File: rfc1493.txt

package info (click to toggle)
doc-rfc 20181229-2
  • links: PTS, VCS
  • area: non-free
  • in suites: buster
  • size: 570,944 kB
  • sloc: xml: 285,646; sh: 107; python: 90; perl: 42; makefile: 14
file content (1907 lines) | stat: -rw-r--r-- 74,493 bytes parent folder | download | duplicates (7)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907






Network Working Group                                          E. Decker
Request for Comments: 1493                           cisco Systems, Inc.
Obsoletes: 1286                                              P. Langille
                                           Digital Equipment Corporation
                                                          A. Rijsinghani
                                           Digital Equipment Corporation
                                                           K. McCloghrie
                                                Hughes LAN Systems, Inc.
                                                               July 1993


                     Definitions of Managed Objects
                              for Bridges

Status of this Memo


   This RFC specifies an IAB standards track protocol for the Internet
   community, and requests discussion and suggestions for improvements.
   Please refer to the current edition of the "IAB Official Protocol
   Standards" for the standardization state and status of this protocol.
   Distribution of this memo is unlimited.

Abstract

   This memo defines a portion of the Management Information Base (MIB)
   for use with network management protocols in TCP/IP based internets.
   In particular it defines objects for managing MAC bridges based on
   the IEEE 802.1D-1990 standard between Local Area Network (LAN)
   segments.  Provisions are made for support of transparent bridging.
   Provisions are also made so that these objects apply to bridges
   connected by subnetworks other than LAN segments.

Table of Contents

   1. The Network Management Framework ......................    2
   2. Objects ...............................................    2
   2.1 Format of Definitions ................................    3
   3. Overview ..............................................    3
   3.1 Structure of MIB .....................................    3
   3.1.1 The dot1dBase Group ................................    6
   3.1.2 The dot1dStp Group .................................    6
   3.1.3 The dot1dSr Group ..................................    6
   3.1.4 The dot1dTp Group ..................................    6
   3.1.5 The dot1dStatic Group ..............................    6
   3.2 Relationship to Other MIBs ...........................    6
   3.2.1 Relationship to the 'system' group .................    6
   3.2.2 Relationship to the 'interfaces' group .............    7



Decker, Langille, Rijsinghani & McCloghrie                      [Page 1]

RFC 1493                       Bridge MIB                      July 1993


   3.3 Textual Conventions ..................................    8
   4. Changes from RFC 1286 .................................    8
   5. Definitions ...........................................    9
   5.1 Groups in the Bridge MIB .............................   11
   5.2 The dot1dBase Group Definitions ......................   11
   5.3 The dot1dStp Group Definitions .......................   14
   5.4 The dot1dTp Group Definitions ........................   22
   5.5 The dot1dStatic Group Definitions ....................   28
   5.6 Traps for use by Bridges .............................   31
   6. Acknowledgments .......................................   31
   7. References ............................................   33
   8. Security Considerations ...............................   33
   9. Authors' Addresses ....................................   34

1.  The Network Management Framework

   The Internet-standard Network Management Framework consists of three
   components.  They are:

      STD16/RFC 1155 which defines the SMI, the mechanisms used for
      describing and naming objects for the purpose of management.
      STD16/RFC 1212 defines a more concise description mechanism, which
      is wholly consistent with the SMI.

      RFC 1156 which defines MIB-I, the core set of managed objects for
      the Internet suite of protocols.  STD17/RFC 1213, defines MIB-II,
      an evolution of MIB-I based on implementation experience and new
      operational requirements.

      STD15/RFC 1157 which defines the SNMP, the protocol used for
      network access to managed objects.

   The Framework permits new objects to be defined for the purpose of
   experimentation and evaluation.

2.  Objects

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the subset of Abstract Syntax Notation One (ASN.1) [7]
   defined in the SMI.  In particular, each object is named by an OBJECT
   IDENTIFIER, an administratively assigned name, which specifies an
   object type.  The object type together with an object instance serves
   to uniquely identify a specific instantiation of the object.  For
   human convenience, we often use a textual string, termed the
   descriptor, to also refer to the object type.





Decker, Langille, Rijsinghani & McCloghrie                      [Page 2]

RFC 1493                       Bridge MIB                      July 1993


2.1.  Format of Definitions

   Section 5 contains the specification of all object types contained in
   this MIB module.  The object types are defined using the conventions
   defined in the SMI, as amended by the extensions specified in [9,10].

3.  Overview

   A common device present in many networks is the Bridge.  This device
   is used to connect Local Area Network segments below the network
   layer.

   There are two major modes defined for this bridging; transparent and
   source route.  The transparent method of bridging is defined in the
   draft IEEE 802.1d specification [11].  This memo defines those
   objects needed for the management of a bridging entity operating in
   the transparent mode, as well as some objects applicable to all types
   of bridges.

   To be consistent with IAB directives and good engineering practice,
   an explicit attempt was made to keep this MIB as simple as possible.
   This was accomplished by applying the following criteria to objects
   proposed for inclusion:

          (1)  Start with a small set of essential objects and add only
               as further objects are needed.

          (2)  Require objects be essential for either fault or
               configuration management.

          (3)  Consider evidence of current use and/or utility.

          (4)  Limit the total of objects.

          (5)  Exclude objects which are simply derivable from others in
               this or other MIBs.

          (6)  Avoid causing critical sections to be heavily
               instrumented.  The guideline that was followed is one
               counter per critical section per layer.

3.1.  Structure of MIB

   Objects in this MIB are arranged into groups.  Each group is
   organized as a set of related objects.  The overall structure and
   assignment of objects to their groups is shown below.  Where
   appropriate the corresponding IEEE 802.1d [11] management object name
   is also included.



