Network working group Q. Zeng
Internet Draft J. Dong
Intended status: Standards Track Huawei Technologies
Expires: April 2011 Z. Huang
China Telecom
October 22, 2010
One-time Address-Prefix Based Outbound Route Filter for BGP-4
draft-zeng-one-time-prefix-orf-01.txt
Abstract
This document defines a new Outbound Router Filter (ORF) type for
BGP, termed "One-time Address Prefix Outbound Route Filter", which
would allow a BGP speaker to send to its BGP peer a route refresh
request with a set of address-prefix-based filters to make the peer
re-advertise only the specific routes matching the filters to the
speaker. This ORF-type enables a BGP speaker to recover some
specific "problematic" routes without requiring its peer to re-
advertise the whole Adj-RIB-Out of specific address family, which
makes the trouble shooting operation (such as packets tracking) more
efficient and reduces the impact on network stability. This filter
does not change the outbound route filters on BGP peers and should
only be used for one-time filtering.
Status of this Memo
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This Internet-Draft will expire on April 22, 2011.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Conventions used in this document
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 [RFC2119].
Table of Contents
1. Introduction................................................2
2. One-time Address Prefix ORF-Type............................3
3. Operation...................................................4
4. Security Considerations.....................................4
5. IANA Considerations.........................................4
6. Acknowledgments.............................................4
7. References..................................................4
7.1. Normative References...................................4
Authors' Addresses.............................................6
1. Introduction
The Outbound Route Filtering Capability defined in [RFC5291]
provides a mechanism for a BGP speaker to send to its BGP peer a set
of Outbound Route Filters (ORFs) that can be used by its peer to
filter its outbound routing updates to the speaker.
During some network maintenance, BGP speaker only needs to retrieve
some specific "problematic" routes from its peer if the routes are
possibly lost or contain some problematic attributes for some reason,
but send ROUTE-REFRESH will lead to the peer re-advertising its
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whole Adj-RIB-Out. Such large numbers of updates include a lot of
unnecessary routes which would make trouble shooting operation (such
as packets tracking) more difficult, and is a waste of processing
resources and bandwidth. With the increase of IPV6 deployment, this
problem could be more significant. Even configured with ORF
mechanism as defined in [RFC5291], on receipt of a ROUTE-REFRESH
message, the peer will re-advertise all the routes matching current
outbound route filters, i.e., the whole Adj-Rib-Out for this BGP
speaker. Since in this case the BGP speaker does not want to change
the outbound route filters on its peer, this problem cannot be
solved by current ORF mechanism.
This document defines a new Outbound Router Filter (ORF) type for
BGP, termed "One-time Address Prefix Outbound Route Filter", which
would allow a BGP speaker to send to its BGP peer a route refresh
request with a set of address-prefix-based filters to make the peer
re-advertise only the specific routes matching the filters to the
speaker. This ORF-type enables a BGP speaker to recover some
specific "problematic" routes without requiring its peer to re-
advertise the whole Adj-RIB-Out of specific address family, which
makes the trouble shooting operation (such as packets tracking) more
efficient and reduces the impact on network stability. This filter
does not change the outbound route filters on BGP peers and should
only be used for one-time filtering.
2. One-time Address Prefix ORF-Type
This document defines a new ORF type: One-time Address Prefix ORF.
As specified in the [RFC5291], an ORF entry is a tuple of the form
<AFI/SAFI, ORF-Type, Action, Match, ORF-value> an ORF consists of
one or more ORF entries that have a common AFI/SAFI and ORF-Type. An
ORF is identified by <AFI/SAFI, ORF-Type>.
The format of One-time Address Prefix ORF-Type entry is the same as
the encoding of Address Prefix ORF in [RFC5292], the specific fields
are defined as follows:
Since the semantics of this new ORF-Type is always "one-time
filtering" and has no impact on existing ORFs, so the Action field
MUST be ignored.
The matching rules of the One-time Address Prefix ORF are the same
as defined in Address-Prefix-Based ORF [RFC-5292].
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The ORF entries of this type are used as one-time filters that MUST
not change any previously installed ORF entry on the remote peer.
3. Operation
The capability negotiation of <AFI/SAFI, One-time Address Prefix
ORF> MUST NOT delay the advertisement of routes with this AFI/SAFI.
The received One-time Address Prefix ORF entries SHOULD only be used
for one-time route filtering and MUST NOT be saved locally. The
received One-time Address Prefix ORF entries MUST NOT modify the
outbound route filters on the receiver (either locally configured or
received from peer through ORF).
On receipt of ROUTE-REFRESH message with One-time Address Prefix ORF
entries, the receiver SHOULD re-advertise to the peer the routes
from the Adj-RIB-Out associated with the peer which pass the entries
carried in the One-time Address Prefix ORF and taking into account
the locally saved ORFs (if any) received from the peer.
4. Security Considerations
This extension to BGP does not change the underlying security issues
in [RFC4271].
5. IANA Considerations
This document specifies a new Outbound Route Filtering (ORF) type,
One-time Address-Prefix ORF. The value of the ORF-type needs to be
assigned by the IANA.
6. Acknowledgments
The authors would like to thank Keyur Patel, Enke Chen, Rob Shakir,
Susan Hares, Haibo Wang, Jiawei Dong, Yaqun Xiao, Mach Chen for
their valuable suggestions and comments to this document.
7. References
7.1. Normative References
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC2918] Chen, E., "Route Refresh Capability for BGP-4", RFC 2918,
September 2000.
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[RFC5291] Chen, E. and Y. Rekhter, "Outbound Route Filtering
Capability for BGP-4", RFC 5291, August 2008.
[RFC5292] Chen, E. and S. Sangli, "Address-Prefix-Based Outbound
Route Filter for BGP-4", RFC 5292, August 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of
Standards Track Code Points", BCP 100, RFC 4020, February
2005.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
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Authors' Addresses
Qing Zeng
Huawei Technologies Co.,Ltd.
Huawei Building, No.3 Xinxi Rd.,
Hai-Dian District
Beijing, 100085
P.R. China
Email: zengqing@huawei.com
Jie Dong
Huawei Technologies Co.,Ltd.
Huawei Building, No.3 Xinxi Rd.,
Hai-Dian District
Beijing, 100085
P.R. China
Email: dongjie_dj@huawei.com
ZhiLan Huang
China Telecom
109 West Zhongshan Ave,
Tianhe District, Guanghou, 510630, P.R.C
Email: huangzl@gsta.com
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