device. standard partitioning algorithm selected upon reset.
Port Disable data: data: 00101111 None
port will disabled upon receiving this command. Subsequently, IMR+ chip will ignore inputs (Carrier Sense SQE) appearing port will transmit data Sequence port. Issuing this command will also cause port have internal partitioning state machine forced idle state. Therefore, Partitioned Port reconnected first disabling then re-enabling port.
Port Enable data: data: 00111111 None
This command enables previously disabled port. Note that partitioned port reconnected first disabling (AUI Port Disable command) then re-enabling port with this command. ports enabled upon reset.
Port Disable data: data: 00100### None
(### port number) port designated command byte will disabled upon receiving this command. Subsequently, IMR+ device will ignore inputs appearing disabled port's receive pins will transmit data Sequence that port's transmit pins. Issuing this command will also cause port have partitioning state machine returned Idle State (Port Reconnected). Therefore, partitioned port reconnected first disabling then re-enabling port. disabled port will continue report correct Link Test Status.
3-12
IMR/IMR+ Overview
Port Enable data: data: 00110### None
(### port number) This command enables previously disabled port. Re-enabling disabled port causes port placed into Link Test Fail state. This ensures that packet fragments received port repeated rest network. Note that force port into Link Fail state and/or reconnect partitioned port, port should first disabled Port Disable command) then re-enabled with this command. ports enabled upon reset.
Disable Link Test Function Port data: 01000### data: None
(### port number) This command disables Link Test Function port designated command byte, i.e., port will longer disconnected Link Fail. port which Link Test Function disabled will continue transmit Link Test pulses. twisted pair port Link Test disabled, then reading Link Test Status indicates being Link Test Pass.
Enable Link Test Function Port data: 01010### data: None
(### port number) This command re-enables Link Test Function port designated command byte. This command executes only designated port Link Test Function disabled Disable Link Test Function command. Otherwise, command ignored. Link Test enabled upon reset.
Disable Automatic Receiver Polarity Reversal data: 01100### data: None
(### port number) This command disables Automatic Receiver Polarity Reversal Function port designated command byte. this function disabled port with reverse polarity (due wiring error), then port will fail Link Test reversed polarity Link Pulses. Link Test Function also disabled port, then received reversed polarity packets would repeated other network ports IMR+ chip inverted data. Automatic Polarity reversal disabled upon reset.
Enable Automatic Receiver Polarity Reversal data: 01110### data: None
(### port number) This command enables Automatic Receiver Polarity Reversal Function port designated command byte. enabled port, IMR+ chip will automatically invert polarity that port's receiver circuitry port detected having reversed polarity (due wiring error). After reversing receiver polarity, port could then receive subsequent (reverse polarity) packets correctly.
IMR/IMR+ Overview
3-13
(Read) Opcodes
Port Status data: data: 10001111 PBSL0000
combined status allows single instruction used monitoring port. four status bits reported are:
Partitioning Status. This port partitioned connected. Rate Error. This there been instance FIFO Overflow Underflow, caused data received port. This cleared when status read. Test Status. This Test detected IMR+ chip. This cleared when status read. attached repeater must have Test disabled. This even port disabled partitioned. Loop Back Error. attached required loopback data transmitted onto circuit. loopback carrier detected IMR+ device, then this report this condition. This cleared when status read. repeater this only indication broken missing MAU. Alternate Port Status data: 10001111 data: PBSL0000
There three further variations above command, allowing selective clearing combination bits. They primarily included HIMIB chip. These are: Alternative
data: data: 10001011 PBSL0000
cleared. cleared. Alternative
data: data: 10001101 PBSL0000
cleared. cleared. Alternative
data: data: 10001001 PBSL0000
None cleared.
Port Partitioning Status data: 10000000
data: P7.P0 port partitioned port connected
partitioning Status eight ports accessed this command. port disabled, reading partitioning status will indicate that connected.
Rate Error Status Ports data: 10100000
data: E7.E0 This allows single command used report Rate Error Status condition (FIFO Overflow Underflow) Twisted Pair ports. bits output pattern correspond each ports, with least significant corresponding port
3-14
IMR/IMR+ Overview
status port there been instance when data received from that port caused FIFO error. status bits stay until status read.
