draft-ietf-idr-bgp-gr-notification-00.txt   draft-ietf-idr-bgp-gr-notification-01.txt 
Network Working Group K. Patel Network Working Group K.P. Patel
Internet-Draft R. Fernando Internet-Draft R.F. Fernando
Intended status: Standards Track Cisco Systems Intended status: Standards Track Cisco Systems
Expires: June 8, 2012 J. Scudder Expires: October 27, 2013 J.S. Scudder
J. Haas J.H. Haas
Juniper Networks Juniper Networks
December 6, 2011 April 25, 2013
Notification Message support for BGP Graceful Restart Notification Message support for BGP Graceful Restart
draft-ietf-idr-bgp-gr-notification-00.txt draft-ietf-idr-bgp-gr-notification-01.txt
Abstract Abstract
The current BGP Graceful Restart mechanism limits the usage of BGP The current BGP Graceful Restart mechanism limits the usage of BGP
Graceful Restart to BGP protocol messages other than a BGP Graceful Restart to BGP protocol messages other than a BGP
NOTIFICATION message. This document defines an extension to the BGP NOTIFICATION message. This document defines an extension to the BGP
Graceful Restart that permits the Graceful Restart procedures to be Graceful Restart that permits the Graceful Restart procedures to be
performed when the BGP speaker receives a BGP NOTIFICATION Message. performed when the BGP speaker receives a BGP NOTIFICATION Message.
This document also defines a new BGP NOTIFICATION Cease Error subcode This document also defines a new BGP NOTIFICATION Cease Error subcode
to prevent BGP speakers supporting the extension defined in this to prevent BGP speakers supporting the extension defined in this
document from performing a Graceful Restart. document from performing a Graceful Restart.
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 8, 2012. This Internet-Draft will expire on October 27, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
skipping to change at page 3, line 7 skipping to change at page 2, line 25
modifications of such material outside the IETF Standards Process. modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Modifications to BGP Graceful Restart Capability . . . . . . . 4 2. Modifications to BGP Graceful Restart Capability . . . . . . 3
3. BGP Hard Reset Subcode . . . . . . . . . . . . . . . . . . . . 5 3. BGP Hard Reset Subcode . . . . . . . . . . . . . . . . . . . 4
4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
For many classes of errors, the BGP protocol must send a NOTIFICATION For many classes of errors, the BGP protocol must send a NOTIFICATION
message and reset the peering session to handle the error condition. message and reset the peering session to handle the error condition.
The BGP Graceful Restart extension defined in [RFC4724] requires that The BGP Graceful Restart extension defined in [RFC4724] requires that
normal BGP procedures defined in [RFC4271] be followed when a normal BGP procedures defined in [RFC4271] be followed when a
NOTIFICATION message is sent or received. This document defines an NOTIFICATION message is sent or received. This document defines an
extension to BGP Graceful Restart that permits the Graceful Restart extension to BGP Graceful Restart that permits the Graceful Restart
procedures to be performed when the BGP speaker receives a procedures to be performed when the BGP speaker receives a
skipping to change at page 4, line 32 skipping to change at page 3, line 19
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
2. Modifications to BGP Graceful Restart Capability 2. Modifications to BGP Graceful Restart Capability
The BGP Graceful Restart Capability is augmented to signal the The BGP Graceful Restart Capability is augmented to signal the
Graceful Restart support for BGP NOTIFICATION messages. In Graceful Restart support for BGP NOTIFICATION messages. In
particular, the flags field for Address Family is augmented as particular, the Restart flags field and the Flags field for Address
follows: Family are augmented as follows:
+--------------------------------------------------+ +--------------------------------------------------+
| Restart Flags (4 bits) | | Restart Flags (4 bits) |
+--------------------------------------------------+ +--------------------------------------------------+
| Restart Time in seconds (12 bits) | | Restart Time in seconds (12 bits) |
+--------------------------------------------------+ +--------------------------------------------------+
| Address Family Identifier (16 bits) | | Address Family Identifier (16 bits) |
+--------------------------------------------------+ +--------------------------------------------------+
| Subsequent Address Family Identifier (8 bits) | | Subsequent Address Family Identifier (8 bits) |
+--------------------------------------------------+ +--------------------------------------------------+
| Flags for Address Family (8 bits) | | Flags for Address Family (8 bits) |
+--------------------------------------------------+ +--------------------------------------------------+
| ... | | ... |
+--------------------------------------------------+ +--------------------------------------------------+
| Address Family Identifier (16 bits) | | Address Family Identifier (16 bits) |
+--------------------------------------------------+ +--------------------------------------------------+
| Subsequent Address Family Identifier (8 bits) | | Subsequent Address Family Identifier (8 bits) |
+--------------------------------------------------+ +--------------------------------------------------+
| Flags for Address Family (8 bits) | | Flags for Address Family (8 bits) |
+--------------------------------------------------+ +--------------------------------------------------+
Flags for Address Family: Restart Flags:
This field contains bit flags relating to routes that were This field contains bit flags relating to restart.
advertised with the given AFI and SAFI.