Decker, Langille, Rijsinghani & McCloghrie                      [Page 3]

RFC 1493                       Bridge MIB                      July 1993


          Bridge MIB Name                  IEEE 802.1d Name

          dot1dBridge
            dot1dBase
              BridgeAddress                Bridge.BridgeAddress
              NumPorts                     Bridge.NumberOfPorts
              Type
              PortTable
                Port                       BridgePort.PortNumber
                IfIndex
                Circuit
                DelayExceededDiscards        .DiscardTransitDelay
                MtuExceededDiscards          .DiscardOnError
            dot1dStp
              ProtocolSpecification
              Priority                     SpanningTreeProtocol
                                             .BridgePriority
              TimeSinceTopologyChange        .TimeSinceTopologyChange
              TopChanges                     .TopologyChangeCount
              DesignatedRoot                 .DesignatedRoot
              RootCost                       .RootCost
              RootPort                       .RootPort
              MaxAge                         .MaxAge
              HelloTime                      .HelloTime
              HoldTime                       .HoldTime
              ForwardDelay                   .ForwardDelay
              BridgeMaxAge                   .BridgeMaxAge
              BridgeHelloTime                .BridgeHelloTime
              BridgeForwardDelay             .BridgeForwardDelay
              PortTable
                Port                        SpanningTreeProtocolPort
                                              .PortNumber
                Priority                      .PortPriority
                State                         .SpanningTreeState
                Enable
                PathCost                      .PortPathCost
                DesignatedRoot                .DesignatedRoot
                DesignatedCost                .DesignatedCost
                DesignatedBridge              .DesignatedBridge
                DesignatedPort                .DesignatedPort
                ForwardTransitions
            dot1dTp
              LearnedEntryDiscards          BridgeFilter.DatabaseSize
                                              .NumDynamic,NumStatic
              AgingTime                     BridgeFilter.AgingTime
              FdbTable
                Address
                Port



Decker, Langille, Rijsinghani & McCloghrie                      [Page 4]

RFC 1493                       Bridge MIB                      July 1993


                Status
              PortTable
                Port
                MaxInfo
                InFrames                    BridgePort.FramesReceived
                OutFrames                     .ForwardOutbound
                InDiscards                    .DiscardInbound
            dot1dStatic
              StaticTable
                Address
                ReceivePort
                AllowedToGoTo
                Status

   The following IEEE 802.1d management objects have not been included
   in the Bridge MIB for the indicated reasons.

          IEEE 802.1d Object              Disposition

          Bridge.BridgeName               Same as sysDescr (MIB II)
          Bridge.BridgeUpTime             Same as sysUpTime (MIB II)
          Bridge.PortAddresses            Same as ifPhysAddress (MIB II)
          BridgePort.PortName             Same as ifDescr (MIB II)
          BridgePort.PortType             Same as ifType (MIB II)
          BridgePort.RoutingType          Derivable from the implemented
                                          groups

          SpanningTreeProtocol
              .BridgeIdentifier           Combination of dot1dStpPriority
                                          and dot1dBaseBridgeAddress
              .TopologyChange             Since this is transitory, it
                                          is not considered useful.
          SpanningTreeProtocolPort
              .Uptime                     Same as ifLastChange (MIB II)
              .PortIdentifier             Combination of dot1dStpPort
                                          and dot1dStpPortPriority
              .TopologyChangeAcknowledged Since this is transitory, it
                                          is not considered useful.
              .DiscardLackOfBuffers       Redundant

          Transmission Priority           These objects are not required
                                          as per the Pics Proforma and
                                          not considered useful.
              .TransmissionPriorityName
              .OutboundUserPriority
              .OutboundAccessPriority





Decker, Langille, Rijsinghani & McCloghrie                      [Page 5]

RFC 1493                       Bridge MIB                      July 1993


3.1.1.  The dot1dBase Group

   This mandatory group contains the objects which are applicable to all
   types of bridges.

3.1.2.  The dot1dStp Group

   This group contains the objects that denote the bridge's state with
   respect to the Spanning Tree Protocol.  If a node does not
   implemented the Spanning Tree Protocol, this group will not be
   implemented.

3.1.3.  The dot1dSr Group

   This group contains the objects that describe the entity's state with
   respect to source route bridging.  If source routing is not supported
   this group will not be implemented.  This group is applicable to
   source route only, and SRT bridges.  This group will be described in
   a separate document applicable only to source route bridging.

3.1.4.  The dot1dTp Group

   This group contains objects that describe the entity's state with
   respect to transparent bridging.  If transparent bridging is not
   supported this group will not be implemented.  This group is
   applicable to transparent only and SRT bridges.

3.1.5.  The dot1dStatic Group

   This group contains objects that describe the entity's state with
   respect to destination-address filtering.  If destination-address
   filtering is not supported this group will not be implemented.  This
   group is applicable to any type of bridge which performs
   destination-address filtering.

3.2.  Relationship to Other MIBs

   As described above, some IEEE 802.1d management objects have not been
   included in this MIB because they overlap with objects in other MIBs
   applicable to a bridge implementing this MIB.  In particular, it is
   assumed that a bridge implementing this MIB will also implement (at
   least) the 'system' group and the 'interfaces' group defined in MIB-
   II [6].

3.2.1.  Relationship to the 'system' group

   In MIB-II, the 'system' group is defined as being mandatory for all
   systems such that each managed entity contains one instance of each



Decker, Langille, Rijsinghani & McCloghrie                      [Page 6]

RFC 1493                       Bridge MIB                      July 1993


   object in the 'system' group.  Thus, those objects apply to the
   entity as a whole irrespective of whether the entity's sole
   functionality is bridging, or whether bridging is only a subset of
   the entity's functionality.

3.2.2.  Relationship to the 'interfaces' group

   In MIB-II, the 'interfaces' group is defined as being mandatory for
   all systems and contains information on an entity's interfaces, where
   each interface is thought of as being attached to a `subnetwork'.
   (Note that this term is not to be confused with `subnet' which refers
   to an addressing partitioning scheme used in the Internet suite of
   protocols.) The term 'segment' is used in this memo to refer to such
   a subnetwork, whether it be an Ethernet segment, a 'ring', a WAN
   link, or even an X.25 virtual circuit.

   Implicit in this Bridge MIB is the notion of ports on a bridge.  Each
   of these ports is associated with one interface of the 'interfaces'
   group, and in most situations, each port is associated with a
   different interface. However, there are situations in which multiple
   ports are associated with the same interface.  An example of such a
   situation would be several ports each corresponding one-to-one with
   several X.25 virtual circuits but all on the same interface.

   Each port is uniquely identified by a port number.  A port number has
   no mandatory relationship to an interface number, but in the simple
   case a port number will have the same value as the corresponding
   interface's interface number.  Port numbers are in the range
   (1..dot1dBaseNumPorts).

   Some entities perform other functionality as well as bridging through
   the sending and receiving of data on their interfaces.  In such
   situations, only a subset of the data sent/received on an interface
   is within the domain of the entity's bridging functionality.  This
   subset is considered to be delineated according to a set of
   protocols, with some protocols being bridged, and other protocols not
   being bridged. For example, in an entity which exclusively performed
   bridging, all protocols would be considered as being bridged, whereas
   in an entity which performed IP routing on IP datagrams and only
   bridged other protocols, only the non-IP data would be considered as
   being bridged.

   Thus, this Bridge MIB (and in particular, its counters) are
   applicable only to that subset of the data on an entity's interfaces
   which is sent/received for a protocol being bridged.  All such data
   is sent/received via the ports of the bridge.





