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
|
Network Working Group E. Chen
Request for Comments: 4486 Cisco Systems
Category: Standards Track V. Gillet
France Telecom
April 2006
Subcodes for BGP Cease Notification Message
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 defines several subcodes for the BGP Cease NOTIFICATION
message that would provide more information to aid network operators
in correlating network events and diagnosing BGP peering issues.
1. Introduction
This document defines several subcodes for the BGP Cease NOTIFICATION
message that would provide more information to aid network operators
in correlating network events and diagnosing BGP peering issues. It
also recommends that a BGP speaker implement a backoff mechanism in
re-trying a BGP connection after the speaker receives a NOTIFICATION
message with certain CEASE subcode.
2. Specification of Requirements
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 [RFC-2119].
Chen & Gillet Standards Track [Page 1]
^L
RFC 4486 BGP Cease Notification Message Subcodes April 2006
3. Subcode Definition
The following subcodes are defined for the Cease NOTIFICATION
message:
Subcode Symbolic Name
1 Maximum Number of Prefixes Reached
2 Administrative Shutdown
3 Peer De-configured
4 Administrative Reset
5 Connection Rejected
6 Other Configuration Change
7 Connection Collision Resolution
8 Out of Resources
4. Subcode Usage
If a BGP speaker decides to terminate its peering with a neighbor
because the number of address prefixes received from the neighbor
exceeds a locally configured upper bound (as described in [BGP-4]),
then the speaker MUST send to the neighbor a NOTIFICATION message
with the Error Code Cease and the Error Subcode "Maximum Number of
Prefixes Reached". The message MAY optionally include the Address
Family information [BGP-MP] and the upper bound in the "Data" field,
as shown in Figure 1, where the meaning and use of the <AFI, SAFI>
tuple is the same as defined in [BGP-MP], Section 7.
+-------------------------------+
| AFI (2 octets) |
+-------------------------------+
| SAFI (1 octet) |
+-------------------------------+
| Prefix upper bound (4 octets) |
+-------------------------------+
Figure 1: Optional Data Field
If a BGP speaker decides to administratively shut down its peering
with a neighbor, then the speaker SHOULD send a NOTIFICATION message
with the Error Code Cease and the Error Subcode "Administrative
Shutdown".
If a BGP speaker decides to de-configure a peer, then the speaker
SHOULD send a NOTIFICATION message with the Error Code Cease and the
Error Subcode "Peer De-configured".
Chen & Gillet Standards Track [Page 2]
^L
RFC 4486 BGP Cease Notification Message Subcodes April 2006
If a BGP speaker decides to administratively reset the peering with a
neighbor, then the speaker SHOULD send a NOTIFICATION message with
the Error Code Cease and the Error Subcode "Administrative Reset".
If a BGP speaker decides to disallow a BGP connection (e.g., the peer
is not configured locally) after the speaker accepts a transport
protocol connection, then the BGP speaker SHOULD send a NOTIFICATION
message with the Error Code Cease and the Error Subcode "Connection
Rejected".
If a BGP speaker decides to administratively reset the peering with a
neighbor due to a configuration change other than the ones described
above, then the speaker SHOULD send a NOTIFICATION message with the
Error Code Cease and the Error Subcode "Other Configuration Change".
If a BGP speaker decides to send a NOTIFICATION message with the
Error Code Cease as a result of the collision resolution procedure
(as described in [BGP-4]), then the subcode SHOULD be set to
"Connection Collision Resolution".
If a BGP speaker runs out of resources (e.g., memory) and decides to
reset a session, then the speaker MAY send a NOTIFICATION message
with the Error Code Cease and the Error Subcode "Out of Resources".
It is RECOMMENDED that a BGP speaker behave as though the
DampPeerOscillations attribute [BGP-4] were true for this peer when
re-trying a BGP connection after the speaker receives a Cease
NOTIFICATION message with a subcode of "Administrative Shutdown",
"Peer De-configured", "Connection Rejected", or "Out of Resources".
An implementation SHOULD impose an upper bound on the number of
consecutive automatic retries. Once this bound is reached, the
implementation would stop re-trying any BGP connections until some
administrative intervention, i.e., set the AllowAutomaticStart
attribute [BGP-4] to FALSE.
5. IANA Considerations
This document defines the subcodes 1 - 8 for the BGP Cease
NOTIFICATION message. Future assignments are to be made using either
the Standards Action process defined in [RFC-2434], or the Early IANA
Allocation process defined in [RFC-4020]. Assignments consist of a
name and the value.
6. Security Considerations
This extension to BGP does not change the underlying security issues
inherent in the existing BGP.
Chen & Gillet Standards Track [Page 3]
^L
RFC 4486 BGP Cease Notification Message Subcodes April 2006
7. Acknowledgements
The authors would like to thank Yakov Rekhter, Pedro Marques, Andrew
Lange, and Don Goodspeed for their review and suggestions.
8. References
8.1. Normative References
[BGP-4] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[BGP-MP] Bates, T., Rekhter, Y., Chandra, R., and D. Katz,
"Multiprotocol Extensions for BGP-4", RFC 2858, June 2000.
[RFC-2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[RFC-2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[RFC-4020] Kompella, K. and A. Zinin, "Early IANA Allocation of
Standards Track Code Points", BCP 100, RFC 4020, February
2005.
Chen & Gillet Standards Track [Page 4]
^L
RFC 4486 BGP Cease Notification Message Subcodes April 2006
Authors' Addresses
Enke Chen
Cisco Systems, Inc.
170 W. Tasman Dr.
San Jose, CA 95134
USA
EMail: enkechen@cisco.com
Vincent Gillet
France Telecom Longues Distances
61, rue des Archives
75003 Paris FRANCE
EMail: vgi@opentransit.net
Chen & Gillet Standards Track [Page 5]
^L
RFC 4486 BGP Cease Notification Message Subcodes April 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).
Chen & Gillet Standards Track [Page 6]
^L
|
