summaryrefslogtreecommitdiff
path: root/doc/rfc/rfc4675.txt
blob: 41ca11def83993d4c9bb5ec24bd16579b54f90ac (plain) (blame)
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
Network Working Group                                         P. Congdon
Request for Comments: 4675                                    M. Sanchez
Category: Standards Track                        Hewlett-Packard Company
                                                                B. Aboba
                                                   Microsoft Corporation
                                                          September 2006


         RADIUS Attributes for Virtual LAN and Priority Support

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   This document proposes additional Remote Authentication Dial-In User
   Service (RADIUS) attributes for dynamic Virtual LAN assignment and
   prioritization, for use in provisioning of access to IEEE 802 local
   area networks.  These attributes are usable within either RADIUS or
   Diameter.






















Congdon, et al.             Standards Track                     [Page 1]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


Table of Contents

   1. Introduction ....................................................3
      1.1. Terminology ................................................3
      1.2. Requirements Language ......................................3
      1.3. Attribute Interpretation ...................................3
   2. Attributes ......................................................4
      2.1. Egress-VLANID ..............................................4
      2.2. Ingress-Filters ............................................6
      2.3. Egress-VLAN-Name ...........................................7
      2.4. User-Priority-Table ........................................8
   3. Table of Attributes ............................................10
   4. Diameter Considerations ........................................10
   5. IANA Considerations ............................................11
   6. Security Considerations ........................................11
   7. References .....................................................12
      7.1. Normative References ......................................12
      7.2. Informative References ....................................13
   8. Acknowledgements ...............................................13
































Congdon, et al.             Standards Track                     [Page 2]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


1.  Introduction

   This document describes Virtual LAN (VLAN) and re-prioritization
   attributes that may prove useful for provisioning of access to IEEE
   802 local area networks [IEEE-802] with the Remote Authentication
   Dial-In User Service (RADIUS) or Diameter.

   While [RFC3580] enables support for VLAN assignment based on the
   tunnel attributes defined in [RFC2868], it does not provide support
   for a more complete set of VLAN functionality as defined by
   [IEEE-802.1Q].  The attributes defined in this document provide
   support within RADIUS and Diameter analogous to the management
   variables supported in [IEEE-802.1Q] and MIB objects defined in
   [RFC4363].  In addition, this document enables support for a wider
   range of [IEEE-802.1X] configurations.

1.1.  Terminology

   This document uses the following terms:

   Network Access Server (NAS)
        A device that provides an access service for a user to a
        network.  Also known as a RADIUS client.

   RADIUS server
        A RADIUS authentication server is an entity that provides an
        authentication service to a NAS.

   RADIUS proxy
        A RADIUS proxy acts as an authentication server to the NAS, and
        a RADIUS client to the RADIUS server.

1.2.  Requirements Language

   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 [RFC2119].

1.3.  Attribute Interpretation

   The attributes described in this document apply to a single instance
   of a NAS port, or more specifically an IEEE 802.1Q bridge port.
   [IEEE-802.1Q], [IEEE-802.1D], and [IEEE-802.1X] do not recognize
   finer management granularity than "per port".  In some cases, such as
   with IEEE 802.11 wireless LANs, the concept of a "virtual port" is
   used in place of the physical port.  Such virtual ports are typically
   based on security associations and scoped by station, or Media Access
   Control (MAC) address.



Congdon, et al.             Standards Track                     [Page 3]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


   The attributes defined in this document are applied on a per-user
   basis and it is expected that there is a single user per port;
   however, in some cases that port may be a "virtual port".  If a NAS
   implementation conforming to this document supports "virtual ports",
   it may be possible to provision those "virtual ports" with unique
   values of the attributes described in this document, allowing
   multiple users sharing the same physical port to each have a unique
   set of authorization parameters.

   If a NAS conforming to this specification receives an Access-Accept
   packet containing an attribute defined in this document that it
   cannot apply, it MUST act as though it had received an Access-Reject.
   [RFC3576] requires that a NAS receiving a Change of Authorization
   Request (CoA-Request) reply with a CoA-NAK if the Request contains an
   unsupported attribute.  It is recommended that an Error-Cause
   attribute with the value set to "Unsupported Attribute" (401) be
   included in the CoA-NAK.  As noted in [RFC3576], authorization
   changes are atomic so that this situation does not result in session
   termination and the preexisting configuration remains unchanged.  As
   a result, no accounting packets should be generated.