Decker, Langille, Rijsinghani & McCloghrie                      [Page 7]

RFC 1493                       Bridge MIB                      July 1993


3.3.  Textual Conventions

   The datatypes, MacAddress, BridgeId and Timeout, are used as textual
   conventions in this document.  These textual conventions have NO
   effect on either the syntax nor the semantics of any managed object.
   Objects defined using these conventions are always encoded by means
   of the rules that define their primitive type.  Hence, no changes to
   the SMI or the SNMP are necessary to accommodate these textual
   conventions which are adopted merely for the convenience of readers.

4.  Changes from RFC 1286

          (1)  Updated all text to remove references to source route
               bridging where not applicable.  SR MIB will be a separate
               document.

          (2)  Removed dot1dSrPortTable.  Retained OID definition of
               dot1dSr.

          (3)  Updated all references of "draft P802.1d/D9" to "IEEE
               802.1D-1990".

          (4)  Updated bibliography.

          (5)  Added clarification to description of dot1dPortPathCost.

          (6)  Put recommended default in description of
               dot1dStaticAllowedToGoTo.

          (7)  Put recommended default in description of
               dot1dStaticStatus.

          (8)  Put recommended default in description of
               dot1dTpAgingTime.  Specified range of (10..1000000).

          (9)  Updated all port number syntaxes, when used as index, to
               use the range (1..65535).

          (10) Updated definition of dot1dTpPortInFrames and
               dot1dTpPortOutFrames.

          (11) Added text to the traps indicating that they are
               optional.

          (12) Clarified definition of dot1dStpForwardDelay.






Decker, Langille, Rijsinghani & McCloghrie                      [Page 8]

RFC 1493                       Bridge MIB                      July 1993


5.  Definitions

          BRIDGE-MIB DEFINITIONS ::= BEGIN

          IMPORTS
                     Counter, TimeTicks
                             FROM RFC1155-SMI
                     mib-2
                             FROM RFC1213-MIB
                     OBJECT-TYPE
                             FROM RFC-1212
                     TRAP-TYPE
                             FROM RFC-1215;

          -- All representations of MAC addresses in this MIB Module
          -- use, as a textual convention (i.e. this convention does
          -- not affect their encoding), the data type:

          MacAddress ::= OCTET STRING (SIZE (6))    -- a 6 octet address
                                                    -- in the
                                                    -- "canonical"
                                                    -- order
          -- defined by IEEE 802.1a, i.e., as if it were transmitted
          -- least significant bit first, even though 802.5 (in
          -- contrast to other n802.x protocols) requires MAC
          -- addresses to be transmitted most significant bit first.
          --
          -- 16-bit addresses, if needed, are represented by setting
          -- their upper 4 octets to all 0's, i.e., AAFF would be
          -- represented as 00000000AAFF.


          -- Similarly, all representations of Bridge-Id in this MIB
          -- Module use, as a textual convention (i.e. this
          -- convention does not affect their encoding), the data
          -- type:

          BridgeId ::= OCTET STRING (SIZE (8))   -- the
                                                 -- Bridge-Identifier
                                                 -- as used in the
                                                 -- Spanning Tree
          -- Protocol to uniquely identify a bridge.  Its first two
          -- octets (in network byte order) contain a priority
          -- value and its last 6 octets contain the MAC address
          -- used to refer to a bridge in a unique fashion
          -- (typically, the numerically smallest MAC address
          -- of all ports on the bridge).




Decker, Langille, Rijsinghani & McCloghrie                      [Page 9]

RFC 1493                       Bridge MIB                      July 1993


          -- Several objects in this MIB module represent values of
          -- timers used by the Spanning Tree Protocol.  In this
          -- MIB, these timers have values in units of hundreths of
          -- a second (i.e. 1/100 secs).
          -- These timers, when stored in a Spanning Tree Protocol's
          -- BPDU, are in units of 1/256 seconds.  Note, however,
          -- that 802.1D-1990 specifies a settable granularity of
          -- no more than 1 second for these timers.  To avoid
          -- ambiguity, a data type is defined here as a textual
          -- convention and all representation of these timers
          -- in this MIB module are defined using this data type.  An
          -- algorithm is also defined for converting between the
          -- different units, to ensure a timer's value is not
          -- distorted by multiple conversions.
          -- The data type is:

          Timeout ::= INTEGER -- a STP timer in units of 1/100 seconds

          -- To convert a Timeout value into a value in units of
          -- 1/256 seconds, the following algorithm should be used:
          --
          --      b  = floor( (n * 256) / 100)
          --
          -- where:
          --      floor   =  quotient [ignore remainder]
          --      n is the value in 1/100 second units
          --      b is the value in 1/256 second units
          --
          -- To convert the value from 1/256 second units back to
          -- 1/100 seconds, the following algorithm should be used:
          --
          --      n = ceiling( (b * 100) / 256)
          --
          -- where:
          --      ceiling =  quotient [if remainder is 0], or
          --                 quotient + 1 [if remainder is non-zero]
          --      n is the value in 1/100 second units
          --      b is the value in 1/256 second units
          --
          -- Note: it is important that the arithmetic operations are
          -- done in the order specified (i.e., multiply first, divide
          -- second).


             dot1dBridge   OBJECT IDENTIFIER ::= { mib-2 17 }






Decker, Langille, Rijsinghani & McCloghrie                     [Page 10]

RFC 1493                       Bridge MIB                      July 1993


          -- groups in the Bridge MIB

          dot1dBase     OBJECT IDENTIFIER ::= { dot1dBridge 1 }

          dot1dStp      OBJECT IDENTIFIER ::= { dot1dBridge 2 }

          dot1dSr       OBJECT IDENTIFIER ::= { dot1dBridge 3 }
          -- separately documented

          dot1dTp       OBJECT IDENTIFIER ::= { dot1dBridge 4 }

          dot1dStatic   OBJECT IDENTIFIER ::= { dot1dBridge 5 }


          -- the dot1dBase group

          -- Implementation of the dot1dBase group is mandatory for all
          -- bridges.

          dot1dBaseBridgeAddress OBJECT-TYPE
              SYNTAX  MacAddress
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The MAC address used by this bridge when it must
                      be referred to in a unique fashion.   It is
                      recommended that this be the numerically smallest
                      MAC address of all ports that belong to this
                      bridge.  However it is only required to be unique.
                      When concatenated with dot1dStpPriority a unique
                      BridgeIdentifier is formed which is used in the
                      Spanning Tree Protocol."
              REFERENCE
                      "IEEE 802.1D-1990: Sections 6.4.1.1.3 and 3.12.5"
              ::= { dot1dBase 1 }

          dot1dBaseNumPorts OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of ports controlled by this bridging
                      entity."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.4.1.1.3"
              ::= { dot1dBase 2 }

          dot1dBaseType OBJECT-TYPE



Decker, Langille, Rijsinghani & McCloghrie                     [Page 11]

