netman 2008-4-13 19:47
ANSI/IEEE Std 802.1G, 1998 Edition
【资料成文时间】：1998
【语言】：English
【页数】： 237
【何人（公司）所著】：IEEE
【文件格式】： PDF
【文件原名】： ANSI/IEEE Std 802.1G, 1998 Edition-Adopted by the ISO/IEC and redesignated asISO/IEC 15802-5:1998(E)
【摘要或目录】：
Contents
CLAUSE PAGE
1. Scope................................................................................................................................................... 1
2. References........................................................................................................................................... 2
3. Definitions........................................................................................................................................... 4
3.1 Definitions related to MAC bridging........................................................................................... 4
3.2 Definitions specific to remote MAC bridging ............................................................................. 4
3.3 Acronyms and abbreviations........................................................................................................ 7
4. Conformance....................................................................................................................................... 7
4.1 Static conformance requirements................................................................................................. 7
4.2 Options........................................................................................................................................ 8
4.3 Protocol implementation conformance statement (PICS)............................................................ 9
5. Support of the MAC service ................................................................................................................ 9
5.1 Provision and support of the MAC service................................................................................ 10
5.2 Preservation of the MAC service............................................................................................... 12
5.3 Quality of service (QOS) maintenance ...................................................................................... 12
5.3.1 Undetected error rate......................................................................................................... 12
5.4 Internal Sublayer Service provided within the remote MAC bridge ......................................... 12
5.5 Support of the Internal Sublayer Service by specific MAC procedures.................................... 14
5.6 Support of the Internal Sublayer Service in remote bridge groups............................................ 14
6. Principles of operation ....................................................................................................................... 14
6.1 Remote bridge operation............................................................................................................ 14
6.1.1 Relay ................................................................................................................................ 14
6.1.2 Filtering Information......................................................................................................... 15
6.1.3 Bridge management .......................................................................................................... 15
6.2 Remote bridge architecture ........................................................................................................ 16
6.2.1 Architectural model of a remote bridge ............................................................................ 16
6.2.2 MAC relay entity .............................................................................................................. 16
6.2.3 Ports ................................................................................................................................. 17
6.2.4 Group communications entity........................................................................................... 17
6.2.5 Higher layer entities.......................................................................................................... 18
6.3 Model of operation of a single remote bridge............................................................................ 18
6.4 Port states, active ports, and the active topology ....................................................................... 24
6.5 Frame reception ......................................................................................................................... 24
6.6 Frame transmission .................................................................................................................... 24
6.7 Frame forwarding...................................................................................................................... 25
6.7.1 Forwarding conditions ...................................................................................................... 25
6.7.2 LLC duplicate address check ............................................................................................ 25
6.7.3 Queued frames .................................................................................................................. 26
6.7.4 Priority mapping ............................................................................................................... 26
6.7.5 Frames addressed to the remote bridge............................................................................. 27
6.8 The learning process .................................................................................................................. 27
6.9 The filtering database................................................................................................................. 28
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Copyright © 1998 IEEE. All rights reserved.
6.9.1 Static entries...................................................................................................................... 28
6.9.2 Dynamic entries ................................................................................................................ 28
6.9.3 Permanent database........................................................................................................... 29
6.10 Bridge protocol entity ................................................................................................................ 29
6.11 Bridge management ................................................................................................................... 29
6.12 Addressing ................................................................................................................................ 30
6.13 Model of remote bridge interconnection.................................................................................... 30
6.13.1 Roles and objectives of the model .................................................................................. 30
6.13.2 Elements of the model .................................................................................................... 31
6.13.3 Static configuration: remote bridge groups, virtual ports, and subgroups...................... 31
6.13.4 The active topology and remote bridge clusters ............................................................. 32
6.13.5 Functions of virtual ports ................................................................................................ 34
6.13.6 Examples of configurations of remote bridge groups and virtual ports.......................... 34
7. The Spanning Tree Algorithm and Protocol...................................................................................... 37
7.1 Introduction............................................................................................................................... 37
7.2 Requirements of the remote MAC bridges ................................................................................ 38
7.3 General description .................................................................................................................... 38
7.3.1 Overview.......................................................................................................................... 38
7.3.2 Computation of the active topology.................................................................................. 40
7.3.3 Protocol support for the Spanning Tree Algorithm .......................................................... 42
7.3.4 Determining the active topology....................................................................................... 43
7.3.5 Reconfiguration................................................................................................................ 45
7.3.6 Notifying topology change ............................................................................................... 46
7.3.7 Changing port state ........................................................................................................... 47
7.3.8 Changes in cluster configuration ...................................................................................... 47
7.4 Port states .................................................................................................................................. 51
7.4.1 Blocking........................................................................................................................... 51
7.4.2 Listening ........................................................................................................................... 52
7.4.3 Learning ............................................................................................................................ 52
