File: rfc2889.txt

package info (click to toggle)
doc-rfc 20170121-1
  • links: PTS, VCS
  • area: non-free
  • in suites: stretch
  • size: 541,932 kB
  • ctags: 32
  • sloc: xml: 267,963; sh: 101; python: 90; perl: 42; makefile: 13
file content (1963 lines) | stat: -rw-r--r-- 73,251 bytes parent folder | download | duplicates (6)
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
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963






Network Working Group                                      R. Mandeville
Request for Comments: 2889                                     CQOS Inc.
Category: Informational                                        J. Perser
                                                  Spirent Communications
                                                             August 2000


           Benchmarking Methodology for LAN Switching Devices

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

Table of Contents

   1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . .  2
   3. Test setup . . . . . . . . . . . . . . . . . . . . . . . . . .  2
   4. Frame formats and sizes  . . . . . . . . . . . . . . . . . . .  3
   5. Benchmarking Tests . . . . . . . . . . . . . . . . . . . . . .  3
      5.1  Fully meshed throughput, frame loss and forwarding rates   4
      5.2  Partially meshed one-to-many/many-to-one  . . . . . . . .  7
      5.3  Partially meshed multiple devices . . . . . . . . . . . . 10
      5.4  Partially meshed unidirectional traffic . . . . . . . . . 13
      5.5  Congestion Control  . . . . . . . . . . . . . . . . . . . 16
      5.6  Forward Pressure and Maximum Forwarding Rate  . . . . . . 19
      5.7  Address caching capacity  . . . . . . . . . . . . . . . . 22
      5.8  Address learning rate . . . . . . . . . . . . . . . . . . 25
      5.9  Errored frames filtering. . . . . . . . . . . . . . . . . 27
      5.10 Broadcast frame Forwarding and Latency  . . . . . . . . . 28
   6. Security Considerations  . . . . . . . . . . . . . . . . . . . 30
   7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 30
   8. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 30
      Appendix A: Formulas . . . . . . . . . . . . . . . . . . . . . 31
      Appendix B: Generating Offered Load  . . . . . . . . . . . . . 32
      Full Copyright Statement . . . . . . . . . . . . . . . . . . . 35









Mandeville & Perser          Informational                      [Page 1]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


1. Introduction

   This document is intended to provide methodology for the benchmarking
   of local area network (LAN) switching devices.  It extends the
   methodology already defined for benchmarking network interconnecting
   devices in RFC 2544 [3] to switching devices.

   This RFC primarily deals with devices which switch frames at the
   Medium Access Control (MAC) layer. It provides a methodology for
   benchmarking switching devices, forwarding performance, congestion
   control, latency, address handling and filtering. In addition to
   defining the tests, this document also describes specific formats for
   reporting the results of the tests.

   A previous document, "Benchmarking Terminology for LAN Switching
   Devices" [2], defined many of the terms that are used in this
   document.  The terminology document SHOULD be consulted before
   attempting to make use of this document.

2. Requirements

   The following RFCs SHOULD be consulted before attempting to make use
   of this document: RFC 1242 [1], RFC 2285 [2], and RFC 2544 [3].

   For the sake of clarity and continuity, this RFC adopts the template
   for benchmarking tests set out in Section 26 of RFC 2544.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.

3. Test setup

   This document extends the general test setup described in section 6
   of RFC 2544 [3] to the benchmarking of LAN switching devices.  RFC
   2544 [3] primarily describes non-meshed traffic where input and
   output interfaces  are grouped in mutually exclusive sending and
   receiving pairs.  In fully meshed traffic, each interface of a
   DUT/SUT is set up to both receive and transmit frames to all the
   other interfaces under test.

   Prior to each test run, the DUT/SUT MUST learn the MAC addresses used
   in the test and the address learning SHOULD be verified.  Addresses
   not learned will be forwarded as flooded frames and reduce the amount
   of correctly forwarded frames.  The rate at which address learning
   frames are offered may have to be adjusted to be as low as 50 frames
   per second or even less, to guarantee successful learning.  The
   DUT/SUT address aging time SHOULD be configured to be greater than



Mandeville & Perser          Informational                      [Page 2]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   the period of the learning phase of the test plus the trial duration
   plus any configuration time required by the testing device.
   Addresses SHOULD NOT age out until the trial duration is completed.
   More than one learning trial may be needed for the association of the
   address to the port to occur.

   If a DUT/SUT uses a hashing algorithm with address learning, the
   DUT/SUT may not learn the necessary addresses to perform the tests.
   The format of the MAC addresses MUST be adjustable so that the
   address mapping may be re-arranged to ensure that the DUT/SUT learns
   all the addresses.

4.  Frame formats and sizes

   The test frame format is defined in RFC 2544 section 8 [3] and MUST
   contain a unique signature field located in the UDP DATA area of the
   Test Frame (see Appendix C [3]).  The purpose of the signature field
   is filter out frames that are not part of the offered load.

   The signature field MUST be unique enough to identify the frames not
   originating from the DUT/SUT.  The signature field SHOULD be located
   after byte 56 (collision window [4] ) or at the end of the frame. The
   length, contents and method of detection is not defined in this memo.

   The signature field MAY have a unique identifier per port.  This
   would filter out misforwarded frames.  It is possible for a DUT/SUT
   to strip off the MAC layer, send it through its switching matrix, and
   transmit it out with the correct destination MAC address but the
   wrong payload.

   For frame sizes, refer to RFC 2544, section 9 [3].

   There are three possible frame formats for layer 2 Ethernet switches:
   standard MAC Ethernet frames, standard MAC Ethernet frames with
   vendor-specific tags added to them, and IEEE 802.3ac frames tagged to
   accommodate 802.1p&Q.  The two types of tagged frames may exceed the
   standard maximum length frame of 1518 bytes, and may not be accepted
   by the interface controllers of some DUT/SUTs. It is recommended to
   check the compatibility of the DUT/SUT with tagged frames before
   testing.

   Devices switching tagged frames of over 1518 bytes will have a
   different maximum forwarding rate than untagged frames.

5. Benchmarking Tests

   The following tests offer objectives, procedures, and reporting
   formats for benchmarking LAN switching devices.



Mandeville & Perser          Informational                      [Page 3]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.1  Fully meshed throughput, frame loss and forwarding rates

5.1.1 Objective

   To determine the throughput, frame loss and forwarding rates of
   DUT/SUTs offered fully meshed traffic as defined in RFC 2285 [2].

5.1.2 Setup Parameters

   When offering full meshed traffic, the following parameters MUST be
   defined.  Each parameter is configured with the following
   considerations.

      Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
      1280 and 1518 bytes, per RFC 2544 section 9 [3].  The four CRC
      bytes are included in the frame size specified.

      Interframe Gap (IFG) - The IFG between frames inside a burst MUST
      be at the minimum specified by the standard (9.6 us for 10Mbps
      Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1 Gbps
      Ethernet) of the medium being tested.

      Duplex mode - Half duplex or full duplex.

      ILoad - Intended Load per port is expressed in a percentage of the
      medium's maximum theoretical load, regardless of traffic
      orientation or duplex mode.  Certain test configurations will
      theoretically over-subscribe the DUT/SUT.

      In half duplex, an ILoad over 50% will over-subscribe the DUT/SUT.