RFC 1493                       Bridge MIB                      July 1993


              SYNTAX  INTEGER {
                          unknown(1),
                          transparent-only(2),
                          sourceroute-only(3),
                          srt(4)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "Indicates what type of bridging this bridge can
                      perform.  If a bridge is actually performing a
                      certain type of bridging this will be indicated by
                      entries in the port table for the given type."
              ::= { dot1dBase 3 }

          -- The Generic Bridge Port Table

          dot1dBasePortTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dBasePortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table that contains generic information about
                      every port that is associated with this bridge.
                      Transparent, source-route, and srt ports are
                      included."
              ::= { dot1dBase 4 }

          dot1dBasePortEntry OBJECT-TYPE
              SYNTAX  Dot1dBasePortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A list of information for each port of the
                      bridge."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.4.2, 6.6.1"
              INDEX  { dot1dBasePort }
              ::= { dot1dBasePortTable 1 }


          Dot1dBasePortEntry ::=
              SEQUENCE {
                  dot1dBasePort
                      INTEGER,
                  dot1dBasePortIfIndex
                      INTEGER,
                  dot1dBasePortCircuit



Decker, Langille, Rijsinghani & McCloghrie                     [Page 12]

RFC 1493                       Bridge MIB                      July 1993


                      OBJECT IDENTIFIER,
                  dot1dBasePortDelayExceededDiscards
                      Counter,
                  dot1dBasePortMtuExceededDiscards
                      Counter
              }

          dot1dBasePort OBJECT-TYPE
              SYNTAX  INTEGER (1..65535)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port number of the port for which this entry
                      contains bridge management information."
              ::= { dot1dBasePortEntry 1 }

          dot1dBasePortIfIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The value of the instance of the ifIndex object,
                      defined in MIB-II, for the interface corresponding
                      to this port."
              ::= { dot1dBasePortEntry 2 }

          dot1dBasePortCircuit OBJECT-TYPE
              SYNTAX  OBJECT IDENTIFIER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "For a port which (potentially) has the same value
                      of dot1dBasePortIfIndex as another port on the
                      same bridge, this object contains the name of an
                      object instance unique to this port.  For example,
                      in the case where multiple ports correspond one-
                      to-one with multiple X.25 virtual circuits, this
                      value might identify an (e.g., the first) object
                      instance associated with the X.25 virtual circuit
                      corresponding to this port.

                      For a port which has a unique value of
                      dot1dBasePortIfIndex, this object can have the
                      value { 0 0 }."
              ::= { dot1dBasePortEntry 3 }

          dot1dBasePortDelayExceededDiscards OBJECT-TYPE
              SYNTAX  Counter



Decker, Langille, Rijsinghani & McCloghrie                     [Page 13]

RFC 1493                       Bridge MIB                      July 1993


              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of frames discarded by this port due
                      to excessive transit delay through the bridge.  It
                      is incremented by both transparent and source
                      route bridges."
              REFERENCE
                       "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dBasePortEntry 4 }

          dot1dBasePortMtuExceededDiscards OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of frames discarded by this port due
                      to an excessive size.  It is incremented by both
                      transparent and source route bridges."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dBasePortEntry 5 }


          -- the dot1dStp group

          -- Implementation of the dot1dStp group is optional.  It is
          -- implemented by those bridges that support the Spanning Tree
          -- Protocol.


          dot1dStpProtocolSpecification OBJECT-TYPE
              SYNTAX  INTEGER {
                          unknown(1),
                          decLb100(2),
                          ieee8021d(3)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "An indication of what version of the Spanning
                      Tree Protocol is being run.  The value
                      'decLb100(2)' indicates the DEC LANbridge 100
                      Spanning Tree protocol.  IEEE 802.1d
                      implementations will return 'ieee8021d(3)'.  If
                      future versions of the IEEE Spanning Tree Protocol
                      are released that are incompatible with the
                      current version a new value will be defined."



Decker, Langille, Rijsinghani & McCloghrie                     [Page 14]

RFC 1493                       Bridge MIB                      July 1993


              ::= { dot1dStp 1 }

          dot1dStpPriority OBJECT-TYPE
              SYNTAX  INTEGER (0..65535)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value of the write-able portion of the Bridge
                      ID, i.e., the first two octets of the (8 octet
                      long) Bridge ID.  The other (last) 6 octets of the
                      Bridge ID are given by the value of
                      dot1dBaseBridgeAddress."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.7"
              ::= { dot1dStp 2 }

          dot1dStpTimeSinceTopologyChange OBJECT-TYPE
              SYNTAX  TimeTicks
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The time (in hundredths of a second) since the
                      last time a topology change was detected by the
                      bridge entity."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.8.1.1.3"
              ::= { dot1dStp 3 }

          dot1dStpTopChanges OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The total number of topology changes detected by
                      this bridge since the management entity was last
                      reset or initialized."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.8.1.1.3"
              ::= { dot1dStp 4 }

          dot1dStpDesignatedRoot OBJECT-TYPE
              SYNTAX  BridgeId
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The bridge identifier of the root of the spanning
                      tree as determined by the Spanning Tree Protocol
                      as executed by this node.  This value is used as



Decker, Langille, Rijsinghani & McCloghrie                     [Page 15]

RFC 1493                       Bridge MIB                      July 1993


                      the Root Identifier parameter in all Configuration
                      Bridge PDUs originated by this node."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.1"
              ::= { dot1dStp 5 }

          dot1dStpRootCost OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The cost of the path to the root as seen from
                      this bridge."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.2"
              ::= { dot1dStp 6 }

          dot1dStpRootPort OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port number of the port which offers the
                      lowest cost path from this bridge to the root
                      bridge."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.3"
              ::= { dot1dStp 7 }

          dot1dStpMaxAge OBJECT-TYPE
              SYNTAX  Timeout
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The maximum age of Spanning Tree Protocol
                      information learned from the network on any port
                      before it is discarded, in units of hundredths of
                      a second.  This is the actual value that this
                      bridge is currently using."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.4"
              ::= { dot1dStp 8 }

          dot1dStpHelloTime OBJECT-TYPE
              SYNTAX  Timeout
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION



Decker, Langille, Rijsinghani & McCloghrie                     [Page 16]