7.4.4 Forwarding....................................................................................................................... 53
7.4.5 Disabled ............................................................................................................................ 53
7.5 Protocol parameters ................................................................................................................... 54
7.5.1 Parameters of configuration messages.............................................................................. 54
7.5.2 Parameters of topology change notifications.................................................................... 56
7.5.3 Remote bridge parameters ................................................................................................ 56
7.5.4 Port parameters ................................................................................................................. 58
7.5.5 Remote bridge group parameters ...................................................................................... 60
7.6 Elements of parameter computation for a remote bridge........................................................... 61
7.6.1 Accepting received configuration message information at a port .................................... 61
7.6.2 Updating the bridgeÕs configuration ................................................................................. 62
7.6.3 Recording additional configuration message information for the bridge and group ........ 64
7.6.4 Port state selection ............................................................................................................ 64
7.6.5 Cluster resolution .............................................................................................................. 65
7.6.6 Cluster port state selection ................................................................................................ 66
7.6.7 Cluster confirmation ......................................................................................................... 67
7.6.8 Test for an isolated alternate subgroup port...................................................................... 67
7.6.9 Topology change detection ............................................................................................... 67
7.6.10 Topology change acknowledgment ................................................................................ 68
7.7 Spanning Tree Protocol operation at LAN ports ....................................................................... 68
7.7.1 Protocol operation at a designated port............................................................................. 68
7.7.2 Protocol operation at a root port ....................................................................................... 69
7.7.3 Protocol operation at an alternate port .............................................................................. 70
Copyright © 1998 IEEE. All rights reserved.
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7.8 Management of the bridge protocol entity................................................................................. 70
7.8.1 Initialization ...................................................................................................................... 70
7.8.2 Enable Port........................................................................................................................ 71
7.8.3 Disable Port....................................................................................................................... 71
7.8.4 Set Bridge Priority ............................................................................................................ 71
7.8.5 Set Port Priority................................................................................................................. 71
7.8.6 Set Path Cost ..................................................................................................................... 72
7.9 Encoding and validation of BPDUs on LANs ........................................................................... 72
7.10 Performance ............................................................................................................................... 72
7.10.1 Requirements .................................................................................................................. 72
7.10.2 Parameter values ............................................................................................................. 73
7.10.3 Bridge diameter and effective bridge count.................................................................... 73
7.10.4 Remote bridging transit and propagation delays ............................................................ 73
7.10.5 Reclustering delay parameters, and relationships with forward delay ........................... 74
7.10.6 Path costs for virtual ports .............................................................................................. 75
8. Relaying by remote bridges ............................................................................................................... 75
8.1 Relaying connectivity requirement ............................................................................................ 75
8.2 Relaying QOS requirements ...................................................................................................... 76
8.2.1 Misordering and duplication ............................................................................................. 76
8.2.2 Loss .................................................................................................................................. 76
8.2.3 Undetected error rate......................................................................................................... 77
8.2.4 Transit delay...................................................................................................................... 77
8.2.5 Maximum MSDU size ...................................................................................................... 77
8.2.6 Priority .............................................................................................................................. 77
8.3 Cluster integrity requirements.................................................................................................... 77
8.3.1 Virtual LANs .................................................................................................................... 77
8.3.2 Frames transmitted on subgroup ports.............................................................................. 78
8.3.3 Frames received on subgroup ports .................................................................................. 78
9. Bridge management ........................................................................................................................... 79
9.1 Management functions............................................................................................................... 79
9.2 Managed objects ........................................................................................................................ 79
9.3 Data types.................................................................................................................................. 79
9.4 Bridge management entity ......................................................................................................... 79
9.4.1 Bridge Configuration ........................................................................................................ 79
9.4.2 Port Configuration ............................................................................................................ 81
9.4.3 Group Configuration......................................................................................................... 82
9.5 MAC entities............................................................................................................................. 83
9.6 Forwarding Process.................................................................................................................... 83
9.6.1 The Port Counters ............................................................................................................. 84
9.6.2 Transmission Priority........................................................................................................ 84
9.7 The filtering database................................................................................................................. 85
9.7.1 Filtering Database managed object................................................................................... 85
9.7.2 Static Entry........................................................................................................................ 85
9.7.3 Dynamic Entry .................................................................................................................. 86
9.7.4 Permanent Database.......................................................................................................... 86
9.7.5 General filtering database operations................................................................................ 86
9.8 The bridge protocol entity.......................................................................................................... 87
9.8.1 Bridge Protocol Entity managed object ........................................................................... 88
9.8.2 Bridge Port ........................................................................................................................ 89
9.8.3 Remote Bridge Group ....................................................................................................... 91
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Copyright © 1998 IEEE. All rights reserved.