Link Test Status Ports data: 11010000
data: L7.L0
Port Link Test Fail
Port Link Test Pass
Link Test Status eight ports accessed this command. disabled port continues report correct Link Test Status. Re-enabling disabled port causes port placed into Link Test Fail state. This ensures that packet fragments received port repeated rest network.
Receive Polarity Status Ports data: 11100000
data: P7.P0
Port Polarity Correct
Port Polarity Reversed
status eight port polarities accessed with this command. IMR+ chip ability detect correct reversed polarity ports' RXD+/- pins. polarity detected reversed port, then IMR+ chip will appropriate this command's result byte only Polarity Reversal Function enabled that port.
MJLP Status data: 11110000
data: M00000000 Each IMR+ chip contains independent Jabber Lock Protection Timer. timer designed inhibit IMR+ device transmit function, been transmitting continuously more than 65536 Times. MJLP Status this happens. This remains only cleared when MJLP status read using this command.
Version data: 11111111
data: XXXX0001 This command (1111 1111) used determine device version. IMR+ chip responds pattern: XXXX 0001 chip (Am79C980) responds pattern: XXXX 0000
IMR+ DEVICE REPEATER STATE MACHINE DESCRIPTION
state diagram Figure describes relationship between IMR+ repeater state machine IMR+ Expansion Port. diagram similar IEEE 802.3 Repeater Unit State Diagram (see ISO/IEC 8802-3: 1990 ANSI/IEEE 802.3-1990 Edition, Figure 9-2). Each IMR+ device contains independent implementation state machine. When multiple IMR+ devices interconnected form single, high port count repeater, Expansion Port that keeps these state machines synchronized with each other.
IMR/IMR+ Overview
3-15
Figure
Power START BEGIN Datain(ANY_THIS_IMR) *Collin(ALL) :[N<== Port(Datain II)] SEND PREAMBLE PATTERN Collin(ANYXN) Out(ALLXN_THIS_IMR) Preamble Pattern 1010., note TT(ALLXN) DataRdy Collin(ALL) Datain(N) SEND ONES Collin(ANYXN) Out(ALLXN_THIS_IMR) TwoOnes TwoOnesSent Collin(ALL) Datain(N) Collin(ANYXN) SEND DATA Out(ALLXN_THIS_IMR) Data Data, Collin(N) (Datain(N) Collin(ALL) AllDataSent TT(ANYXN) Fifo Over/Underflow Datain(N) Collin(ALL) AllDataSent Collin(ANYXN) EXPANSION PORT RECEIVE Out(ALL_THIS_IMR) (from sourcing IMR) notes Collin(N) (Datain(N) Collin(ALL) SQE) Collin(N) IDLE Out(ALL_THIS_IMR) Idle Datain(ANY_XTHIS_IMR) Collin(ALL) Port(Datain II)] Collin(ONLY1) SQE:[N Port(Collin SQE)]
IMR+ Device State Machine
Collin(N) (Datain(N) Collin(ALL) SQE)
Collin(ANYXN)
Datain(N) Collin(ALL) TT(ALLXN) AllDataSent TRANSMIT COLLISION Out(ALL_THIS_IMR) Collin(ANY_THIS_IMR) else Collin(ALL_XTHIS_IMR) Collin(ANYXN_THIS_IMR) else notes Collin(ONLY1) TT(ALL) Port(Collin SQE)] PORT LEFT Out(ALLXM_THIS_IMR) Collin(ANY_THIS_IMR) else Collin(ALL_XTHIS_IMR) Collin(M_THIS_IMR) else notes WAIT Out(ALL_THIS_IMR) Idle StartTw1 note RECEIVE COLLISION Out(ALLXN_THIS_IMR) Collin(ANY_THIS_IMR) else Collin(ALL_XTHIS_IMR) Collin(N_THIS_IMR) else notes
Collin(ANYXN)
Collin(ALL) TT(ALL) Tw2Done
Datain(N) Collin(ALL) TT(ALLXN) Tw2Done
Collin(ANY) Tw1Done
Collin(ANYXM)
Datain(M) Collin(ALL) Tw2Done
17314A-13
3-16
IMR/IMR+ Overview
Referring Figure 3-8, upper each block contains name state. center refers output ports. lower describes state REQ, DAT, output pins IMR+ device with this state machine embedded. There several items keep mind when interpreting state diagram: When either high-impedance (ACK input (ACK meaning "ALL", "ANY", "ANYXN", "ANYXM", etc. refers repeater unit single repeater formed connecting multiple IMR+ devices together). meaning modified "_THIS_IMR" "_XTHIS_IMR" appended. "_THIS_IMR" refers IMR+ device serviced local state machine. i.e., "ANY_THIS_IMR" refers port this particular IMR+ device. "_XTHIS_IMR" refers IMR+ device except serviced state machine. i.e., "ALL_XTHIS_IMR" refers ports except ones this particular IMR+ device. implies Collin(ANYXN) Collin(ANYXM) SQE. implies Collin(ANYXN) Collin(ANYXM) SQE. implies Collin(N) Collin(ONLY1) SQE. implies Datain(ANY) Datain(N) state diagram would completely describe Expansion Port without following notes.