      Burst Size - The burst size defines the number of frames sent
      back-to-back at the minimum legal IFG [4] before pausing
      transmission to receive frames.  Burst sizes SHOULD vary between 1
      and 930 frames.  A burst size of 1 will simulate constant load
      [1].

      Addresses per port - Represents the number of addresses which are
      being tested for each port.  Number of addresses SHOULD be a
      binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
      Recommended value is 1.

      Trial Duration - The recommended Trial Duration is 30 seconds.
      Trial duration SHOULD be adjustable between 1 and 300 seconds.







Mandeville & Perser          Informational                      [Page 4]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.1.3 Procedure

   All ports on the tester MUST transmit test frames either in a Frame
   Based or Time Based mode (Appendix B).  All ports SHOULD start
   transmitting their frames within 1% of the trial duration.  For a
   trial duration of 30 seconds, all ports SHOULD have started
   transmitting frames within 300 milliseconds of each other.

   Each port in the test MUST send test frames to all other ports in a
   round robin type fashion.  The sequence of addresses MUST NOT change
   when congestion control is applied.  The following table shows how
   each port in a test MUST transmit test frames to all other ports in
   the test.  In this example, there are six ports with 1 address per
   port:

   Source Port       Destination Ports (in order of transmission)

   Port #1           2       3       4       5       6       2...
   Port #2           3       4       5       6       1       3...
   Port #3           4       5       6       1       2       4...
   Port #4           5       6       1       2       3       5...
   Port #5           6       1       2       3       4       6...
   Port #6           1       2       3       4       5       1...

   As shown in the table, there is an equal distribution of destination
   addresses for each transmit opportunity. This keeps the test balanced
   so that one destination port is not overloaded by the test algorithm
   and all ports are equally and fully loaded throughout the test.  Not
   following this algorithm exactly will produce inconsistent results.

   For tests using multiple addresses per port, the actual port
   destinations are the same as described above and the actual
   source/destination address pairs SHOULD be chosen randomly to
   exercise the DUT/SUT's ability to perform address lookups.

   For every address, learning frames MUST be sent to the DUT/SUT to
   allow the DUT/SUT update its address tables properly.

5.1.4 Measurements

   Each port should receive the same number of test frames that it
   transmitted.  Each receiving port MUST categorize, then count the
   frames into one of two groups:

      1.) Received Frames: received frames MUST have the correct
          destination MAC address and SHOULD match a signature field.

      2.) Flood count [2].



Mandeville & Perser          Informational                      [Page 5]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   Any frame originating from the DUT/SUT (spanning tree, SNMP, RIP,
    ...) MUST not be counted as a received frame.  Frames originating
   from the DUT/SUT MAY be counted as flooded frames or not counted at
   all.

   Frame loss rate of the DUT/SUT SHOULD be reported as defined in
   section 26.3 [3] with the following notes: Frame loss rate SHOULD be
   measured at the end of the trail duration.  The term "rate", for this
   measurement only, does not imply the units in the fashion of "per
   second."

5.1.4.1 Throughput

   Throughput measurement is defined in section 26.1 [3].  A search
   algorithm is employed to find the maximum Oload [2] with a zero Frame
   loss rate [1].  The algorithm MUST adjust Iload to find the
   throughput.

5.1.4.2 Forwarding Rate

   Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
   of test frames per second that the device is observed to successfully
   forward to the correct destination interface in response to a
   specified Oload.  The Oload MUST also be cited.

   Forwarding rate at maximum offered load (FRMOL) MUST be reported as
   the number of test frames per second that a device can successfully
   transmit to the correct destination interface in response to the MOL
   as defined in section 3.6 [2]. The MOL MUST also be cited.

   Maximum forwarding rate (MFR) MUST be reported as the highest
   forwarding rate of a DUT/SUT taken from an iterative set of
   forwarding rate measurements.  The iterative set of forwarding rate
   measurements are made by adjusting Iload.  The Oload applied to the
   device MUST also be cited.

5.1.5 Reporting format

   The results for these tests SHOULD be reported in the form of a
   graph.  The x coordinate SHOULD be the frame size, the y coordinate
   SHOULD be the test results.  There SHOULD be at least two lines on
   the graph, one plotting the theoretical and one plotting the test
   results.

   To measure the DUT/SUT's ability to switch traffic while performing
   many different address lookups, the number of addresses per port MAY
   be increased in a series of tests.




Mandeville & Perser          Informational                      [Page 6]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.2  Partially meshed one-to-many/many-to-one

5.2.1 Objective

   To determine the throughput when transmitting from/to multiple ports
   and to/from one port. As with the fully meshed throughput test, this
   test is a measure of the capability of the DUT to switch frames
   without frame loss.  Results of this test can be used to determine
   the ability of the DUT to utilize an Ethernet port when switching
   traffic from multiple Ethernet ports.

5.2.2 Setup Parameters

   When offering bursty meshed traffic, the following parameters MUST be
   defined.  Each parameter is configured with the following
   considerations.

      Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
      1280 and 1518 bytes, per RFC 2544 section 9 [3].  The four CRC
      bytes are included in the frame size specified.

      Traffic Direction - Traffic can be generated in one direction, the
      reverse direction, or both directions.

      Interframe Gap (IFG) - The IFG between frames inside a burst MUST
      be at the minimum specified by the standard (9.6 us for 10Mbps
      Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1 Gbps
      Ethernet) of the medium being tested.

      Duplex mode - Half duplex or full duplex.

      ILoad - Intended Load per port is expressed in a percentage of the
      medium's maximum theoretical load, regardless of traffic
      orientation or duplex mode.  Certain test configurations will
      theoretically over-subscribe the DUT/SUT.

      In half duplex bidirectional traffic, an ILoad over 50% will
      over-subscribe the DUT/SUT.

      Burst Size - The burst size defines the number of frames sent
      back-to-back at the minimum legal IFG [4] before pausing
      transmission to receive frames.  Burst sizes SHOULD vary between 1
      and 930 frames.  A burst size of 1 will simulate constant load
      [1].







Mandeville & Perser          Informational                      [Page 7]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


      Addresses per port - Represents the number of addresses which are
      being tested for each port.  Number of addresses SHOULD be a
      binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
      Recommended value is 1.

      Trial Duration - The recommended Trial Duration is 30 seconds.
      Trial duration SHOULD be adjustable between 1 and 300 seconds.

5.2.3 Procedure

   All ports on the tester MUST transmit test frames either in a Frame
   Based or Time Based mode (Appendix B).  Depending upon traffic
   direction, some or all of the ports will be transmitting.  All ports
   SHOULD start transmitting their frames within 1% of the trial
   duration.  For a trial duration of 30 seconds, all ports SHOULD have
   started transmitting frames within 300 milliseconds of each other.

   Test frames transmitted from the Many Ports MUST be destined to the
   One port.  Test frames transmitted from the One Port MUST be destined
   to the Many ports in a round robin type fashion.  See section 5.1.3
   for a description of the round robin fashion.

   For tests using multiple addresses per port, the actual port
   destinations are the same as described above and the actual
   source/destination address pairs SHOULD be chosen randomly to
   exercise the DUT/SUT's ability to perform address lookups.