RFC 1493                       Bridge MIB                      July 1993


                      "The amount of time between the transmission of
                      Configuration bridge PDUs by this node on any port
                      when it is the root of the spanning tree or trying
                      to become so, in units of hundredths of a second.
                      This is the actual value that this bridge is
                      currently using."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.5"
              ::= { dot1dStp 9 }

          dot1dStpHoldTime OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This time value determines the interval length
                      during which no more than two Configuration bridge
                      PDUs shall be transmitted by this node, in units
                      of hundredths of a second."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.14"
              ::= { dot1dStp 10 }

          dot1dStpForwardDelay OBJECT-TYPE
              SYNTAX  Timeout
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "This time value, measured in units of hundredths
                      of a second, controls how fast a port changes its
                      spanning state when moving towards the Forwarding
                      state.  The value determines how long the port
                      stays in each of the Listening and Learning
                      states, which precede the Forwarding state.  This
                      value is also used, when a topology change has
                      been detected and is underway, to age all dynamic
                      entries in the Forwarding Database.  [Note that
                      this value is the one that this bridge is
                      currently using, in contrast to
                      dot1dStpBridgeForwardDelay which is the value that
                      this bridge and all others would start using
                      if/when this bridge were to become the root.]"
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.6"
              ::= { dot1dStp 11 }

          dot1dStpBridgeMaxAge OBJECT-TYPE
              SYNTAX  Timeout (600..4000)



Decker, Langille, Rijsinghani & McCloghrie                     [Page 17]

RFC 1493                       Bridge MIB                      July 1993


              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value that all bridges use for MaxAge when
                      this bridge is acting as the root.  Note that
                      802.1D-1990 specifies that the range for this
                      parameter is related to the value of
                      dot1dStpBridgeHelloTime. The granularity of this
                      timer is specified by 802.1D-1990 to be 1 second.
                      An agent may return a badValue error if a set is
                      attempted to a value which is not a whole number
                      of seconds."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.8"
              ::= { dot1dStp 12 }

          dot1dStpBridgeHelloTime OBJECT-TYPE
              SYNTAX  Timeout (100..1000)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value that all bridges use for HelloTime when
                      this bridge is acting as the root.  The
                      granularity of this timer is specified by 802.1D-
                      1990 to be 1 second.  An agent may return a
                      badValue error if a set is attempted to a value
                      which is not a whole number of seconds."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.9"
              ::= { dot1dStp 13 }

          dot1dStpBridgeForwardDelay OBJECT-TYPE
              SYNTAX  Timeout (400..3000)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value that all bridges use for ForwardDelay
                      when this bridge is acting as the root.  Note that
                      802.1D-1990 specifies that the range for this
                      parameter is related to the value of
                      dot1dStpBridgeMaxAge.  The granularity of this
                      timer is specified by 802.1D-1990 to be 1 second.
                      An agent may return a badValue error if a set is
                      attempted to a value which is not a whole number
                      of seconds."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.3.10"
              ::= { dot1dStp 14 }



Decker, Langille, Rijsinghani & McCloghrie                     [Page 18]

RFC 1493                       Bridge MIB                      July 1993


          -- The Spanning Tree Port Table

          dot1dStpPortTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dStpPortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table that contains port-specific information
                      for the Spanning Tree Protocol."
              ::= { dot1dStp 15 }

          dot1dStpPortEntry OBJECT-TYPE
              SYNTAX  Dot1dStpPortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A list of information maintained by every port
                      about the Spanning Tree Protocol state for that
                      port."
              INDEX   { dot1dStpPort }
              ::= { dot1dStpPortTable 1 }

          Dot1dStpPortEntry ::=
              SEQUENCE {
                  dot1dStpPort
                      INTEGER,
                  dot1dStpPortPriority
                      INTEGER,
                  dot1dStpPortState
                      INTEGER,
                  dot1dStpPortEnable
                      INTEGER,
                  dot1dStpPortPathCost
                      INTEGER,
                  dot1dStpPortDesignatedRoot
                      BridgeId,
                  dot1dStpPortDesignatedCost
                      INTEGER,
                  dot1dStpPortDesignatedBridge
                      BridgeId,
                  dot1dStpPortDesignatedPort
                      OCTET STRING,
                  dot1dStpPortForwardTransitions
                      Counter
              }

          dot1dStpPort OBJECT-TYPE
              SYNTAX  INTEGER (1..65535)



Decker, Langille, Rijsinghani & McCloghrie                     [Page 19]

RFC 1493                       Bridge MIB                      July 1993


              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port number of the port for which this entry
                      contains Spanning Tree Protocol management
                      information."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.8.2.1.2"
              ::= { dot1dStpPortEntry 1 }

          dot1dStpPortPriority OBJECT-TYPE
              SYNTAX  INTEGER (0..255)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The value of the priority field which is
                      contained in the first (in network byte order)
                      octet of the (2 octet long) Port ID.  The other
                      octet of the Port ID is given by the value of
                      dot1dStpPort."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.1"
              ::= { dot1dStpPortEntry 2 }

          dot1dStpPortState OBJECT-TYPE
              SYNTAX  INTEGER {
                          disabled(1),
                          blocking(2),
                          listening(3),
                          learning(4),
                          forwarding(5),
                          broken(6)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port's current state as defined by
                      application of the Spanning Tree Protocol.  This
                      state controls what action a port takes on
                      reception of a frame.  If the bridge has detected
                      a port that is malfunctioning it will place that
                      port into the broken(6) state.  For ports which
                      are disabled (see dot1dStpPortEnable), this object
                      will have a value of disabled(1)."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.2"
              ::= { dot1dStpPortEntry 3 }




Decker, Langille, Rijsinghani & McCloghrie                     [Page 20]

RFC 1493                       Bridge MIB                      July 1993


          dot1dStpPortEnable OBJECT-TYPE
              SYNTAX  INTEGER {
                          enabled(1),
                          disabled(2)
                      }
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The enabled/disabled status of the port."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.2"
              ::= { dot1dStpPortEntry 4 }

          dot1dStpPortPathCost OBJECT-TYPE
              SYNTAX  INTEGER (1..65535)
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The contribution of this port to the path cost of
                      paths towards the spanning tree root which include
                      this port.  802.1D-1990 recommends that the
                      default value of this parameter be in inverse
                      proportion to the speed of the attached LAN."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.3"
              ::= { dot1dStpPortEntry 5 }

          dot1dStpPortDesignatedRoot OBJECT-TYPE
              SYNTAX  BridgeId
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The unique Bridge Identifier of the Bridge
                      recorded as the Root in the Configuration BPDUs
                      transmitted by the Designated Bridge for the
                      segment to which the port is attached."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.4"
              ::= { dot1dStpPortEntry 6 }

          dot1dStpPortDesignatedCost OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The path cost of the Designated Port of the
                      segment connected to this port.  This value is
                      compared to the Root Path Cost field in received