Notes: cycle prior DAT, being driven. other words, transitions from will driven until cycle after transition. Similarly, transition from multiple lines being driven (COL only line being driven (COL will driven until cycle after transition. When entering RECEIVE COLLISION state from state other than RECEIVE COLLISION EXPANSION PORT RECEIVE state, sourcing IMR+ device will guarantee cycle even Collin(ALL) Datain(N) Collin(ALL) before then even though Out( Jam. Note supersedes this. condition transition from EXPANSION PORT RECEIVE RECEIVE COLLISION state different than from SEND PREAMBLE PATTERN, SEND ONES, SEND DATA RECEIVE COLLISION. Collin(N) only from EXPANSION PORT RECEIVE RECEIVE COLLISION state. This done sensing hence this reason condition stated Note necessary. condition transition from EXPANSION PORT RECEIVE WAIT state different than from SEND DATA WAIT. TT(ALLXN) needed transition from EXPANSION PORT RECEIVE WAIT state. WAIT state, Tw1Done, Tw2Done implemented 10BASE-T transceivers repeater state machine.
3.10
RESPONSE PREAMBLE ONLY
96-bit preamble only packet will signaled receive collision expansion port tail IMR/IMR+ device transmission because packet start frame delimiter (SFD).
3.11
RESPONSE SHRINKAGE
packet reception which commences less than normal inter-packet (IPG) period (due shrinkage, effect carrier drop intermediate point transmission path), will still treated received packet IMR/IMR+ device. However, IMR/IMR+ chip requires 43-bit times Idle
IMR/IMR+ Overview 3-17
(maximum) after reception re-acquire home frequency guarantee accurate decoding received data subsequent packet. Thus second packet this sequence garbled IMR/IMR+ device this spacing maintained. Normal network components operation will cause shrinkage below 48-bits, will therefore problem either IMR+ devices.
3.12
DESIGNING REPEATERS USING MULTIPLE IMR+ DEVICES
Multiple IMR+ devices connected together form large repeaters either with without HIMIB device. Section discussion multiple IMR+ repeater design using IMR+ HIMIB devices. Figure below shows multiple IMR+ chip based design.
Figure
Multiple IMR+ Based Repeater
REQ2 REQ3 REQ1 ARBITER
transceivers needed buses exceed loading.
ASYNC RESET Note
Am79C981 IMR+ Chip
XTAL OSC.
