summaryrefslogtreecommitdiff
path: root/doc/rfc/rfc1954.txt
blob: d82f75b0f42d808d400130c362479ce11ac44956 (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
Network Working Group                                 P. Newman, Ipsilon
Request for Comments: 1954                         W. L. Edwards, Sprint
Category: Informational                               R. Hinden, Ipsilon
                                                     E. Hoffman, Ipsilon
                                                  F. Ching Liaw, Ipsilon
                                                        T. Lyon, Ipsilon
                                                    G. Minshall, Ipsilon
                                                                May 1996


          Transmission of Flow Labelled IPv4 on ATM Data Links
                          Ipsilon Version 1.0

Status of this Memo

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

IESG Note:

   This note documents a private protocol for IPv4-based flows.  This
   protocol is NOT the product of an IETF working group nor is it a
   standards track document. It has not necessarily benefited from the
   widespread and in depth community review that standards track
   documents receive.

Abstract

   This document specifies the manner for transmitting IPv4 datagrams
   over an ATM data link, both in a default manner and in the presence
   of flow labelling via Ipsilon Flow Management Protocol [IFMP].

Table of Contents

   Introduction....................................................2
   1. Labels.......................................................2
   2. Default Encapsulation........................................2
   3. Flow Type 0 Encapsulation....................................3
   4. Flow Type 1 Encapsulation....................................4
   5. Flow Type 2 Encapsulation....................................5
   References......................................................7
   Security Considerations.........................................7
   Authors' Addresses..............................................7







Newman, et. al.              Informational                      [Page 1]
^L
RFC 1954               Flow Labelled IPv4 on ATM                May 1996


Introduction

   This document specifies the manner for transmitting IPv4 datagrams
   over an ATM data link, both in a default manner and in the presence
   of flow labelling via Ipsilon Flow Management Protocol [IFMP].  ATM
   specific functions such as OAM cells, the CLP bit, and ABR RM cells
   are not used.  There are no reserved VCIs other than VPI = 0, VCI =
   0, which indicates an unassigned cell; and VPI = 0, VCI = 15, which
   is used for the default encapsulation.  IFMP messages must be sent
   using the default encapsulation.

1. Labels

   Labels, as carried by IFMP, are realized on an ATM data link as
   specific VPI/VCIs.  The format of the Label field for ATM labels is:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Reservd|          VPI          |             VCI               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The low order 16 bits of the label correspond to the VCI, with the
   least significant bit of the Label field corresponding to the least
   significant bit of the VCI.  If the link cannot support a full 16 bit
   VCI the unused bits of the VCI must be the most significant bits and
   they must be set to zero.

   The next 12 higher order bits of the label correspond to the VPI,
   with the least significant of these bits corresponding to the least
   significant bit of the VPI.  If the link cannot support a full 12 bit
   VPI, then the unused bits of the VPI must be the most significant
   bits and they must be set to zero.  The most significant four bits of
   the label are reserved.  They should be set to zero by the sender and
   ignored by the receiver.

2. Default Encapsulation

   The default encapsulation for IPv4 packets on ATM data links is the
   LLC/SNAP encapsulation specified in section 4.1 "LLC encapsulation
   for routed protocols" of RFC 1483 [RFC1483].  Such frames begin with
   the octets 0xAA 0xAA 0x03 0x00 0x00 0x00 0x08 0x00 (the LLC/SNAP
   header for IPv4).  The LLC/SNAP header is prefixed to the IP datagram
   and the entire packet is encapsulated within the payload of an AAL-5
   CPCS-PDU as specified in RFC 1483 and illustrated below:






Newman, et. al.              Informational                      [Page 2]
^L
RFC 1954               Flow Labelled IPv4 on ATM                May 1996


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               LLC (0xAA-AA-03)                |               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               |
   |                   SNAP (0x00-00-00-08-00)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                         IPv4 Datagram                         ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   Pad (0 - 47 octets)                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +               AAL-5 CPCS-PDU Trailer (8 octets)               +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The maximum transmission unit (MTU) of an IPv4 datagram using the
   default encapsulation is 1500 octets.

   Frames using the default encapsulation are sent to: VPI = 0, VCI =
   15.

3. Flow Type 0 Encapsulation

   All IPv4 frames using Flow Type 0 are encapsulated within the payload
   of an AAL-5 CPCS-PDU.  This is the null encapsulation of section 5.1
   "VC based multiplexing of routed protocols" from RFC 1483 [RFC1483].
   There is no LLC/SNAP header.  The first octet of the frame
   corresponds to the first octet of the IPv4 datagram (i.e., the octet
   that contains the IP version number (4) and Internet Header Length
   (IHL) ).  The IP datagram is encapsulated within the payload of an
   AAL-5 CPCS-PDU as specified in RFC 1483 and illustrated below:

















Newman, et. al.              Informational                      [Page 3]
^L
RFC 1954               Flow Labelled IPv4 on ATM                May 1996


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                         IPv4 Datagram                         ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Pad (0 - 47 octets)                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +                AAL-5 CPCS-PDU Trailer (8 octets)              +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The MTU of an IPv4 datagram using Flow Type 0 encapsulation is 1500
   octets.

   Frames using Flow Type 0 encapsulation are sent to the VPI/VCI
   specified in the Label field of the corresponding IFMP Flow Type 0
   Redirect message element [IFMP].