Decker, Langille, Rijsinghani & McCloghrie                     [Page 21]

RFC 1493                       Bridge MIB                      July 1993


                      bridge PDUs."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.5"
              ::= { dot1dStpPortEntry 7 }

          dot1dStpPortDesignatedBridge OBJECT-TYPE
              SYNTAX  BridgeId
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The Bridge Identifier of the bridge which this
                      port considers to be the Designated Bridge for
                      this port's segment."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.6"
              ::= { dot1dStpPortEntry 8 }

          dot1dStpPortDesignatedPort OBJECT-TYPE
              SYNTAX  OCTET STRING (SIZE (2))
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The Port Identifier of the port on the Designated
                      Bridge for this port's segment."
              REFERENCE
                      "IEEE 802.1D-1990: Section 4.5.5.7"
              ::= { dot1dStpPortEntry 9 }

          dot1dStpPortForwardTransitions OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of times this port has transitioned
                      from the Learning state to the Forwarding state."
              ::= { dot1dStpPortEntry 10 }


          -- the dot1dTp group

          -- Implementation of the dot1dTp group is optional.  It is
          -- implemented by those bridges that support the transparent
          -- bridging mode.  A transparent or SRT bridge will implement
          -- this group.


          dot1dTpLearnedEntryDiscards OBJECT-TYPE
              SYNTAX  Counter



Decker, Langille, Rijsinghani & McCloghrie                     [Page 22]

RFC 1493                       Bridge MIB                      July 1993


              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The total number of Forwarding Database entries,
                      which have been or would have been learnt, but
                      have been discarded due to a lack of space to
                      store them in the Forwarding Database.  If this
                      counter is increasing, it indicates that the
                      Forwarding Database is regularly becoming full (a
                      condition which has unpleasant performance effects
                      on the subnetwork).  If this counter has a
                      significant value but is not presently increasing,
                      it indicates that the problem has been occurring
                      but is not persistent."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.7.1.1.3"
              ::= { dot1dTp 1 }

          dot1dTpAgingTime OBJECT-TYPE
              SYNTAX   INTEGER (10..1000000)
              ACCESS   read-write
              STATUS   mandatory
              DESCRIPTION
                      "The timeout period in seconds for aging out
                      dynamically learned forwarding information.
                      802.1D-1990 recommends a default of 300 seconds."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.7.1.1.3"
              ::= { dot1dTp 2 }


          --  The Forwarding Database for Transparent Bridges

          dot1dTpFdbTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dTpFdbEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table that contains information about unicast
                      entries for which the bridge has forwarding and/or
                      filtering information.  This information is used
                      by the transparent bridging function in
                      determining how to propagate a received frame."
              ::= { dot1dTp 3 }

          dot1dTpFdbEntry OBJECT-TYPE
              SYNTAX  Dot1dTpFdbEntry
              ACCESS  not-accessible



Decker, Langille, Rijsinghani & McCloghrie                     [Page 23]

RFC 1493                       Bridge MIB                      July 1993


              STATUS  mandatory
              DESCRIPTION
                      "Information about a specific unicast MAC address
                      for which the bridge has some forwarding and/or
                      filtering information."
              INDEX   { dot1dTpFdbAddress }
              ::= { dot1dTpFdbTable 1 }

          Dot1dTpFdbEntry ::=
              SEQUENCE {
                  dot1dTpFdbAddress
                      MacAddress,
                  dot1dTpFdbPort
                      INTEGER,
                  dot1dTpFdbStatus
                      INTEGER
              }

          dot1dTpFdbAddress OBJECT-TYPE
              SYNTAX  MacAddress
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "A unicast MAC address for which the bridge has
                      forwarding and/or filtering information."
              REFERENCE
                      "IEEE 802.1D-1990: Section 3.9.1, 3.9.2"
              ::= { dot1dTpFdbEntry 1 }

          dot1dTpFdbPort OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "Either the value '0', or the port number of the
                      port on which a frame having a source address
                      equal to the value of the corresponding instance
                      of dot1dTpFdbAddress has been seen.  A value of
                      '0' indicates that the port number has not been
                      learned but that the bridge does have some
                      forwarding/filtering information about this
                      address (e.g. in the dot1dStaticTable).
                      Implementors are encouraged to assign the port
                      value to this object whenever it is learned even
                      for addresses for which the corresponding value of
                      dot1dTpFdbStatus is not learned(3)."
              ::= { dot1dTpFdbEntry 2 }




Decker, Langille, Rijsinghani & McCloghrie                     [Page 24]

RFC 1493                       Bridge MIB                      July 1993


          dot1dTpFdbStatus OBJECT-TYPE
              SYNTAX  INTEGER {
                          other(1),
                          invalid(2),
                          learned(3),
                          self(4),
                          mgmt(5)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The status of this entry.  The meanings of the
                      values are:

                        other(1)   : none of the following.  This would
                                     include the case where some other
                                     MIB object (not the corresponding
                                     instance of dot1dTpFdbPort, nor an
                                     entry in the dot1dStaticTable) is
                                     being used to determine if and how
                                     frames addressed to the value of
                                     the corresponding instance of
                                     dot1dTpFdbAddress are being
                                     forwarded.

                        invalid(2) : this entry is not longer valid
                                     (e.g., it was learned but has since
                                     aged-out), but has not yet been
                                     flushed from the table.

                        learned(3) : the value of the corresponding
                                     instance of dot1dTpFdbPort was
                                     learned, and is being used.

                        self(4)    : the value of the corresponding
                                     instance of dot1dTpFdbAddress
                                     represents one of the bridge's
                                     addresses.  The corresponding
                                     instance of dot1dTpFdbPort
                                     indicates which of the bridge's
                                     ports has this address.

