Network Working Group J. Dong
Internet-Draft M. Chen
Intended status: Standards Track Huawei Technologies
Expires: November 8, 2015 H. Gredler
Juniper Networks, Inc.
S. Previdi
Cisco Systems, Inc.
J. Tantsura
Ericsson
May 7, 2015
Distribution of MPLS Traffic Engineering (TE) LSP State using BGP
draft-ietf-idr-te-lsp-distribution-03
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
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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 November 8, 2015.
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Copyright Notice
Copyright (c) 2015 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
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
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
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 . . . . . . . . . . . . . . . . . . 6
3. Operational Considerations . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
4.1. BGP-LS NLRI-Types . . . . . . . . . . . . . . . . . . . . 8
4.2. BGP-LS Protocol-IDs . . . . . . . . . . . . . . . . . . . 8
4.3. BGP-LS Instance-IDs . . . . . . . . . . . . . . . . . . . 9
4.4. BGP-LS Attribute TLVs . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References . . . . . . . . . . . . . . . . . . 9
7.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
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,
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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 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 multi-area or multi-AS scenarios, each area or AS can have a child
PCE to collect the LSP states of its own domain, in addition a parent
PCE needs to collect the LSP information from multiple child PCEs to
obtain a global view of LSPs inside and across the domains involved.
In another network scenario, 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.
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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 to some external components
[I-D.ietf-idr-ls-distribution]. Using the same protocol to collect
other network layer information would be desirable for 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 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:
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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) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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:
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
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For IPv4 and IPv6 TE LSP NLRI, the Protocol-ID field specifies the
type of signaling of the TE LSP. The following Protocol-IDs applies
to IPv4/IPv6 TE LSP NLRI:
+-------------+----------------------------------+
| Protocol-ID | NLRI information source protocol |
+-------------+----------------------------------+
| TBD | RSVP-TE |
| TBD | Segment Routing |
+-------------+----------------------------------+
The 64-Bit 'Identifier' field is used to discriminate between
instances with different LSP technologies. The default identifier
"0" identifies the instance for packet switched LSPs. A new
identifier TBD is used to identify the instance of optical layer
LSPs.
The other fields in the IPv4 TE LSP NLRI and IPv6 TE LSP NLRI are the
same as defined in [RFC3209]. When the Protocol-ID is set to Segment
Routing, the Tunnel ID and LSP ID field SHOULD be filled with the
source node's locally generated identifiers which can uniquely
identify a specific SR LSP.
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
other extensions for TE LSPs. Rather than replicating all RSVP-TE
related objects in this document, the semantics and encodings of the
existing TE LSP objects are re-used. Hence all 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
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Currently the TE LSP Objects that can be carried in the LSP State TLV
include:
o SENDER_TSPEC and FLOW_SPEC [RFC2205]
o SESSION_ATTRIBUTE [RFC3209]
o Explicit Route Object (ERO) [RFC3209]
o Record Route Object (RRO) [RFC3209]
o FAST_REROUTE Object [RFC4090]
o DETOUR Object [RFC4090]
o EXCLUDE_ROUTE Object (XRO) [RFC4874]
o SECONDARY_EXPLICIT_ROUTE Object (SERO) [RFC4873]
o SECONDARY_RECORD_ROUTE (SRRO) [RFC4873]
o LSP_ATTRIBUTES Object [RFC5420]
o LSP_REQUIRED_ATTRIBUTES Object [RFC5420]
o PROTECTION Object [RFC3473][RFC4872][RFC4873]
o ASSOCIATION Object [RFC4872]
o PRIMARY_PATH_ROUTE Object [RFC4872]
o ADMIN_STATUS Object [RFC3473]
o BANDWIDTH Object [RFC5440]
o METRIC Object [RFC5440]
For the TE LSP Objects listed above, the corresponding subobjects are
also applicable to this mechanism. Other TE LSP objects which
reflect specific states or attributes of the LSP may also be carried
in the LSP state TLV, which is for further study.
3. Operational Considerations
The Existing BGP operational procedures apply to this document. No
new operation procedures are defined in this document. The
operational considerations as specified in
[I-D.ietf-idr-ls-distribution] apply to this document.