4. Flow Type 1 Encapsulation

   All IPv4 frames using Flow Type 1 are encapsulated directly in the
   payload of an AAL-5 CPCS-PDU.  This is the null encapsulation of
   section 5.1 "VC based multiplexing of routed protocols" from RFC 1483
   [RFC1483].  There is no LLC/SNAP header.  Also, the following fields
   of the IP header are not transmitted: Version, Internet Header Length
   (IHL), Type of Service (TOS), Time to Live (TTL), Protocol, Source
   Address, and Destination Address.  In addition, the first 4 octets
   immediately following the IP header (as determined by the IHL field)
   are not transmitted.  (These 4 octets correspond to the source and
   destination ports for TCP and UDP datagrams.)  The value of the Total
   Length field is not changed; it remains the total length of the IP
   datagram before the above fields were removed.  The transmitted value
   of the Checksum field is the checksum value that would have been
   computed for the entire IP header if the TTL field had been set to
   zero (i.e., the actual value of the TTL field is "subtracted", using
   one's-complement arithmetic, from the Checksum before transmission).

   The IP datagram is encapsulated within the payload of an AAL-5 CPCS-
   PDU as specified in RFC 1483 and illustrated below:









Newman, et. al.              Informational                      [Page 4]
^L
RFC 1954               Flow Labelled IPv4 on ATM                May 1996


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Total Length          |        Identification         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Flags|     Fragment Offset     |           Checksum            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                             Data                              ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Pad (0 - 47 octets)                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +                AAL-5 CPCS-PDU Trailer (8 octets)              +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The MTU of the IPv4 datagram using Flow Type 1 encapsulation is 1484
   octets (1500 octets minus the 16 octets specified above).

   Frames using Flow Type 1 encapsulation are sent to the VPI/VCI
   specified in the Label field of the corresponding IFMP Flow Type 1
   redirect message element [IFMP].

5. Flow Type 2 Encapsulation

   All IPv4 frames using Flow Type 2 are encapsulated directly in the
   payload of an AAL-5 CPCS-PDU.  This is the null encapsulation of
   section 5.1 "VC based multiplexing of routed protocols" from RFC 1483
   [RFC1483].  There is no LLC/SNAP header.  Also, the following fields
   of the IP header are not transmitted: Version, Internet Header Length
   (IHL), Time to Live (TTL), Source Address, and Destination Address.
   The first 4 octets immediately following the IP header (as determined
   by the IHL field) are transmitted.  (These 4 octets correspond to the
   source and destination ports for TCP and UDP datagrams.) The value of
   the Total Length field is not changed; it remains the total length of
   the IP datagram before the above fields were removed.  The
   transmitted value of the Checksum field is the checksum value that
   would have been computed for the entire IP header if the TTL field
   had been set to zero (i.e., the actual value of the TTL field is
   "subtracted", using one's-complement arithmetic, from the Checksum
   before transmission).

   The IP datagram is encapsulated within the payload of an AAL-5 CPCS-
   PDU as specified in RFC 1483 and illustrated below:





Newman, et. al.              Informational                      [Page 5]
^L
RFC 1954               Flow Labelled IPv4 on ATM                May 1996


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Reserved    |Type of Service|         Total Length          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Identification         |Flags|     Fragment Offset     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Reserved    |   Protocol    |           Checksum            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                             Data                              ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Pad (0 - 47 octets)                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +                AAL-5 CPCS-PDU Trailer (8 octets)              +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Reserved fields are not used and should be set to zero by the
   sender and ignored by the receiver.

   The MTU of the IPv4 datagram using Flow Type 2 encapsulation is 1492
   octets (1500 octets minus the 8 octets specified above).

   Frames using Flow Type 2 encapsulation are sent to the VPI/VCI
   specified in the Label field of the corresponding IFMP Flow Type 2
   redirect message element [IFMP].






















Newman, et. al.              Informational                      [Page 6]
^L
RFC 1954               Flow Labelled IPv4 on ATM                May 1996


References

      [IFMP] Newman, P., et. al., "Ipsilon Flow Management Protocol
                Specification for IPv Version 1.0", Ipsilon Networks
                Inc., RFC 1953, May 1996.

      [RFC1483] Heinanen, J., "Multiprotocol Encapsulation over ATM
                Adaptation Layer 5", RFC 1483, July 1993.

SECURITY CONSIDERATIONS

   Security issues are not discussed in this document.

AUTHORS' ADDRESSES

   Peter Newman                        Phone: +1 (415) 846-4603
   Ipsilon Networks, Inc.              EMail: pn@ipsilon.com

   W. L. Edwards, Chief Scientist      Phone:  +1 (913) 534 5334
   Sprint                              EMail:  texas@sprintcorp.com

   Robert M. Hinden                    Phone: +1 (415) 846-4604
   Ipsilon Networks, Inc.              EMail: hinden@ipsilon.com

   Eric Hoffman                        Phone: +1 (415) 846-4610
   Ipsilon Networks, Inc.              EMail: hoffman@ipsilon.com

   Fong Ching Liaw                     Phone: +1 (415) 846-4607
   Ipsilon Networks, Inc.              EMail: fong@ipsilon.com

   Tom Lyon                            Phone: +1 (415) 846-4601
   Ipsilon Networks, Inc.              EMail: pugs@ipsilon.com

   Greg Minshall                       Phone: +1 (415) 846-4605
   Ipsilon Networks, Inc.              EMail: minshall@ipsilon.com
















Newman, et. al.              Informational                      [Page 7]
^L
RFC 1954               Flow Labelled IPv4 on ATM                May 1996


Ipsilon Networks, Inc. is located at:

   2191 East Bayshore Road
   Suite 100
   Palo Alto, CA 94303
   USA

Sprint is located at:

   Sprint
   Sprint Technology Services - Long Distance Division
   9300 Metcalf Avenue
   Mailstop KSOPKB0802
   Overland Park, KS 66212-6333
   USA




































Newman, et. al.              Informational                      [Page 8]
^L