                        mgmt(5)    : the value of the corresponding
                                     instance of dot1dTpFdbAddress is
                                     also the value of an existing
                                     instance of dot1dStaticAddress."
              ::= { dot1dTpFdbEntry 3 }




Decker, Langille, Rijsinghani & McCloghrie                     [Page 25]

RFC 1493                       Bridge MIB                      July 1993


          --  Port Table for Transparent Bridges

          dot1dTpPortTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dTpPortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table that contains information about every
                      port that is associated with this transparent
                      bridge."
              ::= { dot1dTp 4 }

          dot1dTpPortEntry OBJECT-TYPE
              SYNTAX  Dot1dTpPortEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A list of information for each port of a
                      transparent bridge."
              INDEX   { dot1dTpPort }
              ::= { dot1dTpPortTable 1 }

          Dot1dTpPortEntry ::=
              SEQUENCE {
                  dot1dTpPort
                      INTEGER,
                  dot1dTpPortMaxInfo
                      INTEGER,
                  dot1dTpPortInFrames
                      Counter,
                  dot1dTpPortOutFrames
                      Counter,
                  dot1dTpPortInDiscards
                      Counter
              }

          dot1dTpPort OBJECT-TYPE
              SYNTAX  INTEGER (1..65535)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The port number of the port for which this entry
                      contains Transparent bridging management
                      information."
              ::= { dot1dTpPortEntry 1 }

          -- It would be nice if we could use ifMtu as the size of the
          -- largest INFO field, but we can't because ifMtu is defined



Decker, Langille, Rijsinghani & McCloghrie                     [Page 26]

RFC 1493                       Bridge MIB                      July 1993


          -- to be the size that the (inter-)network layer can use which
          -- can differ from the MAC layer (especially if several layers
          -- of encapsulation are used).

          dot1dTpPortMaxInfo OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The maximum size of the INFO (non-MAC) field that
                      this port will receive or transmit."
              ::= { dot1dTpPortEntry 2 }

          dot1dTpPortInFrames OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of frames that have been received by
                      this port from its segment. Note that a frame
                      received on the interface corresponding to this
                      port is only counted by this object if and only if
                      it is for a protocol being processed by the local
                      bridging function, including bridge management
                      frames."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dTpPortEntry 3 }

          dot1dTpPortOutFrames OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of frames that have been transmitted
                      by this port to its segment.  Note that a frame
                      transmitted on the interface corresponding to this
                      port is only counted by this object if and only if
                      it is for a protocol being processed by the local
                      bridging function, including bridge management
                      frames."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dTpPortEntry 4 }

          dot1dTpPortInDiscards OBJECT-TYPE
              SYNTAX   Counter
              ACCESS   read-only



Decker, Langille, Rijsinghani & McCloghrie                     [Page 27]

RFC 1493                       Bridge MIB                      July 1993


              STATUS   mandatory
              DESCRIPTION
                      "Count of valid frames received which were
                      discarded (i.e., filtered) by the Forwarding
                      Process."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.6.1.1.3"
              ::= { dot1dTpPortEntry 5 }


          -- The Static (Destination-Address Filtering) Database

          -- Implementation of this group is optional.


          dot1dStaticTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF Dot1dStaticEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A table containing filtering information
                      configured into the bridge by (local or network)
                      management specifying the set of ports to which
                      frames received from specific ports and containing
                      specific destination addresses are allowed to be
                      forwarded.  The value of zero in this table as the
                      port number from which frames with a specific
                      destination address are received, is used to
                      specify all ports for which there is no specific
                      entry in this table for that particular
                      destination address.  Entries are valid for
                      unicast and for group/broadcast addresses."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.7.2"
              ::= { dot1dStatic 1 }

          dot1dStaticEntry OBJECT-TYPE
              SYNTAX  Dot1dStaticEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "Filtering information configured into the bridge
                      by (local or network) management specifying the
                      set of ports to which frames received from a
                      specific port and containing a specific
                      destination address are allowed to be forwarded."
              REFERENCE
                      "IEEE 802.1D-1990: Section 6.7.2"



Decker, Langille, Rijsinghani & McCloghrie                     [Page 28]

RFC 1493                       Bridge MIB                      July 1993


              INDEX   { dot1dStaticAddress, dot1dStaticReceivePort }
              ::= { dot1dStaticTable 1 }

          Dot1dStaticEntry ::=
              SEQUENCE {
                  dot1dStaticAddress
                      MacAddress,
                  dot1dStaticReceivePort
                      INTEGER,
                  dot1dStaticAllowedToGoTo
                      OCTET STRING,
                  dot1dStaticStatus
                      INTEGER
              }

          dot1dStaticAddress OBJECT-TYPE
              SYNTAX  MacAddress
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The destination MAC address in a frame to which
                      this entry's filtering information applies.  This
                      object can take the value of a unicast address, a
                      group address or the broadcast address."
              REFERENCE
                      "IEEE 802.1D-1990: Section 3.9.1, 3.9.2"
              ::= { dot1dStaticEntry 1 }

          dot1dStaticReceivePort OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "Either the value '0', or the port number of the
                      port from which a frame must be received in order
                      for this entry's filtering information to apply.
                      A value of zero indicates that this entry applies
                      on all ports of the bridge for which there is no
                      other applicable entry."
              ::= { dot1dStaticEntry 2 }

          dot1dStaticAllowedToGoTo OBJECT-TYPE
              SYNTAX  OCTET STRING
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The set of ports to which frames received from a
                      specific port and destined for a specific MAC



Decker, Langille, Rijsinghani & McCloghrie                     [Page 29]

RFC 1493                       Bridge MIB                      July 1993


                      address, are allowed to be forwarded.  Each octet
                      within the value of this object specifies a set of
                      eight ports, with the first octet specifying ports
                      1 through 8, the second octet specifying ports 9
                      through 16, etc.  Within each octet, the most
                      significant bit represents the lowest numbered
                      port, and the least significant bit represents the
                      highest numbered port.  Thus, each port of the
                      bridge is represented by a single bit within the
                      value of this object.  If that bit has a value of
                      '1' then that port is included in the set of
                      ports; the port is not included if its bit has a
                      value of '0'.  (Note that the setting of the bit
                      corresponding to the port from which a frame is
                      received is irrelevant.)  The default value of
                      this object is a string of ones of appropriate
                      length."
              ::= { dot1dStaticEntry 3 }

          dot1dStaticStatus OBJECT-TYPE
              SYNTAX  INTEGER {
                          other(1),
                          invalid(2),
                          permanent(3),
                          deleteOnReset(4),
                          deleteOnTimeout(5)
                      }
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "This object indicates the status of this entry.
                      The default value is permanent(3).

                           other(1) - this entry is currently in use but
                                the conditions under which it will
                                remain so are different from each of the
                                following values.
                           invalid(2) - writing this value to the object
                                removes the corresponding entry.
                           permanent(3) - this entry is currently in use
                                and will remain so after the next reset
                                of the bridge.
                           deleteOnReset(4) - this entry is currently in
                                use and will remain so until the next
                                reset of the bridge.
                           deleteOnTimeout(5) - this entry is currently
                                in use and will remain so until it is
                                aged out."