        +----------+
        |          |
        |   Many   | <--------
        |          |          \
        +----------+           \
                                \
        +----------+             \               +-------------+
        |          |              ------------>  |             |
        |   Many   |  <----------------------->  |     One     |
        |          |              ------------>  |             |
        +----------+             /               +-------------+
                                /
        +----------+           /
        |          |          /
        |   Many   |  <-------
        |          |
        +----------+

   For every address, the testing device MUST send learning frames to
   allow the DUT/SUT to update its address tables properly.




Mandeville & Perser          Informational                      [Page 8]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.2.4 Measurements

   Each receiving port MUST categorize, then count the frames into one
   of two groups:

      1.) Received Frames: received frames MUST have the correct
          destination MAC address and SHOULD match a signature field.

      2.) Flood count [2].

   Any frame originating from the DUT/SUT MUST not be counted as a
   received frame.  Frames originating from the DUT/SUT MAY be counted
   as flooded frames or not counted at all.

   Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
   of test frames per second that the device is observed to successfully
   transmit to the correct destination interface in response to a
   specified Oload.  The Oload MUST also be cited.

   Forwarding rate at maximum offered load (FRMOL) MUST be reported as
   the number of test frames per second that a device can successfully
   transmit to the correct destination interface in response to the MOL
   as defined in section 3.6 [2]. The MOL MUST also be cited.

   Maximum forwarding rate (MFR) MUST be reported as the highest
   forwarding rate of a DUT/SUT taken from an iterative set of
   forwarding rate measurements.  The iterative set of forwarding rate
   measurements are made by adjusting Iload.  The Oload applied to the
   device MUST also be cited.

5.2.5 Reporting Format

   The results for these tests SHOULD be reported in the form of a
   graph.  The x coordinate SHOULD be the frame size, the y coordinate
   SHOULD be the test results.  There SHOULD be at least two lines on
   the graph, one plotting the theoretical and one plotting the test
   results.

   To measure the DUT/SUT's ability to switch traffic while performing
   many different address lookups, the number of addresses per port MAY
   be increased in a series of tests.










Mandeville & Perser          Informational                      [Page 9]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.3 Partially meshed multiple devices

5.3.1 Objective

   To determine the throughput, frame loss and forwarding rates of two
   switching devices equipped with multiple ports and one high speed
   backbone uplink (Gigabit Ethernet, ATM, SONET).

5.3.2 Setup Parameters

   When offering bursty partially meshed traffic, the following
   parameters MUST be defined.  Each variable is configured with the
   following considerations.

      Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
      1280 and 1518 bytes, per RFC 2544 section 9 [3].  The four CRC
      bytes are included in the frame size specified.

      Interframe Gap (IFG) - The IFG between frames inside a burst MUST
      be at the minimum specified by the standard (9.6 us for 10Mbps
      Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1 Gbps
      Ethernet) of the medium being tested.

      Duplex mode - Half duplex or full duplex.

      ILoad - Intended Load per port is expressed in a percentage of the
      medium's maximum theoretical load, regardless of traffic
      orientation or duplex mode.  Certain test configurations will
      theoretically over-subscribe the DUT/SUT.

      In half duplex, an ILoad over 50% will over-subscribe the DUT/SUT.

      Burst Size - The burst size defines the number of frames sent
      back-to-back at the minimum legal IFG [4] before pausing
      transmission to receive frames.  Burst sizes SHOULD vary between 1
      and 930 frames.  A burst size of 1 will simulate constant load
      [1].

      Addresses per port - Represents the number of addresses which are
      being tested for each port.  Number of addresses SHOULD be a
      binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
      Recommended value is 1.

      Trial Duration - The recommended Trial Duration is 30 seconds.
      Trial duration SHOULD be adjustable between 1 and 300 seconds.






Mandeville & Perser          Informational                     [Page 10]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


      Local Traffic - A Boolean value of ON or OFF.  The frame sequence
      algorithm MAY be altered to remove local traffic.  With local
      traffic ON, the algorithm is exactly the same as a fully meshed
      throughput.  With local traffic OFF, the port sends frames to all
      other ports on the other side of the backbone uplink in a round
      robin type fashion.

5.3.3 Procedure

   All ports on the tester MUST transmit test frames either in a Frame
   Based or Time Based mode (Appendix B).  All ports SHOULD start
   transmitting their frames within 1% of the trial duration.  For a
   trial duration of 30 seconds, all ports SHOULD have started
   transmitting frames with 300 milliseconds of each other.

   Each port in the test MUST send test frames to all other ports in a
   round robin type fashion as defined in section 5.1.3.  Local traffic
   MAY be removed from the round robin list in order to send the entire
   load across the backbone uplink.

   For tests using multiple addresses per port, the actual port
   destinations are the same as described above and the actual
   source/destination address pairs SHOULD be chosen randomly to
   exercise the DUT/SUT's ability to perform address lookups.

   For every address, the testing device MUST send learning frames to
   allow the DUT/SUT to update its address tables properly.

   To measure the DUT/SUT's ability to switch traffic while performing
   many different address lookups, the number of addresses per port MAY
   be increased in a series of tests.

5.3.4 Measurements

   Each receiving port MUST categorize, then count the frames into one
   of two groups:

      1.) Received frames MUST have the correct destination MAC address
          and SHOULD match a signature field.

      2.) Flood count [2].

   Any frame originating from the DUT/SUT MUST not be counted as a
   received frame.  Frames originating from the DUT/SUT MAY be counted
   as flooded frames or not counted at all.






Mandeville & Perser          Informational                     [Page 11]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   Frame loss rate of the DUT/SUT SHOULD be reported as defined in
   section 26.3 [3] with the following notes: Frame loss rate SHOULD be
   measured at the end of the trial duration.  The term "rate", for this
   measurement only, does not imply the units in the fashion of "per
   second."

5.3.4.1 Throughput

   Throughput measurement is defined in section 26.1 [3].  A search
   algorithm is employed to find the maximum Oload [2] with a zero Frame
   loss rate [1].  The algorithm MUST adjust Iload to find the
   throughput.

5.3.4.2 Forwarding rate

   Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
   of test frames per second that the device is observed to successfully
   forward to the correct destination interface in response to a
   specified Oload.  The Oload MUST also be cited.

   Forwarding rate at maximum offered load (FRMOL) MUST be reported as
   the number of test frames per second that a device can successfully
   transmit to the correct destination interface in response to the MOL
   as defined in section 3.6 [2]. The MOL MUST also be cited.

   Maximum forwarding rate (MFR) MUST be reported as the highest
   forwarding rate of a DUT/SUT taken from an iterative set of
   forwarding rate measurements.  The iterative set of forwarding rate
   measurements are made by adjusting Iload.  The Oload applied to the
   device MUST also be cited.

5.3.5 Reporting format

   The results for these tests SHOULD be reported in the form of a
   graph.  The x coordinate SHOULD be the frame size, the y coordinate
   SHOULD be the test results.  There SHOULD be at least two lines on
   the graph, one plotting the theoretical and one plotting the test
   results.

   To measure the DUT/SUT's ability to switch traffic while performing
   many different address lookups, the number of addresses per port MAY
   be increased in a series of tests.









Mandeville & Perser          Informational                     [Page 12]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.4 Partially meshed unidirectional traffic

5.4.1 Objective

   To determine the throughput of the DUT/SUT when presented multiple
   streams of unidirectional traffic with half of the ports on the
   DUT/SUT are transmitting frames destined to the other half of the
   ports.