Am79C981 IMR+ Chip
Am79C981
Note
Direction HIGH 17314A-14
IMR+ Chip
3-18
IMR/IMR+ Overview
3.13
EXPANSION PORT
IMR+ chip Expansion Port comprised five pins; bi-directional signals (DAT JAM), input signals (ACK COL), output signal (REQ). These signals used when multiple-IMR+ device repeater application employed. this configuration, IMR+ chips must clocked synchronously with common clock connected inputs IMR+ devices. Reset needs synchronized clock. IMR+ device expansion scheme allows multiple IMR+ chips single board repeater modular multiport repeater with backplane architecture. bidirectional which used transfer data between IMR+ devices multiple-IMR+ chip design. data sent over line format synchronized common clock. another bidirectional that used active IMR+ chip communicate internal status remaining (inactive) IMR+ devices. When asserted HIGH, indicates that active IMR+ device detected collision condition generating Sequence. During this time when asserted HIGH, line used indicate whether active IMR+ chip detecting collision port only more than port. When driven HIGH IMR+ chip (while asserted IMR+ chip), then active IMR+ device detecting collision condition port only. This `one-port-left' signaling necessary multiple-IMR+ device repeater function correctly single multiport repeater unit. IMR+ chip also signals `one port left' collision condition event runt packet collision fragment; this signal will continue expansion port cycle (100 before deasserting REQ. arbitration access bussed bi-directional signals (DAT JAM) provided output (REQ) inputs (ACK COL). IMR+ chip asserts indicate that active wishes drive pins. external arbiter senses lines from IMR+ devices asserts line when only IMR+ chip asserting line. more than IMR+ chip asserting line, arbiter must assert signal, indicating that more than IMR+ device active. More than active IMR+ device time constitutes collision condition, IMR+ devices notified this occurence line Expansion Port. Note that transition from multiple IMR+ devices arbitrating pins (with asserted, deasserted) condition when only IMR+ chip arbitrating pins (with asserted, deasserted) involves expansion port cycle (100 ns). During this transitional cycle, deasserted, asserted, pins driven. However, each IMR+ device will remain collision state (transmitting sequence) during this transitional cycle. subsequent expansion port cycles (REQ still asserted), IMR+ devices will return `master slaves' condition where only IMR+ device active (with collision) driving pins. understanding this sequence crucial non-IMR+ devices (such Ethernet controller) connected expansion bus. Specifically, last device back Expansion Port after multi-IMR+ chip collision must assert line until drops request Expansion Port.
IMR/IMR+ Overview
3-19
3.14
EXTERNAL ARBITER
simple arbitration scheme required when multiple IMR+ devices connected together increase total number repeater ports. arbiter should have input (REQ1.REQn) each IMR+ devices used, global outputs (COL ACK). This function easily implemented PAL® device, with following logic equations:
REQ1 REQ2 REQ3 .REQn REQ1 REQ2 REQ3 .REQn
REQ1 REQ2 REQ3 REQn (REQ1 REQ2 REQ3 REQn)
Above equations positive logic, i.e., variable true when asserted. single PALCE16V8 will perform arbitration function repeater based several IMR+ devices.
3.15
RESET CIRCUITRY
IMR+ device used without HIMIB device, connected other devices expansion bus, data presented pins used, then signal asynchronous clock. many cases however signal must synchronized this clock. Figure shows example where synchronization necessary, possible circuit accomplishing this function. asynch reset signal active low, supplied pushbutton, software, conventional resistor-capacitor-diode power reset circuit. signal generated this circuit should applied every IMR+ device associated logic system. There alternative scheme synchronizing with which useful systems where different IMR+ devices powered otherwise reset diiferent times (see Figure 3-10). This scheme used design "IMR Velcro Board". reset curcuitry consists push button switch, network, Schmitt-trigger inverter, flip-flop (Figure 3-10). large time constant value used ensures that reset pulse with greater than required minimum value tRST However, this also means that rise fall times signal will longer than desired. this reason, Schmitt-trigger inverter used buffer, "square asynchronous reset signal from network input synchronizing flip-flop. This synchronizing flip-flop clocked RESET_CLK, output used that synchronous, active low, signal. synchronous signal reasons. first prevent possible problems that might arise from asnchronous reset signal (i.e., IMR/IMR+ device peripheral chips recognizing reset different times). second, more important reason, that reset signal synchronized (RESET_CLK) forces IMR/ IMR+ devices connected expansion synchronized each other after reset cycle. implementation Figure recommends that, generating signal same phase device's internal clock signal, frequency divider flip-flop's input should connected reset signal which synchronized clock. This design uses, signal synchronization.