10. Management protocol ........................................................................................................................ 92
10.1 Mapping of operations onto LMMS services ........................................................................... 92
10.2 Managed object containment structure ...................................................................................... 94
10.3 Additions to MAC Bridge DLE managed object class definition ............................................. 95
10.3.1 Remote MAC Bridge conditional package definition .................................................... 95
10.3.2 Bridge Number of Virtual LANs attribute definition ..................................................... 96
10.3.3 Bridge Number of Non-Virtual-LAN Groups attribute definition ................................. 96
10.3.4 Bridge Number of Subgroup Ports attribute definition................................................... 96
10.3.5 Bridge Virtual Ports attribute definition ......................................................................... 97
10.4 Additions to Port managed object class definition .................................................................... 97
10.4.1 Subgroup Port Parameters conditional package definition............................................. 97
10.4.2 Peer New Cluster Identifier attribute definition.............................................................. 97
10.4.3 Peer Old Cluster Identifier attribute definition ............................................................... 98
10.5 Group managed object class and attributes................................................................................ 98
10.5.1 Group managed object class definition........................................................................... 98
10.5.2 Group Number attribute definition ................................................................................. 99
10.5.3 Group Name attribute definition..................................................................................... 99
10.5.4 Group Virtual Ports attribute definition.......................................................................... 99
10.5.5 Reclustering State attribute definition ............................................................................ 99
10.5.6 Current Cluster Identifier attribute definition ............................................................... 100
10.5.7 New Cluster Identifier attribute definition.................................................................... 100
10.5.8 Old Cluster Identifier attribute definition ..................................................................... 100
10.5.9 Reclustering Delay attribute definition......................................................................... 100
10.5.10 Primary Reclustering Delay attribute definition ......................................................... 101
10.5.11 Read Group attribute group definition........................................................................ 101
10.5.12 Read Group Parameters attribute group definition ..................................................... 101
10.6 ASN.1 definitions .................................................................................................................... 102
11. Performance .................................................................................................................................... 102
12. The Extended Spanning Tree Protocol ............................................................................................ 103
12.1 Introduction............................................................................................................................. 103
12.2 Bridge-protocol support in remote bridge groups.................................................................... 103
12.2.1 RB-Protocol Subnetwork Service ................................................................................. 103
12.2.2 Group connectivity requirement ................................................................................... 105
12.2.3 Mapping of BPDU transfer to the RB-Protocol Subnetwork Service .......................... 106
12.3 Protocol parameters and timers................................................................................................ 106
12.3.1 Parameters of Configuration BPDUs............................................................................ 106
12.3.2 Parameters of Topology Change Notification BPDUs ................................................. 106
12.3.3 Remote bridge parameters ............................................................................................ 107
12.3.4 Remote bridge timers.................................................................................................... 107
12.3.5 Port parameters ............................................................................................................. 107
12.3.6 Port timers..................................................................................................................... 108
12.3.7 Remote bridge group parameters .................................................................................. 108
12.3.8 Reclustering Delay Timer ............................................................................................. 108
12.4 Encoding of BPDUs on LANs................................................................................................. 108
12.5 Encoding of Extended Spanning Tree Protocol BPDUs in remote bridge groups .................. 109
12.5.1 BPDU structure............................................................................................................. 109
12.5.2 Encoding of parameter types ........................................................................................ 110
12.5.3 Formats and parameters for BPDUs of the Extended Spanning Tree Protocol............ 111
12.5.4 Validation of received BPDUs...................................................................................... 114
12.6 Elements of procedure ............................................................................................................. 114
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12.6.1 Transmit Configuration BPDU ..................................................................................... 115
12.6.2 Record configuration information.................................................................................. l16