5.4.2 Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
      1280 and 1518 bytes, per RFC 2544 section 9 [3].  The four CRC
      bytes are included in the frame size specified.

      Interframe Gap (IFG) - The IFG between frames inside a burst MUST
      be at the minimum specified by the standard (9.6 us for 10Mbps
      Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1 Gbps
      Ethernet) of the medium being tested.

      Duplex mode - Half duplex or full duplex.

      ILoad - Intended Load per port is expressed in a percentage of the
      medium's maximum theoretical load, regardless of traffic
      orientation or duplex mode.  Certain test configurations will
      theoretically over-subscribe the DUT/SUT.

      ILoad will not over-subscribe the DUT/SUT in this test.

      Burst Size - The burst size defines the number of frames sent
      back-to-back at the minimum legal IFG [4] before pausing
      transmission to receive frames.  Burst sizes SHOULD vary between 1
      and 930 frames.  A burst size of 1 will simulate constant load
      [1].

      Addresses per port - Represents the number of addresses which are
      being tested for each port.  Number of addresses SHOULD be a
      binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
      Recommended value is 1.

      Trial Duration - The recommended Trial Duration is 30 seconds.
      Trial duration SHOULD be adjustable between 1 and 300 seconds.






Mandeville & Perser          Informational                     [Page 13]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.4.3 Procedure

      Ports do not send and receive test frames simultaneously.  As a
      consequence, there should be no collisions unless the DUT is
      misforwarding frames, generating flooded or Spanning-Tree frames
      or is enabling some flow control mechanism.  Ports used for this
      test are either transmitting or receiving, but not both. Those
      ports which are transmitting send test frames destined to
      addresses corresponding to each of the ports receiving.  This
      creates a unidirectional mesh of traffic.

      All ports on the tester MUST transmit test frames either in a
      Frame Based or Time Based mode (Appendix B).  All ports SHOULD
      start transmitting their frames within 1% of the trial duration.
      For a trial duration of 30 seconds, all ports SHOULD have started
      transmitting frames with 300 milliseconds of each other.

      Each transmitting port in the test MUST send frames to all
      receiving ports in a round robin type fashion.  The sequence of
      addresses MUST NOT change when congestion control is applied.
      The following table shows how each port in a test MUST transmit
      test frames to all other ports in the test.  In this 8 port
      example, port 1 through 4 are transmitting and ports 5 through 8
      are receiving; each with 1 address per port:

      Source Port, then Destination Ports (in order of transmission)

      Port #1              5       6       7       8       5       6...
      Port #2              6       7       8       5       6       7...
      Port #3              7       8       5       6       7       8...
      Port #4              8       5       6       7       8       5...

      As shown in the table, there is an equal distribution of
      destination addresses for each transmit opportunity. This keeps
      the test balanced so that one destination port is not overloaded
      by the test algorithm and all receiving ports are equally and
      fully loaded throughout the test.  Not following this algorithm
      exactly will product inconsistent results.

      For tests using multiple addresses per port, the actual port
      destinations are the same as described above and the actual
      source/destination address pairs SHOULD be chosen randomly to
      exercise the DUT/SUT's ability to perform address lookups.

      For every address, the testing device MUST send learning frames to
      allow the DUT/SUT to load its address tables properly.  The
      address table's aging time SHOULD be set sufficiently longer than




Mandeville & Perser          Informational                     [Page 14]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


      the learning time and trial duration time combined.  If the
      address table ages out during the test, the results will show a
      lower performing DUT/SUT.

      To measure the DUT/SUT's ability to switch traffic while
      performing many different address lookups, the number of addresses
      per port MAY be increased in a series of tests.

5.4.4 Measurements

      Each receiving port MUST categorize, then count the frames into
      one of two groups:

      1.) Received Frames: received frames MUST have the correct
          destination MAC address and SHOULD match a signature field.

      2.) Flood count [2].

   Any frame originating from the DUT/SUT MUST not be counted as a
   received frame.  Frames originating from the DUT/SUT MAY be counted
   as flooded frames or not counted at all.

   Frame loss rate of the DUT/SUT SHOULD be reported as defined in
   section 26.3 [3] with the following notes: Frame loss rate SHOULD be
   measured at the end of the trial duration.  The term "rate", for this
   measurement only, does not imply the units in the fashion of "per
   second."

5.4.4.1 Throughput

   Throughput measurement is defined in section 26.1 [3].  A search
   algorithm is employed to find the maximum Oload [2] with a zero Frame
   loss rate [1].  The algorithm MUST adjust Iload to find the
   throughput.

5.4.4.2 Forwarding rate

   Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
   of test frames per second that the device is observed to successfully
   forward to the correct destination interface in response to a
   specified Oload.  The Oload MUST also be cited.

   Forwarding rate at maximum offered load (FRMOL) MUST be reported as
   the number of test frames per second that a device can successfully
   transmit to the correct destination interface in response to the MOL
   as defined in section 3.6 [2]. The MOL MUST also be cited.





Mandeville & Perser          Informational                     [Page 15]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   Maximum forwarding rate (MFR) MUST be reported as the highest
   forwarding rate of a DUT/SUT taken from an iterative set of
   forwarding rate measurements.  The iterative set of forwarding rate
   measurements are made by adjusting Iload.  The Oload applied to the
   device MUST also be cited.

5.4.5 Reporting format

   The results for these tests SHOULD be reported in the form of a
   graph.  The x coordinate SHOULD be the frame size, the y coordinate
   SHOULD be the test results.  There SHOULD be at least two lines on
   the graph, one plotting the theoretical and one plotting the test
   results.

   To measure the DUT/SUT's ability to switch traffic while performing
   many different address lookups, the number of addresses per port MAY
   be increased in a series of tests.

5.5 Congestion Control

5.5.1 Objective

   To determine how a DUT handles congestion.  Does the device implement
   congestion control and does congestion on one port affect an
   uncongested port.  This procedure determines if Head of Line Blocking
   and/or Backpressure are present.

5.5.2 Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
      1280 and 1518 bytes, per RFC 2544 section 9 [3].  The four CRC
      bytes are included in the frame size specified.

      Interframe Gap (IFG) - The IFG between frames inside a burst MUST
      be at the minimum specified by the standard (9.6 us for 10Mbps
      Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1 Gbps
      Ethernet) of the medium being tested.

      Duplex mode - Half duplex or full duplex.

      Addresses per port - Represents the number of addresses which are
      being tested for each port.  Number of addresses SHOULD be a
      binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
      Recommended value is 1.




Mandeville & Perser          Informational                     [Page 16]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


      Trial Duration - The recommended Trial Duration is 30 seconds.
      Trial duration SHOULD be adjustable between 1 and 300 seconds.

