Network Working Group J. Dong
Internet-Draft M. Chen
Intended status: Standards Track Huawei Technologies
Expires: July 28, 2014 H. Gredler
Juniper Networks, Inc.
S. Previdi
Cisco Systems, Inc.
January 24, 2014
Distribution of MPLS Traffic Engineering (TE) LSP State using BGP
draft-ietf-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
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 28, 2014.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Internet-Draft MPLS TE LSP State Distribution using BGP January 2014
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Carrying LSP State Information in BGP . . . . . . . . . . . . 4
2.1. LSP Identifier Information . . . . . . . . . . . . . . . 4
2.2. LSP State Information . . . . . . . . . . . . . . . . . . 5
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Normative References . . . . . . . . . . . . . . . . . . 7
5.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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].
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-----------
| ----- |
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 several 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
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 function.
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.
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2. Carrying LSP State Information in BGP
2.1. LSP Identifier Information
The TE LSP Identifier information is advertised in BGP UPDATE
messages using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes
[RFC4760]. The "Link State NLRI" defined in
[I-D.ietf-idr-ls-distribution] is extended to carry the TE LSP
Identifier information. BGP speakers that wish to exchange TE LSP
information MUST use the BGP Multiprotocol Extensions Capability Code
(1) to advertise the corresponding (AFI, SAFI) pair, as specified in
[RFC4760].
The format of "Link State NLRI" is defined in
[I-D.ietf-idr-ls-distribution]. Two new "NLRI Type" are defined for
TE LSP Identifier Information as following:
o NLRI Type = 5: IPv4 TE LSP NLRI
o NLRI-Type = 6: IPv6 TE LSP NLRI
The IPv4 TE LSP NLRI (NLRI Type = 5) is shown in the following
figure:
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
+-+-+-+-+-+-+-+-+
| Protocol-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier |
| (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Tunnel Sender Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel ID | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Tunnel End-point Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2. IPv4 TE LSP NLRI
The IPv6 TE LSP NLRI (NLRI Type = 6) is shown in the following
figure:
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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
+-+-+-+-+-+-+-+-+
| Protocol-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier |
| (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| IPv6 Tunnel Sender Address |
+ (16 octets) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel ID | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| IPv6 Tunnel End-point Address |
+ (16 octets) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3. IPv6 TE LSP NLRI
For IPv4 TE LSP NLRI and IPv6 TE LSP NLRI, the Protocol-ID field is
set to 6, which indicates that the NLRI information has been sourced
by RSVP-TE.
The Identifier field is used to discriminate between instances with
different LSP technology - e.g. one identifier can identify the
instance for packet path, and another one is to identify the instance
of optical path.
The other fields in the IPv4 TE LSP NLRI and IPv6 TE LSP NLRI are the
same as specified in [RFC3209].
2.2. LSP State Information
The LSP State TLV is used to describe the characteristics of the TE
LSPs, which is carried in the optional non-transitive BGP Attribute
"LINK_STATE Attribute" defined in [I-D.ietf-idr-ls-distribution].
The "Value" field of the LSP State TLV corresponds to the format and
semantics of a set of objects defined in [RFC3209], [RFC3473] and
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[RFC5440] for TE LSPs. Rather than replicating all RSVP-TE related
objects in this document the semantics and encodings of existing
RSVP-TE objects are re-used. Hence all RSVP-TE LSP objects are
regarded as sub-TLVs. The LSP State TLV SHOULD only be used with
IPv4/IPv6 TE LSP 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ TE LSP Objects (variable) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4. LSP State TLV
Currently the TE LSP Objects that can be carried in the LSP State TLV
include:
o LSP Attributes (LSPA) Object [RFC5440]
o Explicit Route Object (ERO) [RFC3209]
o Record Route Object (RRO) [RFC3209]
o BANDWIDTH Object [RFC5440]
o METRIC Object [RFC5440]
o Protection Object [RFC3473]
o Admin_Status Object [RFC3473]
Other TE LSP objects may also be carried in LSP state TLV, which is
for further study.
3. IANA Considerations
IANA needs to assign one new TLV type for "LSP State TLV" from the
TLV registry of Link_State Attribute.
IANA needs to assign one Protocol-ID for 'RSVP-TE' from the BGP-TE/LS
registry of Protocol-IDs.
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4. Security Considerations
Procedures and protocol extensions defined in this document do not
affect the BGP security model. See [RFC6952] for details.
5. References
5.1. Normative References
[I-D.ietf-idr-ls-distribution]
Gredler, H., Medved, J., Previdi, S., Farrel, A., and S.
Ray, "North-Bound Distribution of Link-State and TE
Information using BGP", draft-ietf-idr-ls-distribution-04
(work in progress), November 2013.
[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
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.
5.2. Informative References
[I-D.ietf-pce-stateful-pce]
Crabbe, E., Medved, J., Minei, I., and R. Varga, "PCEP
Extensions for Stateful PCE", draft-ietf-pce-stateful-
pce-07 (work in progress), October 2013.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006.
[RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, May 2013.
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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
Hannes Gredler
Juniper Networks, Inc.
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
US
Email: hannes@juniper.net
Stefano Previdi
Cisco Systems, Inc.
Via Del Serafico, 200
Rome 00142
Italy
Email: sprevidi@cisco.com
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