One document matched: draft-dong-idr-te-lsp-distribution-00.txt
Network Working Group J. Dong
Internet-Draft M. Chen
Intended status: Standards Track Huawei Technologies
Expires: April 18, 2013 October 15, 2012
Distribution of MPLS Traffic Engineering (TE) LSP State using BGP
draft-dong-idr-te-lsp-distribution-00
Abstract
This document describes a mechanism to collect the Traffic
Engineering (TE) LSP information using BGP. Such information can be
used by external components for path reoptimization, service
placement and network visualization.
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 RFC 2119 [RFC2119].
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on April 18, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
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carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Carrying LSP State Information in BGP . . . . . . . . . . . . . 4
2.1. LSP Information NLRI . . . . . . . . . . . . . . . . . . . 4
2.2. LSP State Attribute . . . . . . . . . . . . . . . . . . . . 6
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1. Normative References . . . . . . . . . . . . . . . . . . . 7
6.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
In some network environments, the states of established Multi-
Protocol Label Switching (MPLS) Traffic Engineering (TE) Label
Switched Paths (LSPs) in the network are required by some components
external to the network domain. Usually this information is directly
maintained by the ingress Label Edge Routers (LERs) of the MPLS TE
LSPs.
One example of using the LSP information is stateful Path Computation
Element (PCE) [I-D.ietf-pce-stateful-pce], which could provide
benefits in path reoptimization . While some extensions are proposed
in Path Computation Element Communication Protocol (PCEP) for the
Path Computation Clients (PCCs) to report the LSP states to the PCE,
this mechanism may not be applicable in a management-based PCE
architecture as specified in section 5.5 of [RFC4655]. As
illustrated in the figure below, the PCC is not an LSR in the routing
domain, thus the head-end nodes of the TE-LSP may not implement the
PCEP protocol. In this case some general mechanism to collect the
TE-LSP states from the ingress LERs is needed. This document
proposes an LSP state collection mechanism complementary to the
mechanism defined in [I-D.ietf-pce-stateful-pce].
-----------
| ----- |
Service | | TED |<-+----------->
Request | ----- | TED synchronization
| | | | mechanism (for example,
v | | | routing protocol)
------------- Request/ | v |
| | Response| ----- |
| NMS |<--------+> | PCE | |
| | | ----- |
------------- -----------
Service |
Request |
v
---------- Signaling ----------
| Head-End | Protocol | Adjacent |
| Node |<---------->| Node |
---------- ----------
Figure 1. Management-Based PCE Usage
In networks with composite PCE nodes as specified in section 5.1 of
[RFC4655], the PCE is implemented on some routers in the network, and
the PCCs in the network can use the mechanism described in
[I-D.ietf-pce-stateful-pce] to report the LSP information to the PCE
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nodes. An external component may further need to collect the LSP
information from all the PCEs in the network to get a global view of
the LSP states in the network.
In some networks, a centralized controller is used for service
placement. Obtaining the TE LSP state information is quite important
for making appropriate service placement decisions with the purpose
of both meeting the application's requirements and utilizing the
network resource efficiently.
The Network Management System (NMS) may need to provide global
visibility of the TE LSPs in the network as part of the network
visualization.
BGP has been extended to distribute link-state and traffic
engineering information and share with some external components
[I-D.ietf-idr-ls-distribution]. Using the same protocol to collect
other network layer information would be desired by the external
components, which avoids introducing multiple protocols for network
information collection. This document describes a mechanism to
distribute the TE LSP information to external components using BGP.
2. Carrying LSP State Information in BGP
2.1. LSP Information NLRI
A new NLRI "LSP Information NLRI" is advertised in BGP UPDATE
messages using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes
[RFC4760]. The AFI value is TBD, the SAFI value can be 1 for LSPs in
the public network. BGP speakers that wish to exchange LSP
Information NLRI MUST use the BGP Multiprotocol Extensions Capability
Code (1) to advertise the corresponding (AFI, SAFI) pair, as
specified in [RFC4760].
The format of the LSP Information NLRI is as follows:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NLRI-Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP-IDENTIFIER (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2. LSP Information NLRI
The NLRI-Type field can be one of the following values:
o NLRI-Type = 1: IPv4 LSP NLRI
o NLRI-Type = 2: IPv6 LSP NLRI
If the NLRI-Type value is set to 1, the LSP-IDENTIFIER is the IPv4-
LSP-IDENTIFER structured as 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Tunnel Sender Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel ID | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Tunnel End-point Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3. IPv4-LSP-IDENTIFIER
If the NLRI-Type value is set to 2, the LSP-IDENTIFIER is the IPv6-
LSP-IDENTIFIER structured as below:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| IPv6 Tunnel Sender Address |
+ (16 octets) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel ID | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| IPv6 Tunnel End-point Address |
+ (16 octets) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4. IPv6-LSP-IDENTIFIER
The fields in the IPv4-LSP-IDENTIFIER and IPv6-LSP-IDENTIFIER are the
same as specified in [RFC3209].
2.2. LSP State Attribute
The LSP State Attribute is an optional non-transitive BGP attribute
which is used to describe the characteristics of the LSPs. The LSP
State Attribute consists of a set of objects defined in [RFC3209],
[RFC3473] and [RFC5440] . This Attribute SHOULD only be used with
the LSP Information NLRI.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Objects (variable) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5. LSP State Attribute
Currently the Objects that can be carried in the LSP State Attribute
include:
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o LSP Attributes (LSPA) Object
o Explicit Route Object (ERO)
o Record Route Object (RRO)
o BANDWIDTH Object
o METRIC Object
o Protection Object
o Admin Status Object
Other Objects may also be carried in the LSP State Attribute, which
would be specified in a future version.
3. IANA Considerations
IANA needs to assign a new AFI value for the LSP Information NLRI.
This code point will come from the "Address Family Numbers" registry.
IANA needs to assign an new code point for the LSP State Attribute
from the "BGP Path Attributes" registry.
4. Security Considerations
TBD
5. Acknowledgements
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Resource ReserVation Protocol-Traffic
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Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
January 2007.
[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element
(PCE) Communication Protocol (PCEP)", RFC 5440,
March 2009.
6.2. Informative References
[I-D.ietf-idr-ls-distribution]
Gredler, H., Medved, J., Previdi, S., and A. Farrel,
"North-Bound Distribution of Link-State and TE Information
using BGP", draft-ietf-idr-ls-distribution-00 (work in
progress), September 2012.
[I-D.ietf-pce-stateful-pce]
Crabbe, E., Medved, J., Varga, R., and I. Minei, "PCEP
Extensions for Stateful PCE",
draft-ietf-pce-stateful-pce-01 (work in progress),
July 2012.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
Authors' Addresses
Jie Dong
Huawei Technologies
Huawei Building, No. 156 Beiqing Rd.
Beijing 100095
China
Email: jie.dong@huawei.com
Mach(Guoyi) Chen
Huawei Technologies
Huawei Building, No. 156 Beiqing Rd.
Beijing 100095
China
Email: mach.chen@huawei.com
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