2.  Attributes

2.1.  Egress-VLANID

   Description

      The Egress-VLANID attribute represents an allowed IEEE 802 Egress
      VLANID for this port, indicating if the VLANID is allowed for
      tagged or untagged frames as well as the VLANID.

      As defined in [RFC3580], the VLAN assigned via tunnel attributes
      applies both to the ingress VLANID for untagged packets (known as
      the PVID) and the egress VLANID for untagged packets.  In
      contrast, the Egress-VLANID attribute configures only the egress
      VLANID for either tagged or untagged packets.  The Egress-VLANID
      attribute MAY be included in the same RADIUS packet as [RFC3580]
      tunnel attributes; however, the Egress-VLANID attribute is not
      necessary if it is being used to configure the same untagged
      VLANID included in tunnel attributes.  To configure an untagged
      VLAN for both ingress and egress, the tunnel attributes of
      [RFC3580] MUST be used.

      Multiple Egress-VLANID attributes MAY be included in Access-
      Request, Access-Accept, CoA-Request, or Accounting-Request
      packets; this attribute MUST NOT be sent within an Access-
      Challenge, Access-Reject, Disconnect-Request, Disconnect-ACK,




Congdon, et al.             Standards Track                     [Page 4]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


      Disconnect-NAK, CoA-ACK, or CoA-NAK.  Each attribute adds the
      specified VLAN to the list of allowed egress VLANs for the port.

      The Egress-VLANID attribute is shown below.  The fields are
      transmitted from left to right:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |    Length     |            Value
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      56

   Length

      6

   Value

      The Value field is four octets.  The format is described below:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Tag Indic.   |        Pad            |       VLANID          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      The Tag Indication field is one octet in length and indicates
      whether the frames on the VLAN are tagged (0x31) or untagged
      (0x32).  The Pad field is 12 bits in length and MUST be 0 (zero).
      The VLANID is 12 bits in length and contains the [IEEE-802.1Q]
      VLAN VID value.














Congdon, et al.             Standards Track                     [Page 5]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


2.2.  Ingress-Filters

   Description

      The Ingress-Filters attribute corresponds to the Ingress Filter
      per-port variable defined in [IEEE-802.1Q] clause 8.4.5.  When the
      attribute has the value "Enabled", the set of VLANs that are
      allowed to ingress a port must match the set of VLANs that are
      allowed to egress a port.  Only a single Ingress-Filters attribute
      MAY be sent within an Access-Request, Access-Accept, CoA-Request,
      or Accounting-Request packet; this attribute MUST NOT be sent
      within an Access-Challenge, Access-Reject, Disconnect-Request,
      Disconnect-ACK, Disconnect-NAK, CoA-ACK, or CoA-NAK.

      The Ingress-Filters attribute is shown below.  The fields are
      transmitted from left to right:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |    Length     |         Value
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Value (cont)            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      57

   Length

      6

   Value

      The Value field is four octets.  Supported values include:

      1 - Enabled
      2 - Disabled












Congdon, et al.             Standards Track                     [Page 6]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


2.3.  Egress-VLAN-Name

   Description

      Clause 12.10.2.1.3 (a) in [IEEE-802.1Q] describes the
      administratively assigned VLAN Name associated with a VLAN-ID
      defined within an IEEE 802.1Q bridge.  The Egress-VLAN-Name
      attribute represents an allowed VLAN for this port.  It is similar
      to the Egress-VLANID attribute, except that the VLAN-ID itself is
      not specified or known; rather, the VLAN name is used to identify
      the VLAN within the system.

      The tunnel attributes described in [RFC3580] and the Egress-VLAN-
      Name attribute both can be used to configure the egress VLAN for
      untagged packets.  These attributes can be used concurrently and
      MAY appear in the same RADIUS packet.  When they do appear
      concurrently, the list of allowed VLANs is the concatenation of
      the Egress-VLAN-Name and the Tunnel-Private-Group-ID (81)
      attributes.  The Egress-VLAN-Name attribute does not alter the
      ingress VLAN for untagged traffic on a port (also known as the
      PVID).  The tunnel attributes from [RFC3580] should be relied upon
      instead to set the PVID.

      The Egress-VLAN-Name attribute contains two parts; the first part
      indicates if frames on the VLAN for this port are to be
      represented in tagged or untagged format, the second part is the
      VLAN name.