5.5.3 Procedure

   This test MUST consist of a multiple of four ports with the same MOL.
   Four ports are REQUIRED and MAY be expanded to fully utilize the
   DUT/SUT in increments of four.  Each group of four will contain a
   test block with two of the ports as source transmitters and two of
   the ports as receivers. The diagram below depicts the flow of traffic
   between the switch ports:

        +----------+   50 % MOL                  +-------------+
        |          |  ------------------------>  |             |
        |          |   50 % MOL                  | uncongested |
        |          |  ---------                  |             |
        +----------+            \                +-------------+
                                 \
                                  \
                                   \
        +----------+                \            +-------------+
        |          |                 --------->  |             |
        |          |   100 % MOL                 | congested   |
        |          |  ------------------------>  |             |
        +----------+                             +-------------+

   Both source transmitters MUST transmit the exact number of test
   frames.  The first source MUST transmit test frames at the MOL with
   the destination address of the two receive ports in an alternating
   order.  The first test frame to the uncongested receive port, second
   test frame to the congested receive port, then repeat.  The second
   source transmitter MUST transmit test frames at the MOL only to the
   congested receive port.

   Both receive ports SHOULD distinguish between test frames originating
   from the source ports and frames originating from the DUT/SUT.  Only
   test frames from the source ports SHOULD be counted.

   The uncongested receive port should be receiving at a rate of half
   the MOL.  The number of test frames received on the uncongested port
   SHOULD be 50% of the test frames transmitted by the first source
   transmitter.  The congested receive port should be receiving at the
   MOL.  The number of test frames received on the congested port should
   be between 100% and 150% of the test frames transmitted by one source
   transmitter.






Mandeville & Perser          Informational                     [Page 17]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   Test frames destined to uncongested ports in a switch device should
   not be dropped due to other ports being congested, even if the source
   is sending to both the congested and uncongested ports.

5.5.4 Measurements

   Any frame received which does not have the correct destination
   address MUST not be counted as a received frame and SHOULD be counted
   as part of a flood count.

   Any frame originating from the DUT/SUT MUST not be counted as a
   received frame.  Frames originating from the DUT/SUT MAY be counted
   as flooded frames or not counted at all.

   Frame loss rate of the DUT/SUT's congested and uncongested ports MUST
   be reported as defined in section 26.3 [3] with the following notes:
   Frame loss rate SHOULD be measured at the end of the trial duration.
   The term "rate", for this measurement only, does not imply the units
   in the fashion of "per second."

   Offered Load to the DUT/SUT MUST be reported as the number of test
   frames per second that the DUT/SUT observed to accept.  This may be
   different that the MOL.

   Forwarding rate (FR) of the DUT/SUT's congested and uncongested ports
   MUST be reported as the number of test frames per second that the
   device is observed to successfully transmit to the correct
   destination interface in response to a specified offered load. The
   offered load MUST also be cited.

5.5.5 Reporting format

   This test MUST report the frame lost rate at the uncongested port,
   the forwarding rate (at 50% offered load) at the uncongested port,
   and the frame lost rate at the congested port.  This test MAY report
   the frame counts transmitted and frame counts received by the
   DUT/SUT.

5.5.5.1 HOLB

   If there is frame loss at the uncongested port, "Head of Line"
   blocking is present.  The DUT cannot forward the amount of traffic to
   the congested port and as a result it is also losing frames destined
   to the uncongested port.







Mandeville & Perser          Informational                     [Page 18]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.5.5.2 Back Pressure

   If there is no frame loss on the congested port, then backpressure is
   present.  It should be noted that this test expects the overall load
   to the congested port to be greater than 100%. Therefore if the load
   is greater than 100% and no frame loss is detected, then the DUT must
   be implementing a flow control mechanism.  The type of flow control
   mechanism used is beyond the scope of this memo.

   It should be noted that some DUTs may not be able to handle the 100%
   load presented at the input port. In this case, there may be frame
   loss reported at the uncongested port which is due to the load at the
   input port rather than the congested port's load.

   If the uncongested frame loss is reported as zero, but the maximum
   forwarding rate is less than 7440 (for 10Mbps Ethernet), then this
   may be an indication of congestion control being enforced by the DUT.
   In this case, the congestion control is affecting the throughput of
   the uncongested port.

   If no congestion control is detected, the expected percentage frame
   loss for the congested port is 33% at 150% overload.  It is receiving
   100% load from 1 port, and 50% from another, and can only get 100%
   possible throughput, therefore having a frame loss rate of 33%
   (150%-50%/150%).

5.6 Forward Pressure and Maximum Forwarding Rate

5.6.1 Objective

   The Forward Pressure test overloads a DUT/SUT port and measures the
   output for forward pressure [2].  If the DUT/SUT transmits frames
   with an interframe gap less than 96 bits (section 4.2.3.2.2 [4]),
   then forward pressure is detected.

   The objective of the Maximum Forwarding Rate test is to measure the
   peak value of the Forwarding Rate when the Offered Load is varied
   between the throughput [1] and the Maximum Offered Load [2].

5.6.2 Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
      1280 and 1518 bytes, per RFC 2544 section 9 [3].  The four CRC
      bytes are included in the frame size specified.




Mandeville & Perser          Informational                     [Page 19]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


      Duplex mode - Half duplex or full duplex.

      Trial Duration - The recommended Trial Duration is 30 seconds.
      Trial duration SHOULD be adjustable between 1 and 300 seconds.

      Step Size - The minimum incremental resolution that the Iload will
      be incremented in frames per second.  The smaller the step size,
      the more accurate the measurement and the more iterations
      required.  As the Iload approaches the MOL, the minimum step size
      will increase because of gap resolution on the testing device.

5.6.3 Procedure

5.6.3.1 Maximum forwarding rate

   If the Throughput [1] and the MOL [2] are the same, then MFR [2] is
   equal to the MOL [2].

   This test MUST at a minimum be performed in a two-port configuration
   as described below.  Learning frames MUST be sent to allow the
   DUT/SUT to update its address tables properly.

   Test frames are transmitted to the first port (port 1) of the DUT/SUT
   at the Iload.  The FR [2] on the second port (port 2) of the DUT/SUT
   is measured.  The Iload is incremented for each Step Size to find the
   MFR.  The algorithm for the test is as follows:

    CONSTANT
      MOL = ... frames/sec; {Maximum Offered Load}
    VARIABLE
      MFR   := 0 frames/sec; {Maximum Forwarding Rate}
      ILOAD := starting throughput in frames/sec; {offered load}
      STEP  := ... frames/sec; {Step Size}
    BEGIN
      ILOAD := ILOAD - STEP;
      DO
      BEGIN
        ILOAD := ILOAD + STEP
        IF (ILOAD > MOL) THEN
        BEGIN
          ILOAD := MOL
        END
        AddressLearning; {Port 2 broadcasts with its source address}
        Transmit(ILOAD); {Port 1 sends frames to Port 2 at Offered load}
        IF (Port 2 Forwarding Rate > MFR) THEN
        BEGIN
           MFR := Port 2 Forwarding Rate; {A higher value than before}
        END



Mandeville & Perser          Informational                     [Page 20]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


    END
    WHILE (ILOAD < MOL); {ILOAD has reached the MOL value}
    DONE

5.6.3.2 Minimum Interframe Gap

   The Minimum Interframe gap test SHOULD, at a minimum, be performed in
   a two-port configuration as described below.  Learning frames MUST be
   sent to allow the DUT/SUT to update its address tables properly.

   Test frames SHOULD be transmitted to the first port (port 1) of the
   DUT/SUT with an interframe gap of 88 bits.  This will apply forward
   pressure to the DUT/SUT and overload it at a rate of one byte per
   frame.  The test frames MUST be constructed with a source address of
   port 1 and a destination address of port 2.