3-20
IMR/IMR+ Overview
reason this that, Figure intent generate signal which, after synchronized reset cycle, matches device's internal signal. contrast, Figure 3-10, designs signal affected reset free running. Synchronizing RESET forces chip's internal signal match board's signal signal after reset cycle. Because propagation delay flip-flop (tPD), reset cycle recognized IMR+ chip until clock cycle after rising edge (RESET_CLK). recognition reset corresponds with rising edge TCK, reesults same phase relationship between IMR+ device's internal board's TCK, case when circuit Figure used. large time constant (see above) network used asynchronous reset signal ensures that IMR+ chip will reset upon powert Therefore, IMR+ device will synchronized board's signal times. Note that signal local signal included expansion bus. When three units "IMR Velcro Board" connected together over expansion bus, each board it's reset signal synchronized inverse bus' clock signal. this way, expansion scheme "IMR Velcro Board" demonstrates "hot swapping" line cards expandable repeater accomplished.
Figure 3-10 Reset Circuitry
IN5400 ASYNC_RESET 74HCT14 ASYNC_RESET
74HCT14 RESET_CLK
74LS74
Oscillator Module
74LS74A
17314A-15
IMR/IMR+ Overview
3-21
3.16
DIFFERENCES BETWEEN IMR+ DEVICES
following sections list functions that have been added IMR+ device have been modified from original device. These enhancements address number issues, including interfacing HIMIB chip, improved timing specifications, enhanced standards support. description Management Port commands available IMR+ devices, this section under "IMR/IMR+ Management Port".
3.16.1
IMR+ Chip Programmable Options
This command available device. Three additional programming bits provided IMR+ device, follows:
Port Test Mask. Mask activity port from being repeated 10BASE-T ports Expansion Port. Alternative Port Activity Monitor (PAM) Function. Provides carrier sense activity PAM, regardless enable/disable state auto-partition state and/or 10BASE-T ports. reporting. Provides reporting circuit activity within stream. IMR+ device Data Sheet (PID# 17306) additional details.
this section "Management Commands, (Write) Opcodes" under "IMR/ IMR+ Management Port" additional details.
3.16.2
Port Status
original Port Status command available device, enhanced IMR+ chip provide three additional status bits. Hence single request used monitor performance aspects port. This command uses same op-code (10001111) original Port Status command device. following status returned from IMR+ device (see Table more detail):
Partitioning Status. Reports auto-partition condition port. Identical both IMR+ devices. Rate Error. Reports FIFO underrun/overrun frame received port. This available device, added IMR+ device. Test Status. Reports that transceiver connected port Test enabled. This available device, added IMR+ device. Loop Back Error. Reports that port exhibiting circuit circuit loopback path. This available device, added IMR+ device.
IMR+ device Data Sheet (PID# 17306) additional details. addition, three further versions (four versions total) this command provided, which allow various combinations bits cleared process reading status.
3.16.3
Rate Error Ports)
This command available device, added IMR+ device. Reports FIFO underrun/overrun frame received 10BASE-T ports.
3.16.4
MJLP Status
This command available device, added IMR+ device. Reports that Jabber Lockup Protection (MJLP) timer activated.
3-22
IMR/IMR+ Overview
3.16.5
Version
Version command used determine device version number. device response this command XXXX 0000 IMR+ device response this command XXXX 0001
3.16.6
Minimum Mode
This function available device, added IMR+ device. "IMR+ Based VelcroHub Design" "Minimum Mode" sections additional details.
3.16.7
FIFO Underflow/Overflow
device, FIFO over-run under-run condition forces device enter Transmit Collision State, causing transmission pattern ports, including receiving port. case IMR+ device, FIFO underflow/overflow error handled using Receive Collision State. this case, responsible port will observe pattern returned from IMR+ based repeater Rate Error will reported port). Since this error caused serious receive error condition (i.e., station transmitting frequency substantially outside allowable specification, transmission excessively long), treated Receive Collision.
3.16.8
3.16.8.1
Twisted Pair Link Integrity Status
Port Disable Link Test
device, when Twisted Pair port disabled, corresponding status reported "Link Pass", regardless condition Link Test state machine. IMR+ device, disabled port continues report accurate Link Test Status. Disabling enabled Twisted Pair port device, causes port forced into Link Fail state. Re-enabling disabled port IMR+ device, causes port forced into Link Fail state. This ensures that packet fragments received port repeated rest network.