12.6.3 Record configuration timeout values ............................................................................ 116
12.6.4 Configuration BPDU generation.................................................................................... l16
12.6.5 Reply to Configuration BPDU...................................................................................... 116
12.6.6 Transmit Topology Change Notification BPDU .......................................................... 117
12.6.7 Configuration update .................................................................................................... 117
12.6.8 Root selection................................................................................................................ 117
12.6.9 Designated port selection.............................................................................................. 117
12.6.10 Become designated port.............................................................................................. 118
12.6.11 Port state selection ...................................................................................................... 118
12.6.12 Make forwarding......................................................................................................... 118
12.6.13 Make blocking ............................................................................................................ 118
12.6.14 Topology change detection ......................................................................................... 118
12.6.15 Topology change acknowledged................................................................................. 119
12.6.16 Acknowledge topology change.................................................................................... l l9
12.6.17 Cluster selection........................................................................................................... l l9
12.6.18 Cluster resolution ........................................................................................................ 120
12.6.19 Cluster port state selection .......................................................................................... 120
12.6.20 Cluster confirmation ................................................................................................... 121
12.7 Operation of the protocol .......................................................................................................... l21
12.7.1 Received Configuration BPDU..................................................................................... 121
12.7.2 Received Topology Change Notification BPDU.......................................................... 122
12.7.3 Hello Timer expiry........................................................................................................ 122
12.7.4 Message Age Timer expiry........................................................................................... 122
12.7.5 Forward Delay Timer expiry ......................................................................................... l22
12.7.6 Topology Change Notification Timer expiry ................................................................ l22
12.7.7 Topology Change Timer expiry.................................................................................... 122
12.7.8 Hold Timer expiry.......................................................................................................... l22
12.7.9 Reclustering Delay Timer expiry................................................................................... l23
12.8 Management of the bridge protocol entity............................................................................... 123
12.8.1 Initialization .................................................................................................................. 123
12.8.2 Enable port .................................................................................................................... 124
12.8.3 Disable port................................................................................................................... 124
12.8.4 Set bridge priority ......................................................................................................... 124
12.8.5 Set port priority ............................................................................................................. 124
12.8.6 Set path cost .................................................................................................................. 124
13. The Extended Spanning Tree Protocol: Procedural model............................................................... l25
Annex A (normative) PICS proforma....................................................................................................... 159
A.1 Introduction..................................................................................................................... 159
A.2 Abbreviations and special symbols.................................................................................. 159
A.2.1 Status symbols........................................................................................................ 159
A.2.2 General abbreviations ............................................................................................ 160
A.3 Instructions for completing the PICS proforma............................................................... 160
A.3.1 General structure of the PICS proforma ................................................................ 160
A.3.2 Additional Information .......................................................................................... 160
A.3.3 Exception Information ........................................................................................... 161
A.3.4 Conditional status................................................................................................... 161
A.4 PICS proformaÑISO/IEC 15802-5: 1998: Identification ............................................... 162
A.4.1 Implementation identification ................................................................................ 162
A.4.2 Protocol summary, ISO/IEC 15802-5: 1998.......................................................... 162
A.5 Major capabilities and options ......................................................................................... 163
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Copyright © 1998 IEEE. All rights reserved.