Decker, Langille, Rijsinghani & McCloghrie                     [Page 30]

RFC 1493                       Bridge MIB                      July 1993


              ::= { dot1dStaticEntry 4 }


          -- Traps for use by Bridges

          -- Traps for the Spanning Tree Protocol

          newRoot TRAP-TYPE
              ENTERPRISE  dot1dBridge
              DESCRIPTION
                      "The newRoot trap indicates that the sending agent
                      has become the new root of the Spanning Tree; the
                      trap is sent by a bridge soon after its election
                      as the new root, e.g., upon expiration of the
                      Topology Change Timer immediately subsequent to
                      its election.  Implementation of this trap is
                      optional."
              ::= 1

          topologyChange TRAP-TYPE
              ENTERPRISE  dot1dBridge
              DESCRIPTION
                      "A topologyChange trap is sent by a bridge when
                      any of its configured ports transitions from the
                      Learning state to the Forwarding state, or from
                      the Forwarding state to the Blocking state.  The
                      trap is not sent if a newRoot trap is sent for the
                      same transition.  Implementation of this trap is
                      optional."
              ::= 2

          END

6.  Acknowledgments

   This document was produced on behalf of the Bridge Sub-Working Group
   of the SNMP Working Group of the Internet Engineering Task Force.
   Over the course of its deliberations, the working group received four
   separate documents for consideration as the basis for its work.  The
   first was submitted by Stan Froyd of Advanced Computer
   Communications; the second by Richard Fox of SynOptics; the third by
   Eric Decker of cisco Inc. and Keith McCloghrie of Hughes LAN Systems;
   and the fourth by Paul Langille and Anil Rijsinghani of Digital
   Equipment Corp. After considering the submissions, the working group
   chose to proceed with a document formed as a conjunction of the
   latter two submissions.  This document is the result.





Decker, Langille, Rijsinghani & McCloghrie                     [Page 31]

RFC 1493                       Bridge MIB                      July 1993


   The authors wish to thank the members of the Bridge Working Group for
   their many comments and suggestions which improved this effort. In
   particular, Fred Baker (chairman of the working group) of ACC, Steve
   Sherry of Xyplex, and Frank Kastenholz of Clearpoint Research Corp.
   Others members of the Bridge Working Group who contributed to this
   effort are:

               Bill Anderson, Mitre
               Karl Auerbach, Epilogue
               Fred Baker, ACC (chair)
               Terry Bradley, Wellfleet
               Ted Brunner, Bellcore
               Jeffrey Buffum, Apollo
               Chris ChioTasso, Fibronics
               Anthony Chung, HLS
               Chuck Davin, MIT-LCS
               Andy Davis, Spider
               Eric Decker, cisco
               Nadya El-Afandi, Network Systems
               Gary Ellis,HP/Apollo
               Richard Fox, SynOptics
               Stan Froyd, ACC
               Frank Kastenholz, Clearpoint Research
               Shirnshon Kaufman,
               Jim Kinder, Fibercom
               Cheryl Krupczak,NCR
               Paul Langille, Digital
               Peter Lin,Vitalink
               Keith McCloghrie, HLS
               Donna McMaster, SynOptics
               Dave Perkins, 3Com
               Jim Reinstedler, Ungermann Bass
               Anil Rijsinghani, Digital
               Mark Schaefer, David Systems
               Steve Sherry, Xyplex
               Bob Stewart, Xyplex
               Emil Sturniolo,
               Kevin Synott, Retix
               Ian Thomas, Chipcom
               Maurice Turcott, Racal
               Fei Xu,










Decker, Langille, Rijsinghani & McCloghrie                     [Page 32]

RFC 1493                       Bridge MIB                      July 1993


7.  References

   [1] Cerf, V., "IAB Recommendations for the Development of Internet
       Network Management Standards", RFC 1052, NRI, April 1988.

   [2] Cerf, V., "Report of the Second Ad Hoc Network Management Review
       Group", RFC 1109, NRI, August 1989.

   [3] Rose M., and K. McCloghrie, "Structure and Identification of
       Management Information for TCP/IP-based internets", STD 16, RFC
       1155, Performance Systems International, Hughes LAN Systems, May
       1990.

   [4] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple
       Network Management Protocol", STD 15, RFC 1157, SNMP Research,
       Performance Systems International, Performance Systems
       International, MIT Laboratory for Computer Science, May 1990.

   [5] McCloghrie K., and M. Rose, Editors, "Management Information Base
       for Network Management of TCP/IP-based internets", STD 17, RFC
       1213, Performance Systems International, March 1991.

   [6] Information processing systems - Open Systems Interconnection -
       Specification of Abstract Syntax Notation One (ASN.1),
       International Organization for Standardization, International
       Standard 8824, December 1987.

   [7] Information processing systems - Open Systems Interconnection -
       Specification of Basic Encoding Rules for Abstract Notation One
       (ASN.1), International Organization for Standardization,
       International Standard 8825, December 1987.

   [8] Rose, M., and K. McCloghrie, Editors, "Concise MIB Definitions",
       STD 16, RFC 1212, Performance Systems International, Hughes LAN
       Systems, March 1991.

   [9] Rose, M., Editor, "A Convention for Defining Traps for use with
       the SNMP", RFC 1215, Performance Systems International, March
       1991.

  [10] ANSI/IEEE Standard 802.1D-1990 MAC Bridges, IEEE Project 802
       Local and Metropolitan Area Networks, (March 8, 1991).

  [11] ISO DIS 10038 MAC Bridges.

8.  Security Considerations

   Security issues are not discussed in this memo.



Decker, Langille, Rijsinghani & McCloghrie                     [Page 33]

RFC 1493                       Bridge MIB                      July 1993


9.  Authors' Addresses

   Eric B. Decker
   cisco Systems, Inc.
   1525 O'Brien Dr.
   Menlo Park, CA  94025

   Phone: (415) 326-1941
   Email: cire@cisco.com


   Paul Langille
   Digital Equipment Corporation
   Digital Drive, MK02-2/K03
   Merrimack, NH 03054

   Phone: (603) 884-4045
   EMail: langille@edwin.enet.dec.com


   Anil Rijsinghani
   Digital Equipment Corporation
   550 King Street
   Littleton, MA 01460

   Phone: (508) 486-6786
   EMail: anil@levers.enet.dec.com


   Keith McCloghrie
   Hughes LAN Systems, Inc.
   1225 Charleston Road
   Mountain View, CA 94043

   Phone: (415) 966-7934
   EMail: kzm@hls.com















Decker, Langille, Rijsinghani & McCloghrie                     [Page 34]