0 1 2 3 4 5 6 7 0 1 2 3
+-+-+-+-+-+-+-+-+ +-+-+-+-+
|F|N| Reserved | |R|N| |
+-+-+-+-+-+-+-+-+ +-+-+-+-+
The second most significant bit "N" is defined as a BGP Graceful The second most significant bit "N" is defined as a BGP Graceful
Notification bit, which is used to indicate the Graceful Restart Notification bit, which is used to indicate the Graceful Restart
support for BGP NOTIFICATION messages. BGP speaker indicates the support for BGP NOTIFICATION messages. BGP speaker indicates the
Graceful Restart support for BGP NOTIFICATION messages and its Graceful Restart support for BGP NOTIFICATION messages and its
ability to handle the new BGP NOTIFICATION Cease message subcode and ability to handle the new BGP NOTIFICATION Cease message subcode and
the format for a BGP NOTIFICATION Cease message defined in [RFC4486] the format for a BGP NOTIFICATION Cease message defined in [RFC4486]
when the Graceful NOTIFICATION bit is set (value 1). when the Graceful NOTIFICATION bit is set (value 1).
Flags for Address Family:
This field contains bit flags relating to routes that were
advertised with the given AFI and SAFI.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|F|N| Reserved |
+-+-+-+-+-+-+-+-+
The usage of second most significant bit "N" is deprecated. This bit
SHOULD be reserved and set to 0.
3. BGP Hard Reset Subcode 3. BGP Hard Reset Subcode
A new BGP Cease message subcode is defined known as BGP Hard Reset A new BGP Cease message subcode is defined known as BGP Hard Reset
Subcode. The value of this subcode is 9. Subcode. The value of this subcode is 9.
Whenever a BGP speaker receives a NOTIFICATION message with the Cease Whenever a BGP speaker receives a NOTIFICATION message with the Cease
Error code and Hard Reset Error subcode, the speaker MUST terminate Error code and Hard Reset Error subcode, the speaker MUST terminate
the BGP session following the standard procedures in [RFC4271]. the BGP session following the standard procedures in [RFC4271].
4. Operation 4. Operation
A BGP speaker that is willing to receive and send BGP NOTIFICATION A BGP speaker that is willing to receive and send BGP NOTIFICATION
messages in Graceful mode should advertise the BGP Graceful messages in Graceful mode SHOULD advertise the BGP Graceful
Notification Flag "N" using the Graceful Restart Capability as Notification Flag "N" using the Graceful Restart Capability as
defined in [RFC4724]. defined in [RFC4724].
When a BGP Speaker receives a BGP NOTIFICATION message, it SHOULD When a BGP Speaker receives a BGP NOTIFICATION message, it SHOULD
follow the standard rules of the receiving speaker mentioned in follow the standard rules of the receiving speaker mentioned in
[RFC4724] for all AFI/SAFIs for which it has announced the BGP [RFC4724] for all AFI/SAFIs for which it has announced the BGP
Graceful Notification flag. The BGP speaker generating a BGP Graceful Notification flag. The BGP speaker generating a BGP
NOTIFICATION message SHOULD follow the standard rules of the NOTIFICATION message SHOULD follow the standard rules of the
receiving Speaker in [RFC4724] for all AFI/SAFIs that were announced receiving Speaker in [RFC4724] for all AFI/SAFIs that were announced
with the BGP Graceful Notification flag. with the BGP Graceful Notification flag.
A BGP speaker MAY continue to operate in the Graceful Restart mode
even if it receives a Graceful Restart capability without a Graceful
Notification Flag.
When a BGP speaker resets its session due to a HOLDTIME expiry, it
SHOULD follow the standard rules of the receiving speaker mentioned
in [RFC4724] aside from generating a BGP NOTIFICATION message as
mentioned in [RFC4271].
Once the session is re-established, both BGP speakers MUST set their Once the session is re-established, both BGP speakers MUST set their
"Forwarding State" bit to 1 if they want to apply planned graceful "Forwarding State" bit to 1 if they want to apply planned graceful
restart. The handling of the "Forwarding State" bit should be done restart. The handling of the "Forwarding State" bit should be done
as specified by the procedures of the Receiving speaker in [RFC4724] as specified by the procedures of the Receiving speaker in [RFC4724]
are applied. are applied.
As part of this extension, possible consecutive restarts SHOULD NOT As part of this extension, any possible consecutive restarts SHOULD
delete a route (from the peer) previously marked as stale, until NOT delete a route (from the peer) previously marked as stale, until
required by rules mentioned in [RFC4724]. required by rules mentioned in [RFC4724].
5. Acknowledgements 5. Acknowledgements
The authors would like to thank Robert Raszuk for the review and The authors would like to thank Robert Raszuk for the review and
comments. comments.
6. IANA Considerations 6. IANA Considerations
This document defines a new BGP Cease message subcode known as BGP This document defines a new BGP Cease message subcode known as BGP
Hard Reset Subcode. IANA mantains the list of existing BGP Cease Hard Reset Subcode. IANA mantains the list of existing BGP Cease
message subcodes. This document proposes defining a new BGP Cease message subcodes. This document proposes defining a new BGP Cease
message subcode known as BGP Hard Reset Subcode with the value 9. message subcode known as BGP Hard Reset Subcode with the value 9.
7. Security Considerations 7. Security Considerations
This extension to BGP does not change the underlying security issues This extension to BGP does not change the underlying security issues
inherent in the existing [RFC4724] and [RFC4271] inherent in the existing [RFC4724] and [RFC4271]
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2842] Chandra, R. and J. Scudder, "Capabilities Advertisement [RFC2842] Chandra, R. and J. Scudder, "Capabilities Advertisement
with BGP-4", RFC 2842, May 2000. with BGP-4", RFC 2842, May 2000.
[RFC3392] Chandra, R. and J. Scudder, "Capabilities Advertisement [RFC3392] Chandra, R. and J. Scudder, "Capabilities Advertisement
with BGP-4", RFC 3392, November 2002. with BGP-4", RFC 3392, November 2002.
 End of changes. 19 change blocks. 
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