A.6 Relay and filtering of frames ........................................................................................... 165
A.7 Maintenance of filtering information................................................................................ l66
A.8 Addressing ....................................................................................................................... 167
A.9 Spanning Tree Algorithm ................................................................................................ 168
A.9.1 Bridge, group, and port parameters........................................................................ 168
A.9.2 Spanning Tree Protocol at LAN ports.................................................................... 169
A.9.3 Spanning tree timers............................................................................................... 169
A.9.4 Management of spanning tree topology and timers ............................................... 170
A.9.5 BPDUs transmitted and received at LAN ports ..................................................... 170
A.10 Extended Spanning Tree Protocol ................................................................................... 171
A.11 Bridge management ......................................................................................................... 173
A.12 Performance and parameter values .................................................................................. 174
Annex B (normative) Allocation of object identifier values .................................................................... 175
B.1 Introduction..................................................................................................................... 175
B.2 Allocation tables .............................................................................................................. 175
Annex C (informative) Background information and tutorial ................................................................. 179
C.1 Introduction..................................................................................................................... 179
C.5 Support of the MAC service ............................................................................................ 179
C.5.3 Quality of service maintenance .............................................................................. 179
C.5.3.1 Service availability....................................................................................... l79
C.5.3.2 Frame loss ................................................................................................... 180
C.5.3.3 Frame misordering ...................................................................................... 180
C.5.3.4 Frame duplication........................................................................................ 180
C.5.3.5 Transit delay................................................................................................. l81
C.5.3.6 Frame lifetime ............................................................................................. 181
C.5.3.7 Undetected frame error rate......................................................................... 181
C.5.3.8 Maximum MSDU size ................................................................................ 182
C.5.3.9 Priority......................................................................................................... 182
C.5.3.10 Throughput ................................................................................................ 182
C.6 Principles of operation ..................................................................................................... 182
C.6.13 Model of remote bridge interconnection.............................................................. 182
C.6.13.1 Virtual ports and underlying communications configurations.................. 182
C.7 The Spanning Tree Algorithm and Protocol.................................................................... 186
C.7.1 Requirements on the algorithm .............................................................................. 186
C.7.3 Spanning Tree Algorithm and cluster configuration.............................................. 186
C.7.3.1 Cluster reconfiguration................................................................................ 187
C.7.3.2 Introduction to the examples, and configuration 1...................................... 188
C.7.3.3 Example configuration 2: Indirect spanning tree path through a group...... 191
C.7.3.4 Example configuration 3: Isolated bridge in G1 ......................................... 192
C.7.3.5 Example configuration 4: Different root, same connectivity...................... 194
C.7.3.6 Example configuration 5: Partitioned group with two active clusters ........ 196
C.7.3.7 Dynamic reconfigurationÑEC1 to EC4, cluster rotation ........................... 197
C.7.3.8 Dynamic reconfigurationÑEC1 to/from EC3, leaving and joining
clusters ..................................................................................................................... 202
C.7.3.9 Dynamic reconfigurationÑEC 1 to EC5, partitioning a cluster ................. 204
C.7.3.10 Dynamic reconfigurationÑEC5 to EC6, transfer between clusters ......... 205
C.7.3.11 Dynamic reconfigurationÑEC6 to EC7, merging clusters....................... 206
C.7.3.12 Dynamic reconfigurationÑEC7 to EC8 ................................................... 209
C.7.10 Performance and reclustering periods .................................................................. 211
C.8 Relaying by remote bridges ............................................................................................. 212
C.8.1 Relaying Requirements and Mechanisms .............................................................. 212
C.8.2 Relaying in steady-state configurations ................................................................. 212
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C.8.2.1 Correctness .................................................................................................. 213
C.8.2.2 Service availability...................................................................................... 213
C.8.2.3 Bandwidth efficiency .................................................................................. 213
C.8.2.4 Correctness in partitioned groups................................................................ 213
C.8.2.5 Bandwidth efficiency in partitioned subgroups .......................................... 214
C.8.2.6 Bandwidth efficiency within subgroups...................................................... 214
C.8.3 Relaying during configuration changes.................................................................. 214
C.8.3.1 Correctness and topology changes .............................................................. 215
C.8.3.2 Service availability and topology changes .................................................. 215
C.8.3.3 Changes in cluster membership................................................................... 215
C.8.3.4 Changes in cluster identifier without change in cluster membership.......... 216
C.12 The Extended Spanning Tree Protocol.............................................................................. 216
C.12.2 Bridge-protocol support in remote bridge groups ................................................ 216
Annex D (informative) Relationship with ISO/IEC 10038: 1993 ............................................................ 217
D.1 Introduction..................................................................................................................... 217
D.2 References....................................................................................................................... 218
D.3 Definitions....................................................................................................................... 218
D.4 Conformance.................................................................................................................... 218
D.5 Support of the MAC service ............................................................................................ 218
D.6 Principles of operation ..................................................................................................... 218
D.7 The Spanning Tree Algorithm and Protocol.................................................................... 219
D.8 Relaying by remote bridges ............................................................................................. 219
D.9 Bridge management ......................................................................................................... 219
D.10 Management protocol ...................................................................................................... 220
D. 11 Performance ..................................................................................................................... 220
D.12 The Extended Spanning Tree Protocol ............................................................................ 220
D.13 The Extended Spanning Tree Protocol: Procedural model.............................................. 221