      Multiple Egress-VLAN-Name attributes MAY be included within an
      Access-Request, Access-Accept, CoA-Request, or Accounting-Request
      packet; this attribute MUST NOT be sent within an Access-
      Challenge, Access-Reject, Disconnect-Request, Disconnect-ACK,
      Disconnect-NAK, CoA-ACK, or CoA-NAK.  Each attribute adds the
      named VLAN to the list of allowed egress VLANs for the port.  The
      Egress-VLAN-Name attribute is shown below.  The fields are
      transmitted from left to right:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |    Length     |   Tag Indic.  |   String...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      58





Congdon, et al.             Standards Track                     [Page 7]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


   Length

      >=4

   Tag Indication

      The Tag Indication field is one octet in length and indicates
      whether the frames on the VLAN are tagged (0x31, ASCII '1') or
      untagged (0x32, ASCII '2').  These values were chosen so as to
      make them easier for users to enter.

   String

      The String field is at least one octet in length and contains the
      VLAN Name as defined in [IEEE-802.1Q] clause 12.10.2.1.3 (a).
      [RFC3629] UTF-8 encoded 10646 characters are RECOMMENDED, but a
      robust implementation SHOULD support the field as undistinguished
      octets.

2.4.  User-Priority-Table

   Description

      [IEEE-802.1D] clause 7.5.1 discusses how to regenerate (or re-map)
      user priority on frames received at a port.  This per-port
      configuration enables a bridge to cause the priority of received
      traffic at a port to be mapped to a particular priority.
      [IEEE-802.1D] clause 6.3.9 describes the use of remapping:

         The ability to signal user priority in IEEE 802 LANs allows
         user priority to be carried with end-to-end significance across
         a Bridged Local Area Network.  This, coupled with a consistent
         approach to the mapping of user priority to traffic classes and
         of user priority to access_priority, allows consistent use of
         priority information, according to the capabilities of the
         Bridges and MACs in the transmission path...

         Under normal circumstances, user priority is not modified in
         transit through the relay function of a Bridge; however,
         network management can control how user priority is propagated.
         Table 7-1 provides the ability to map incoming user priority
         values on a per-Port basis.  By default, the regenerated user
         priority is identical to the incoming user priority.

      This attribute represents the IEEE 802 prioritization that will be
      applied to frames arriving at this port.  There are eight possible
      user priorities, according to the [IEEE-802] standard.
      [IEEE-802.1D] clause 14.6.2.3.3 specifies the regeneration table



Congdon, et al.             Standards Track                     [Page 8]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


      as 8 values, each an integer in the range 0-7.  The management
      variables are described in clause 14.6.2.2.

      A single User-Priority-Table attribute MAY be included in an
      Access-Accept or CoA-Request packet; this attribute MUST NOT be
      sent within an Access-Request, Access-Challenge, Access-Reject,
      Disconnect-Request, Disconnect-ACK, Disconnect-NAK, CoA-ACK, CoA-
      NAK or Accounting-Request.  Since the regeneration table is only
      maintained by a bridge conforming to [IEEE-802.1D], this attribute
      should only be sent to a RADIUS client supporting that
      specification.

      The User-Priority-Table attribute is shown below.  The fields are
      transmitted from left to right:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |  Length       |          String
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                    String
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    String            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type

      59

   Length

      10

   String

      The String field is 8 octets in length and includes a table that
      maps the incoming priority (if it is set -- the default is 0) into
      one of eight regenerated priorities.  The first octet maps to
      incoming priority 0, the second octet to incoming priority 1, etc.
      The values in each octet represent the regenerated priority of the
      frame.

      It is thus possible to either remap incoming priorities to more
      appropriate values; to honor the incoming priorities; or to
      override any incoming priorities, forcing them to all map to a
      single chosen priority.





Congdon, et al.             Standards Track                     [Page 9]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


      The [IEEE-802.1D] specification, Annex G, provides a useful
      description of traffic type - traffic class mappings.

3.  Table of Attributes

   The following table provides a guide to which attributes may be found
   in which kinds of packets, and in what quantity.

   Access- Access- Access- Access-   CoA-  Acct-
   Request Accept  Reject  Challenge Req   Req   #   Attribute
    0+      0+      0       0        0+    0+   56   Egress-VLANID
    0-1     0-1     0       0        0-1   0-1  57   Ingress-Filters
    0+      0+      0       0        0+    0+   58   Egress-VLAN-Name
    0       0-1     0       0        0-1   0    59   User-Priority-Table

   The following table defines the meaning of the above table entries.