3.16.8.2 Interaction Between Link Fail Port Autopartition.
device, Twisted Pair port which partitioned subsequently enters Link Fail state, will reconnected. IMR+ device, Twisted Pair port Receive Link Test State machine decoupled from Autopartition State Machine. Entering Link Fail state will cause partitioned port reconnected.
3.16.9
Preamble/Start Frame Delimiter (SFD) Detection
Once receive preamble detected, Repeater State machine device will commence re-transmission preamble permitted output ports, begin searching "two ones" condition preamble. Once Synch character been detected, packet data which follows loaded into internal FIFO, re-transmitted after preamble been completed output ports. device does detect SFD, then will remain preamble generation state until receive carrier dropped collision detected. case IMR+ device, after receive preamble detected, Repeater State machine will commence re-transmission preamble permitted output ports, will ignore (Start Frame Delimiter) which arrives with less than bits preamble. IMR+ device will monitor input stream search until received bits (1.6 preamble. IMR+ device will decode
IMR/IMR+ Overview 3-23
fully, only respond valid pattern (10101011). Once valid byte been detected, packet data which follows loaded into internal FIFO, re-transmitted after preamble been completed output ports. IMR+ device does detect SFD, then will remain preamble generation state until receive carrier dropped collision detected.
3.16.10
Hardware Reset
chip minimum reset pulse requirement This requirement allows receive clock recovery circuitry stabilize. IMR+ device same requirement minimum reset pulse width power however reset applied while power stays active pulse width requirement reset IMR+ chip decreases Note that both IMR+ devices remain reset state clock cycles (0.5 following reset pulse. During reset, receive activity Twisted Pair ports ignored repeater activity started while IMR/IMR+ device internal RESET state. This ensures that packet fragments propagated onto network Management Software Reset (which will occur result Management Station action). reset circuitry IMR+ device ensures that chip internally reset only once, sufficient duration. This avoids multiple resets within device, case where slow rising edge reset signal, crosses input buffer threshold several times ripple input waveform.
3.17
IMR/IMR+ PROPAGATION DELAYS
Since IMR+ device general purpose repeater chip, does directly interface with backplane from specific vendor. Since there numerous existing concentrator backplanes that currently available market place, making part which interfaces variety these trivial problem. IMR+ device utilized design, where previous backwards compatibility required, then dedicated Expansion Port used basis backplane, interconnect individual IMR+ chip groups IMR+ devices, such that modular concentrator architecture accomplished. This concept discussed existing data sheet. order provide maximum flexibility installed base, where backwards compatibility with existing architecture required, necessary describe external behavior IMR+ device, form throughput delays, that designers understand issues ensure that critical repeater delays specified Section 802.3 met. Below listed IMR+ propagation delays parameters. values based combination related empirical data, simulation, bench/tester measurements. general, maximum values have assumed theoretical worst case conditions. Propagation delays cited below, which directly match correspond data sheet parameters IEEE 802.3 requirements, guaranteed production testing. addition, data delays pertaining digital pins considered zero order avoid double counting such delays. paths including digital output buffer input buffer, data delays have been accounted input buffer parameter form range input setup times.
3.17.1
Start Packet Propagation Delays
Note that start packet propagation delays, input signal assumed valid Manchester encoded signal, with first valid amplitude pulse width. input (stimulus) waveform will have direct effect propagation delay. instance, using non-Manchester input into ports, measuring propagation
3-24
IMR/IMR+ Overview
delay output, yield delay value larger than expected, first being valid Manchester.
Parameter Data asserted Data data port Data data Data port asserted Data port data Data port data port Data port data Data DAT/ACK data port Data DAT/ACK data port asserted data (ns) (ns)
3.17.2
Start Collision Propagation Delays
Parameter active sequence active sequence port active sequence active asserted active sequence active sequence port active sequence JAM/ACK asserted sequence JAM/ACK asserted sequence port asserted sequence asserted sequence port (ns) (ns)
Note: Propagation delays cited these tables guaranteed production testing.