   The FR on the second port (port 2) of the DUT/SUT is measured.  The
   measured Forwarding Rate should not exceed the medium's maximum
   theoretical utilization (MOL).

5.6.4 Measurements

   Port 2 MUST categorize, then count the frames into one of two groups:

      1.) Received Frames: received frames MUST have the correct
          destination MAC address and SHOULD match a signature field.

      2.) Flood count [2].

   Any frame originating from the DUT/SUT MUST not be counted as a
   received frame.  Frames originating from the DUT/SUT MAY be counted
   as flooded frames or not counted at all.

5.6.5 Reporting format

   MFR MUST be reported as the highest forwarding rate of a DUT/SUT
   taken from an iterative set of forwarding rate measurements. The
   Iload applied to the device MUST also be cited.

   Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
   of frames per second that the device is observed to successfully
   transmit to the correct destination interface in response to a
   specified Oload. The Iload MUST be cited and the Oload MAY be
   recorded.

   If the FR exceeds the MOL during the Minimum Interframe gap test,
   this MUST be highlighted with the expression "Forward Pressure
   detected".



Mandeville & Perser          Informational                     [Page 21]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


5.7 Address Caching Capacity

5.7.1 Objective

   To determine the address caching capacity of a LAN switching device
   as defined in RFC 2285, section 3.8.1 [2].

5.7.2 Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Age Time - The maximum time that a DUT/SUT will keep a learned
      address in its forwarding table.

      Addresses Learning Rate - The rate at which new addresses are
      offered to the DUT/SUT to be learned.  The rate at which address
      learning frames are offered may have to be adjusted to be as low
      as 50 frames per second or even less, to guarantee successful
      learning.

      Initial Addresses - The initial number of addresses to start the
      test with.  The number MUST be between 1 and the maximum number
      supported by the implementation.

5.7.3 Procedure

   The aging time of the DUT/SUT MUST be known.  The aging time MUST be
   longer than the time necessary to produce frames at the specified
   rate.  If a low frame rate is used for the test, then it may be
   possible that sending a large amount of frames may actually take
   longer than the aging time.

   This test MUST at a minimum be performed in a three-port
   configuration described below.  The test MAY be expanded to fully
   utilized the DUT/SUT in increments of two or three ports.  An
   increment of two would include an additional Learning port and Test
   port.  An increment of three would include an additional Learning
   port, Test port, and Monitoring port.

   The Learning port (Lport) transmits learning frames to the DUT/SUT
   with varying source addresses and a fixed destination address
   corresponding to the address of the device connected to the Test port
   (Tport) of the DUT/SUT.  By receiving frames with varying source
   addresses, the DUT/SUT should learn these new addresses.  The source
   addresses MAY be in sequential order.





Mandeville & Perser          Informational                     [Page 22]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   The Test port (Tport) of the DUT/SUT acts as the receiving port for
   the learning frames.  Test frames will be transmitted back to the
   addresses learned on the Learning port.  The algorithm for this is
   explained below.

   The Monitoring port (Mport) on the DUT/SUT acts as a monitoring port
   to listen for flooded or mis-forwarded frames.  If the test spans
   multiple broadcast domains (VLANs), each broadcast domain REQUIRES a
   Monitoring port.

   It is highly recommended that SNMP, Spanning Tree, and any other
   frames originating from the DUT/SUT be disabled when running this
   test.  If such protocols cannot be turned off, the flood count MUST
   be modified only to count test frame originating from Lport and MUST
   NOT count frames originating from the DUT/SUT.

   The algorithm for the test is as follows:

   CONSTANT
      AGE = ...;  {value greater that DUT aging time}
      MAX = ...;  {maximum address support by implementation}
    VARIABLE
      LOW  := 0;    {Highest passed valve}
      HIGH := MAX;  {Lowest failed value}
      N    := ...;  {user specified initial starting point}
    BEGIN
      DO
        BEGIN
        PAUSE(AGE);   {Age out any learned addresses}
          AddressLearning(TPort); {broadcast a frame with its source
                                  Address and broadcast destination}
          AddressLearning(LPort); {N frames with varying source addresses
                                  to Test Port}
        Transmit(TPort); {N frames with varying destination addresses
                           corresponding to Learning Port}
        IF (MPort receive frame != 0) OR
           (LPort receive frames < TPort transmit) THEN
          BEGIN  {Address Table of DUT/SUT was full}
            HIGH := N;
          END
        ELSE
          BEGIN  {Address Table of DUT/SUT was NOT full}
            LOW := N;
          END
        N := LOW + (HIGH - LOW)/2;
      END WHILE (HIGH - LOW >= 2);
    END {Value of N equals number of addresses supported by DUT/SUT}




Mandeville & Perser          Informational                     [Page 23]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   Using a binary search approach, the test targets the exact number of
   addresses supported per port with consistent test iterations.  Due to
   the aging time of DUT/SUT address tables, each iteration may take
   some time during the waiting period for the addresses to clear.  If
   possible, configure the DUT/SUT for a low value for the aging time.

   Once the high and low values of N meet, then the threshold of address
   handling has been found.

5.7.4 Measurements

   Whether the offered addresses per port was successful forwarded
   without flooding.

5.7.5 Reporting format

   After the test is run, results for each iteration SHOULD be displayed
   in a table to include:

      The number of addresses used for each test iteration (varied).

      The intended load used for each test iteration (fixed).

      Number of test frames that were offered to Tport of the DUT/SUT.
      This SHOULD match the number of addresses used for the test
      iteration.  Test frames are the frames sent with varying
      destination addresses to confirm that the DUT/SUT has learned all
      of the addresses for each test iteration.

      The flood count on Tport during the test portion of each test.  If
      the number is non-zero, this is an indication of the DUT/SUT
      flooding a frame in which the destination address is not in the
      address table.

      The number of frames correctly forwarded to test Lport during the
      test portion of the test.  Received frames MUST have the correct
      destination MAC address and SHOULD match a signature field.  For a
      passing test iteration, this number should be equal to the number
      of frames transmitted by Tport.

      The flood count on Lport during the test portion of each test.  If
      the number is non-zero, this is an indication of the DUT/SUT
      flooding a frame in which the destination address is not in the
      address table.







Mandeville & Perser          Informational                     [Page 24]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


      The flood count on Mport.  If the value is not zero, then this
      indicates that for that test iteration, the DUT/SUT could not
      determine the proper destination port for that many frames.  In
      other words, the DUT/SUT flooded the frame to all ports since its
      address table was full.

5.8 Address Learning Rate

5.8.1 Objective

   To determine the rate of address learning of a LAN switching device.

5.8.2 Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Age Time - The maximum time that a DUT/SUT will keep a learned
      address in its forwarding table.

      Initial Addresses Learning Rate - The starting rate at which new
      addresses are offered to the DUT/SUT to be learned.

      Number of Addresses - The number of addresses that the DUT/SUT
      must learn.  The number MUST be between 1 and the maximum number
      supported by the implementation.  It is recommended no to exceed
      the address caching capacity found in section 5.9

5.8.3 Procedure

   The aging time of the DUT/SUT MUST be known.  The aging time MUST be
   longer than the time necessary to produce frames at the specified
   rate.  If a low frame rate is used for the test, then it may be
   possible that sending a large amount of frames may actually take
   longer than the aging time.