     0     This attribute MUST NOT be present in the packet.
     0+    Zero or more instances of this attribute MAY be
           present in the packet.
     0-1   Zero or one instance of this attribute MAY be
           present in the packet.

4.  Diameter Considerations

   When used in Diameter, the attributes defined in this specification
   can be used as Diameter attribute-value pair (AVPs) from the Code
   space 1-255 (RADIUS attribute compatibility space).  No additional
   Diameter Code values are therefore allocated.  The data types and
   flag rules for the attributes are as follows:

                                  +---------------------+
                                  |    AVP Flag rules   |
                                  |----+-----+----+-----|----+
                                  |    |     |SHLD| MUST|    |
   Attribute Name      Value Type |MUST| MAY | NOT|  NOT|Encr|
   -------------------------------|----+-----+----+-----|----|
   Egress-VLANID       OctetString| M  |  P  |    |  V  | Y  |
   Ingress-Filters     Enumerated | M  |  P  |    |  V  | Y  |
   Egress-VLAN-Name    UTF8String | M  |  P  |    |  V  | Y  |
   User-Priority-Table OctetString| M  |  P  |    |  V  | Y  |
   -------------------------------|----+-----+----+-----|----|

   The attributes in this specification have no special translation
   requirements for Diameter to RADIUS or RADIUS to Diameter gateways;
   they are copied as is, except for changes relating to headers,
   alignment, and padding.  See also [RFC3588] Section 4.1 and [RFC4005]
   Section 9.



Congdon, et al.             Standards Track                    [Page 10]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


   What this specification says about the applicability of the
   attributes for RADIUS Access-Request packets applies in Diameter to
   AA-Request [RFC4005] or Diameter-EAP-Request [RFC4072].  What is said
   about Access-Challenge applies in Diameter to AA-Answer [RFC4005] or
   Diameter-EAP-Answer [RFC4072] with Result-Code AVP set to
   DIAMETER_MULTI_ROUND_AUTH.

   What is said about Access-Accept applies in Diameter to AA-Answer or
   Diameter-EAP-Answer messages that indicate success.  Similarly, what
   is said about RADIUS Access-Reject packets applies in Diameter to
   AA-Answer or Diameter-EAP-Answer messages that indicate failure.

   What is said about COA-Request applies in Diameter to Re-Auth-Request
   [RFC4005].

   What is said about Accounting-Request applies to Diameter
   Accounting-Request [RFC4005] as well.

5.  IANA Considerations

   This specification does not create any new registries.

   This document uses the RADIUS [RFC2865] namespace; see
   <http://www.iana.org/assignments/radius-types>.  Allocation of four
   updates for the section "RADIUS Attribute Types" has been made by the
   IANA.  The RADIUS attributes are:

   56 - Egress-VLANID
   57 - Ingress-Filters
   58 - Egress-VLAN-Name
   59 - User-Priority-Table

6.  Security Considerations

   This specification describes the use of RADIUS and Diameter for
   purposes of authentication, authorization, and accounting in IEEE 802
   local area networks.  RADIUS threats and security issues for this
   application are described in [RFC3579] and [RFC3580]; security issues
   encountered in roaming are described in [RFC2607].  For Diameter, the
   security issues relating to this application are described in
   [RFC4005] and [RFC4072].

   This document specifies new attributes that can be included in
   existing RADIUS packets, which are protected as described in
   [RFC3579] and [RFC3576].  In Diameter, the attributes are protected
   as specified in [RFC3588].  See those documents for a more detailed
   description.




Congdon, et al.             Standards Track                    [Page 11]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


   The security mechanisms supported in RADIUS and Diameter are focused
   on preventing an attacker from spoofing packets or modifying packets
   in transit.  They do not prevent an authorized RADIUS/Diameter server
   or proxy from inserting attributes with malicious intent.

   VLAN attributes sent by a RADIUS/Diameter server or proxy may enable
   access to unauthorized VLANs.  These vulnerabilities can be limited
   by performing authorization checks at the NAS.  For example, a NAS
   can be configured to accept only certain VLANIDs from a given
   RADIUS/Diameter server/proxy.

   Similarly, an attacker gaining control of a RADIUS/Diameter server or
   proxy can modify the user priority table, causing either degradation
   of quality of service (by downgrading user priority of frames
   arriving at a port), or denial of service (by raising the level of
   priority of traffic at multiple ports of a device, oversubscribing
   the switch or link capabilities).