IMR/IMR+ Overview
3-25
3.17.3
Collision Propagation Delays
Parameter carrier sense deasserted sequence port CI/DI carrier sense deasserted sequence port CI/DI carrier sense deasserted sequence CI/DI carrier sense deasserted deasserted carrier sense deasserted sequence port carrier sense deasserted sequence other port carrier sense deasserted sequence carrier sense deasserted deasserted JAM/ACK deasserted sequence port JAM/ACK deasserted sequence port deasserted sequence port deasserted sequence port Internal AUI/TP carrier sense deassertion (ns) (ns)
3.17.4
Start-up Steady State Delays
start-up delay, from first edge received waveform first edge transmitted waveform, varies from path includes propagation delays, smart squelch, synchronization transmit clock (X1) repeater state machine processing time with variation introduced propagation delays synchronization time. steady state delay function internal propagation/timing delays well extent which data buffered internal FIFO. depth FIFO usage required depends amount preamble (including SFD) received well magnitude frequency mismatch between extracted receive clock transmit clock. FIFO will nearly empty during transfers involving received preamble bits coupled with fast transmit clock (X1), whereas FIFO will nearly full during transfers involving very short received preamble bits coupled with slow transmit clock (X1). total, steady state delay vary from times.
3.17.5 3.17.6
Receive Active Delay
This parameter identical start-up delay (see above).
Slow Signals
late assertion from external expansion port arbiter does prevent expansion source IMR/IMR+ device from engaging preamble sequence. will drive preamble ports while expansion port remains highimpedance state. Expansion port destination IMR/IMR+ devices will unable repeat preamble bits which normally would have been passed from expansion source during time which tardy. asserted asserted
3-26
IMR/IMR+ Overview
delay which tardy (fails tCASET parameter ns), destination IMR/IMR+ devices will issue preamble sequence which shortened versus source IMR/IMR+ device, that preamble sequence will begin with Manchester zero. late deassertion from external expansion port arbiter will induce destination IMR/IMR+ devices repeat expansion port data even though expansion port being driven with data source IMR/IMR+ device. Again destination deassertion delay will result transmission errant destination IMR/IMR+ devices, resulting undefined "dribbling bit" being added re-transmitted data. deassertion which more than tardy (fails tCASET more than ns), original source IMR/IMR+ device will perceive itself expansion port destination device (ACK asserted, deasserted) will issue minimum 96-bit sequence receiving runt packet. Supplying immediately, followed tardy indication result expansion port contention IMR/IMR+ devices simultaneously request bus.
IMR/IMR+ Overview
3-27
3-28
IMR/IMR+ Overview
SECTION
HIMIB OVERVIEW
Hardware Implemented Management Information Base (HIMIB) device provides complete hardware support high performance network monitoring requirements IEEE 802.3 Repeater Management Standard. HIMIB chip designed used with Integrated Multiport Repeater (IMR+), providing flexible complete solution managed repeater design. also interfaced with Ethernet controller supporting General Purpose Serial Interface (GPSI). IEEE 802.3 repeater management standard defines three management packages, Basic Control, Performance Monitoring, Address Tracking. Both Performance Monitoring Address Tracking require real time statistics collection each repeater port per-frame basis. HIMIB chip, conjunction with IMR+ device, provides complete solution required optional statistics. network activity related statistics will updated autonomously HIMIB device with host processor involvement. HIMIB device connects directly IMR+ Expansion Bus, Management Port Port Activity Monitor (PAM), enabling HIMIB chip directly track count critical network events local remote management queries. Coupled with processor simple IEEE 802.3 MAC, system expanded support complete remote in-band network management capabilities. Additionally HIMIB chip supports Novell, Inc. Management Interface (HMI) extensions IEEE 802.3 Repeater Management requirements. HIMIB chip provides simple 8-bit asynchronous interface, allowing interfacing cost 8-bit microprocessor, provide extremely cost solution managed repeater designs.
ARCHITECTURAL OVERVIEW
HIMIB device autonomously carries statistics accumulation managed repeater applications. These statistics accumulated array registers shown Figure 4-1. register array addressed banks with registers each bank. HIMIB device currently only uses banks, with varying number registers each bank. Each register addressed using Port Number (Bank Number) Register Number (Attribute Number) pointer combination. lower bits both these registers effectively address single attribute register HIMIB chip's register array.