   This test MUST at a minimum be performed in a three-port
   configuration in section 5.9.3.  The test MAY be expanded to fully
   utilized the DUT/SUT in increments of two or three ports.  An
   increment of two would include an additional Learning port and Test
   port.  An increment of three would include an additional Learning
   port, Test port, and Monitoring port.

   An algorithm similar to the one used to determine address caching
   capacity can be used to determine the address learning rate.  This
   test iterates the rate at which address learning frames are offered





Mandeville & Perser          Informational                     [Page 25]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   by the test device connected to the DUT/SUT.  It is recommended to
   set the number of addresses offered to the DUT/SUT in this test to
   the maximum caching capacity.

   The address learning rate might be determined for different numbers
   of addresses but in each test run, the number MUST remain constant
   and SHOULD be equal to or less than the maximum address caching
   capacity.

5.8.4 Measurements

   Whether the offered addresses per port were successful forwarded
   without flooding at the offered learning rate.

5.8.5 Reporting format

   After the test is run, results for each iteration SHOULD be displayed
   in a table:

      The number of addresses used for each test iteration (fixed).

      The intended load used for each test iteration (varied).

      Number of test frames that were transmitted by Tport.  This SHOULD
      match the number of addresses used for the test iteration.  Test
      frames are the frames sent with varying destination addresses to
      confirm that the DUT/SUT has learned all of the addresses for each
      test iteration.

      The flood count on Tport during the test portion of each test.  If
      the number is non-zero, this is an indication of the DUT/SUT
      flooding a frame in which the destination address is not in the
      address table.

      The number of frames correctly forwarded to test Lport during the
      test portion of the test.  Received frames MUST have the correct
      destination MAC address and SHOULD match a signature field.  For a
      passing test iteration, this number should be equal to the number
      of frames transmitted by Tport.

      The flood count on Lport during the test portion of each test.  If
      the number is non-zero, this is an indication of the DUT/SUT
      flooding a frame in which the destination address is not in the
      address table.







Mandeville & Perser          Informational                     [Page 26]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


      The flood count on Mport.  If the value is not zero, then this
      indicates that for that test iteration, the DUT/SUT could not
      determine the proper destination port for that many frames.  In
      other words, the DUT/SUT flooded the frame to all ports since its
      address table was full.

5.9 Errored frames filtering

5.9.1 Objective

   The objective of the Errored frames filtering test is to determine
   the behavior of the DUT under error or abnormal frame conditions.
   The results of the test indicate if the DUT/SUT filters the errors,
   or simply propagates the errored frames along to the destination.

5.9.2 Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      ILoad - Intended Load per port is expressed in a percentage of the
      medium's maximum theoretical load possible.  The actual
      transmitted frame per second is dependent upon half duplex or full
      duplex operation.  The test SHOULD be run multiple times with a
      different load per port in each case.

      Trial Duration - The recommended Trial Duration is 30 seconds.
      Trial duration SHOULD be adjustable between 1 and 300 seconds.

5.9.3 Procedure

   Each of the illegal frames for Ethernet MUST be checked:

   Oversize - The DUT/SUT MAY filter frames larger than 1518 bytes from
   being propagated through the DUT/SUT section 4.2.4.2.1 [4].
   Oversized frames transmitted to the DUT/SUT should not be forwarded.
   DUT/SUT supporting tagged Frames MAY forward frames up to and
   including 1522 bytes long (section 4.2.4.2.1 [5]).

   Undersize - The DUT/SUT MUST filter frames less than 64 bytes from
   being propagated through the DUT/SUT (section 4.2.4.2.2 [4]).
   Undersized frames (or collision fragments) received by the DUT/SUT
   must not be forwarded.

   CRC Errors - The DUT/SUT MUST filter frames that fail the Frame Check
   Sequence Validation (section 4.2.4.1.2 [4]) from being propagated
   through the DUT/SUT.  Frames with an invalid CRC transmitted to the
   DUT/SUT should not be forwarded.



Mandeville & Perser          Informational                     [Page 27]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   Dribble Bit Errors - The DUT/SUT MUST correct and forward frames
   containing dribbling bits.  Frames transmitted to the DUT/SUT that do
   not end in an octet boundary but contain a valid frame check sequence
   MUST be accepted by the DUT/SUT (section 4.2.4.2.1 [4]) and forwarded
   to the correct receive port with the frame ending in an octet
   boundary (section 3.4 [4]).

   Alignment Errors - The DUT/SUT MUST filter frames that fail the Frame
   Check Sequence Validation AND do not end in an octet boundary.  This
   is a combination of a CRC error and a Dribble Bit error.  When both
   errors are occurring in the same frame, the DUT/SUT MUST determine
   the CRC error takes precedence and filters the frame (section
   4.2.4.1.2 [4]) from being propagated.

5.9.5 Reporting format

   For each of the error conditions in section 5.6.3, a "pass" or "fail"
   MUST be reported.  Actual frame counts MAY be reported for diagnostic
   purposes.

5.10 Broadcast frame Forwarding and Latency

5.10.1 Objective

   The objective of the Broadcast Frame Forwarding and Latency Test is
   to determine the throughput and latency of the DUT when forwarding
   broadcast traffic.  The ability to forward broadcast frames will
   depend upon a specific function built into the device for that
   purpose.  It is therefore necessary to determine the ability of
   DUT/SUT to handle broadcast frames, since there may be many different
   ways of implementing such a function.

5.10.2 Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
      1280 and 1518 bytes, per RFC 2544 section 9 [3].  The four CRC
      bytes are included in the frame size specified.

      Duplex mode - Half duplex or full duplex.

      ILoad - Intended Load per port is expressed in a percentage of the
      medium's maximum theoretical load, regardless of traffic
      orientation or duplex mode.  Certain test configurations will
      theoretically over-subscribe the DUT/SUT.




Mandeville & Perser          Informational                     [Page 28]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


      ILoad will not over-subscribe the DUT/SUT in this test.

      Trial Duration - The recommended Trial Duration is 30 seconds.
      Trial duration SHOULD be adjustable between 1 and 300 seconds.

5.10.3 Procedure

   For this test, there are two parts to be run.

   Broadcast Frame Throughput - This portion of the test uses a single
   source test port to transmit test frames with a broadcast address
   using the frame specified in RFC 2544 [3].  Selected receive ports
   then measure the forwarding rate and Frame loss rate.

   Broadcast Frame Latency - This test uses the same setup as the
   Broadcast Frame throughput, but instead of a large stream of test
   frames being sent, only one test frame is sent and the latency to
   each of the receive ports are measured in seconds.

5.10.4 Measurements

   Frame loss rate of the DUT/SUT SHOULD be reported as defined in
   section 26.3 [3] with the following notes: Frame loss rate SHOULD be
   measured at the end of the trial duration.  The term "rate", for this
   measurement only, does not imply the units in the fashion of "per
   second."

   Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
   of test frames per second that the device is observed to successfully
   forward to the correct destination interface in response to a
   specified Oload.  The Oload MUST also be cited.

5.10.5 Reporting format

   The results for these tests SHOULD be reported in the form of a
   graph.  The x coordinate SHOULD be the frame size, the y coordinate
   SHOULD be the test results.  There SHOULD be at least two lines on
   the graph, one plotting the theoretical and one plotting the test
   results.