7.  References

7.1.  Normative References

   [RFC2119]     Bradner, S., "Key words for use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2865]     Rigney, C., Willens, S., Rubens, A., and W. Simpson,
                 "Remote Authentication Dial In User Service (RADIUS)",
                 RFC 2865, June 2000.

   [RFC3588]     Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and
                 J. Arkko, "Diameter Base Protocol", RFC 3588, September
                 2003.

   [RFC3629]     Yergeau, F., "UTF-8, a transformation format of ISO
                 10646", STD 63, RFC 3629, November 2003.

   [RFC4363]     Levi, D. and D. Harrington, "Definitions of Managed
                 Objects for Bridges with Traffic Classes, Multicast
                 Filtering, and Virtual LAN Extensions", RFC 4363,
                 January 2006.

   [IEEE-802]    IEEE Standards for Local and Metropolitan Area
                 Networks:  Overview and Architecture, ANSI/IEEE Std
                 802, 1990.

   [IEEE-802.1D] IEEE Standards for Local and Metropolitan Area
                 Networks: Media Access Control (MAC) Bridges, IEEE Std
                 802.1D-2004, June 2004.



Congdon, et al.             Standards Track                    [Page 12]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


   [IEEE-802.1Q] IEEE Standards for Local and Metropolitan Area
                 Networks: Draft Standard for Virtual Bridged Local Area
                 Networks, P802.1Q-2003, January 2003.

7.2.  Informative References

   [IEEE-802.1X] IEEE Standards for Local and Metropolitan Area
                 Networks: Port based Network Access Control, IEEE Std
                 802.1X-2004, December 2004.

   [RFC2607]     Aboba, B. and J. Vollbrecht, "Proxy Chaining and Policy
                 Implementation in Roaming", RFC 2607, June 1999.

   [RFC2868]     Zorn, G., Leifer, D., Rubens, A., Shriver, J.,
                 Holdrege, M., and I. Goyret, "RADIUS Attributes for
                 Tunnel Protocol Support", RFC 2868, June 2000.

   [RFC3576]     Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B.
                 Aboba, "Dynamic Authorization Extensions to Remote
                 Authentication Dial In User Service (RADIUS)", RFC
                 3576, July 2003.

   [RFC3579]     Aboba, B. and P. Calhoun, "RADIUS (Remote
                 Authentication Dial In User Service) Support For
                 Extensible Authentication Protocol (EAP)", RFC 3579,
                 September 2003.

   [RFC3580]     Congdon, P., Aboba, B., Smith, A., Zorn, G., and J.
                 Roese, "IEEE 802.1X Remote Authentication Dial In User
                 Service (RADIUS) Usage Guidelines", RFC 3580, September
                 2003.

   [RFC4005]     Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
                 "Diameter Network Access Server Application", RFC 4005,
                 August 2005.

   [RFC4072]     Eronen, P., Hiller, T., and G. Zorn, "Diameter
                 Extensible Authentication Protocol (EAP) Application",
                 RFC 4072, August 2005.

8.  Acknowledgements

   The authors would like to acknowledge Joseph Salowey of Cisco, David
   Nelson of Enterasys, Chuck Black of Hewlett-Packard, and Ashwin
   Palekar of Microsoft.






Congdon, et al.             Standards Track                    [Page 13]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


Authors' Addresses

   Paul Congdon
   Hewlett-Packard Company
   HP ProCurve Networking
   8000 Foothills Blvd, M/S 5662
   Roseville, CA  95747

   Phone: +1 916 785 5753
   Fax:   +1 916 785 8478
   EMail: paul.congdon@hp.com


   Mauricio Sanchez
   Hewlett-Packard Company
   HP ProCurve Networking
   8000 Foothills Blvd, M/S 5559
   Roseville, CA  95747

   Phone: +1 916 785 1910
   Fax:   +1 916 785 1815
   EMail: mauricio.sanchez@hp.com


   Bernard Aboba
   Microsoft Corporation
   One Microsoft Way
   Redmond, WA 98052

   Phone: +1 425 706 6605
   Fax:   +1 425 936 7329
   EMail: bernarda@microsoft.com



















Congdon, et al.             Standards Track                    [Page 14]
^L
RFC 4675              VLAN and Priority Attributes        September 2006


Full Copyright Statement

   Copyright (C) The Internet Society (2006).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM 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.

Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.

Acknowledgement

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).







Congdon, et al.             Standards Track                    [Page 15]
^L