HIMIB Overview
Figure
Control Port
HIMIB Device Register Array
Bank Select Register HIMIB Status Register
Attribute Select Register
IMR+ Management Port Set:
Write issues command IMR+
IMR+ Management Port Get:
Write issues command IMR+ read returns result
Holding Register Data Port
HIMIB Overview
HIMIB/IMR+ CHIP-SET MANAGEMENT CAPABILITIES
Table 4-1A 4-1B listing HIMIB device registers. Table 4-1A, columns register banks, while rows individual registers banks.
Table 4-1Reg
HIMIB Registers
Register Bank Port Status Registers Partition Status Change Partition Status Change Link Status Change Loop Back Error Register Bank Port Control Registers Partition Change Interrupt Enable Partition Change Interrupt Enable Link Status Change Interrupt Enable Loop Back Error Interrupt Enable Register Banks 16-23 10BASE-T Ports Readable Frames Register Bank Port Readable Frames
Register Bank Repeater Registers
Readable Octets
Readable Octets
Frame Check Sequence Errors Alignment Errors
Frame Check Sequence Errors Alignment Errors
Test Error Test Error Interrupt Enable Source Address Change Interrupt Enable Source Address Change Interrupt Enable
Frames Long Short Events
Frames Long Short Events
Source Address Change
Runts
Runts
Source Address Change
Collisions
Collisions
Source Address Match Status Source Address Match Status Source Address Match Bytes)
Late Events
Late Events
Very Long Events
Very Long Events
Data Rate Mismatches Auto Partitions
Data Rate Mismatches Auto Partitions Source Address Changes
Total Octets
Source Address Changes
Transmit Collisions Last Source Address Bytes) Configuration Register Version/Device IMR+ Management Port Register IMR+ Management Port Register Last Source Address Bytes)
HIMIB Overview
Table 4-1B
Register Status Register Port/Register Bank Repeater Registers P[4:0] Note: Read Port Status Need Specify Port Register Number Register Source Address Match Total Octets Transmit Collisions Configuration Register Version/Device IMR+ Management Port Register IMR+ Management Port Register Port Status Registers Partition Status Change Partition Status Change Link Status Change Loop Back Error Reserved Test Error Source Address Change Source Address Change Source Address Match Status Source Address Match Status Port Control Registers Partition Change Interrupt Enable Partition Change Interrupt Enable Link Status Change Interrupt Enable Loop Back Error Interrupt Enable Reserved Test Error Interrupt Enable Source Address Change Interrupt Enable Source Address Change Interrupt Enable Attribute Registers 16-23, Readable Frames Readable Octets Frame Check Sequence Errors Alignment Errors Frames Long Short Events Runts Collisions Late Events Very Long Events Data Rate Mismatches Auto Partitions Source Address Changes Reserved Last Source Address R[4:0]
HIMIB Registers
Bytes Bytes Access Access
Note that register locations listed reserved those which might accessed values combinations which listed table above should accessed software. Read/write access reserved registers cause incorrect operation.
HIMIB Overview
following tables list implementation requirements management objects repeater based IMR+/HIMIB devices. They organized into three tables. first describes management attributes that supported software. second describes management attributes supported directly HIMIB device. third lists management attributes supported IMR+ device. Table list management objects that would typically implemented managed repeaters resident software. These objects generally static, change very infrequently, hence present minimal overhead managed repeater software.
Table Software Management Objects Management Object Name repeaterID repeaterGroupCapacity groupMap repeaterHealthState repeaterHealthText repeaterHealthData resetRepeater executeNonDisruptiveSelfTest repeaterHealth repeaterReset groupMapChange resourceTypeIDName resourceInfo groupID groupPortCapacity portMap portMapChange portID portAdminState portAdminControl
Management Class Repeater Repeater Repeater Repeater Repeater Repeater Repeater Repeater Repeater Repeater Repeater ResourceTypeID ResourceTypeID Group Group Group Group Port Port Port
Object Type Read Only Attribute Read Only Attribute Read Only Attribute Read Only Attribute Read Only Attribute Rea
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