   To measure the DUT/SUT's ability to switch traffic while performing
   many different address lookups, the number of addresses per port MAY
   be increased in a series of tests.








Mandeville & Perser          Informational                     [Page 29]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


6. Security Considerations

   As this document is solely for the purpose of providing metric
   methodology and describes neither a protocol nor a protocol's
   implementation, there are no security considerations associated with
   this document.

7.  References

   [1]   Bradner, S., Editor, "Benchmarking Terminology for Network
         Interconnection Devices", RFC 1242, July 1991.

   [2]   Mandeville, R., "Benchmarking Terminology for LAN Switching
         Devices", RFC 2285, February 1998.

   [3]   Bradner, S. and J. McQuaid, "Benchmarking Methodology for
         Network Interconnect Devices", RFC 2544, March 1999.

   [4]   ANSI/IEEE, "CSMA/CD Access Method and Physical Layer
         Specifications," ISO/IEC 8802-3, ISBN 0-7381-0330-6, 1998.

   [5]   IEEE Draft, "Frame Extensions for Virtual Bridged Local Area
         Networks (VLAN) Tagging on 802.3 Networks", 802.3ac/D3.1, July
         1998.

8. Authors' Addresses

   Robert Mandeville
   CQOS Inc.
   21 Technology
   Irvine, CA 92618
   USA

   Phone: +1 (949) 400-4444
   EMail: bob@cqos.com


   Jerry Perser
   Spirent Communications
   26750 Agoura Road
   Calabasas, CA 91302
   USA

   Phone: + 1 818 676 2300
   EMail: jerry_perser@netcomsystems.com






Mandeville & Perser          Informational                     [Page 30]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


Appendix A:  Formulas

A.1 Calculating the InterBurst Gap

   IBG is defined in RFC 2285 [2] as the interval between two bursts.
   To achieve a desired load, the following Input Parameter need to be
   defined:

     LENGTH - Frame size in bytes including the CRC.

     LOAD   - The intended load in percent.  Range is 0 to 100.

     BURST  - The number of frames in the burst (integer value).

     SPEED  - media's speed in bits/sec
                 Ethernet is 10,000,000 bits/sec
                 Fast Ethernet is 100,000,000 bits/sec
                 Gigabit Ethernet is 1,000,000,000 bits/sec

     IFG    - A constant 96 bits for the minimum interframe gap.

   The IBG (in seconds) can be calculated:


          [(100/LOAD - 1) * BURST * (IFG + 64 + 8*LENGTH)] + IFG
   IBG = -----------------------------------------------------------
                                  SPEED

A.2 Calculating the Number of Bursts for the Trial Duration

   The number of bursts for the trial duration is rounded up to the
   nearest integer number.  The follow Input Parameter need to be
   defined:

     LENGTH - Frame size in bytes including the CRC.

     BURST  - The number of frames in the burst (integer value).

     SPEED  - media's speed in bits/sec
                 Ethernet is 10,000,000 bits/sec
                 Fast Ethernet is 100,000,000 bits/sec
                 Gigabit Ethernet is 1,000,000,000 bits/sec

     IFG    - A constant 96 bits for the minimum interframe gap.

     IBG    - Found in the above formula

     DURATION - Trial duration in seconds.



Mandeville & Perser          Informational                     [Page 31]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   An intermediate number of the Burst duration needs to be calculated
   first:

    TXTIME  =  -----------------------------------------
                               SPEED

   Number of Burst for the Trial Duration (rounded up):

                     DURATION
    #OFBURSTS =   --------------
                  (TXTIME + IBG)

   Example:

     LENGTH   = 64  bytes per frame
     LOAD     = 100 % offered load
     BURST    = 24  frames per burst
     SPEED    = 10  Mbits/sec (Ethernet)
     DURATION = 10  seconds test


    IBG       = 1612.8 uS
      TXTIME    = 1603.2 uS
    #OFBURSTS = 3110

Appendix B: Generating Offered Load

   In testing, the traffic generator is configured with the Iload
   (Intended Load) and measures the Oload (Offered Load).  If the
   DUT/SUT applies congestion control, then the Iload and the Oload are
   not the same value. The question arises, how to generate the Oload?
   This appendix will describe two different methods.

   The unit of measurement for Oload is bits per second.  The two
   methods described here will hold one unit constant and let the
   DUT/SUT vary the other unit.  The traffic generator SHOULD specify
   which method it uses.

B.1 Frame Based Load

   Frame Based Load holds the number of bits constant.  The Trial
   Duration will vary based upon congestion control.  Advantage is
   implementation is a simple state machine (or loop).  The disadvantage
   is that Oload needs to be measured independently.







Mandeville & Perser          Informational                     [Page 32]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   All ports on the traffic generator MUST transmit the exact number of
   test frames.  The exact number of test frames is found by multiplying
   the Iload of the port by the Trial Duration.  All ports MAY NOT
   transmit the same number of frames if their Iload is not the same.
   An example would be the Partially meshed many-to-one test.

   All ports SHOULD start transmitting their frames within 1% of the
   trial duration.  For a trial duration of 30 seconds, all ports SHOULD
   have started transmitting frames within 300 milliseconds of each
   other.

   The reported Oload SHOULD be the average during the Trial Duration.
   If the traffic generator continues to transmit after the Trial
   Duration due to congestion control, Oload MAY be averaged over the
   entire transmit time.  Oload for the DUT/SUT MUST be the aggregate of
   all the Oloads per port.  Oload per port MAY be reported.

B.2 Time Based Load

   Time based load holds the Trial Duration constant, while allowing the
   number of octets transmitted to vary.  Advantages are an accurate
   Trial Duration and integrated Oload measurement.  Disadvantage is
   that the starting and stopping of the traffic generator MUST be more
   accurate.

   All ports on the traffic generator are configured to transmit the
   Iload for a finite amount of time.  Each port MUST count the number
   of octets successfully transmitted.

   The start and stop is initiated at a layer defined by the test
   parameters.  The layer can be the MAC layer, IP layer, or some other
   point in the protocol stack.  The traffic generator MUST complete its
   layer specific transmit process when the stop time is reached (i.e.
   no fragments, finish the frame).

   All ports MUST start transmitting their frames within 1% of the trial
   duration.  For a trial duration of 30 seconds, all ports SHOULD have
   started transmitting frames within 300 milliseconds of each other.

   All ports SHOULD stop transmitting frames after the specified trail
   duration within 0.01% of the trial duration.  Each port's stop time
   MUST be reference to its start time.  This trial duration error
   controls the accuracy of the Oload measurement and SHOULD be reported
   with the Oload measurement.

   Each port is allowed an offset error of 0.1% and a trial duration
   error of 0.01%.




Mandeville & Perser          Informational                     [Page 33]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


   Oload is found by taking the number of octets successfully
   transmitted and dividing by the trial duration.  Oload for the
   DUT/SUT MUST be the aggregate of all the Oloads per port.  Oload per
   port MAY be reported for diagnostic purposes.















































Mandeville & Perser          Informational                     [Page 34]

RFC 2889          LAN Switch Benchmarking Methodology        August 2000


Full Copyright Statement

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















Mandeville & Perser          Informational                     [Page 35]