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In general the ingress nodes of the LSPs are responsible for the
distribution of LSP state information, while other nodes on the LSP
path may report the LSP information if needed, e.g. the border
routers in the inter-domain case, where the ingress node may not have
the complete information of the end-to-end path.
4. IANA Considerations
IANA is requested to administer the assignment of new values defined
in this document and summarized in this section.
IANA needs to assign one new TLV type for "LSP State TLV" from the
registry of BGP-LS Attribute TLVs.
4.1. BGP-LS NLRI-Types
IANA maintains a registry called "Border Gateway Protocol - Link
State (BGP-LS) Parameters" with a sub-registry called "BGP-LS NLRI-
Types".
IANA is requested to assign two new NLRI-Types:
+------+---------------------------+---------------+
| Type | NLRI Type | Reference |
+------+---------------------------+---------------+
| 5 | IPv4 TE LSP NLRI | this document |
| 6 | IPv6 TE LSP NLRI | this document |
+------+---------------------------+---------------+
4.2. BGP-LS Protocol-IDs
IANA maintains a registry called "Border Gateway Protocol - Link
State (BGP-LS) Parameters" with a sub-registry called "BGP-LS
Protocol-IDs".
IANA is requested to assign two new Protocol-IDs:
+-------------+----------------------------------+---------------+
| Protocol-ID | NLRI information source protocol | Reference |
+-------------+----------------------------------+---------------+
| TBD | RSVP-TE | this document |
| TBD | Segment Routing | this document |
+-------------+----------------------------------+---------------+
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4.3. BGP-LS Instance-IDs
IANA maintains a registry called "Border Gateway Protocol - Link
State (BGP-LS) Parameters" with a sub-registry called "BGP-LS Well-
known Instance-IDs".
IANA is requested to assign one new Instance-ID:
+------------+----------------------------------+---------------+
| Identifier | Routing Universe | Reference: |
+------------+----------------------------------+---------------+
| TBD | Default Optical Network Topology | this document |
+------------+----------------------------------+---------------+
4.4. BGP-LS Attribute TLVs
IANA maintains a registry called "Border Gateway Protocol - Link
State (BGP-LS) Parameters" with a sub-registry called "Node Anchor,
Link Descriptor and Link Attribute TLVs".
IANA is requested to assign one new TLV code point:
+-----------+---------------------+---------------+-----------------+
| TLV Code | Description | IS-IS TLV/ | Value defined |
| Point | | Sub-TLV | in: |
+-----------+---------------------+---------------+-----------------+
| TBD | LSP State TLV | --- | this document |
+-----------+---------------------+---------------+-----------------+
5. Security Considerations
Procedures and protocol extensions defined in this document do not
affect the BGP security model. See [RFC6952] for details.
6. Acknowledgements
The authors would like to thank Dhruv Dhody and Mohammed Abdul Aziz
Khalid for their review and valuable comments.
7. References
7.1. 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-10
(work in progress), January 2015.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 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.
[RFC4090] Pan, P., Swallow, G., and A. Atlas, "Fast Reroute
Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May
2005.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760, January
2007.
[RFC4872] Lang, J., Rekhter, Y., and D. Papadimitriou, "RSVP-TE
Extensions in Support of End-to-End Generalized Multi-
Protocol Label Switching (GMPLS) Recovery", RFC 4872, May
2007.
[RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
"GMPLS Segment Recovery", RFC 4873, May 2007.
[RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes -
Extension to Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE)", RFC 4874, April 2007.
[RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A.
Ayyangarps, "Encoding of Attributes for MPLS LSP
Establishment Using Resource Reservation Protocol Traffic
Engineering (RSVP-TE)", RFC 5420, February 2009.
[RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element
(PCE) Communication Protocol (PCEP)", RFC 5440, March
2009.
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7.2. Informative References
[I-D.ietf-pce-stateful-pce]
Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP
Extensions for Stateful PCE", draft-ietf-pce-stateful-
pce-11 (work in progress), April 2015.
[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.
Authors' Addresses
Jie Dong
Huawei Technologies
Huawei Campus, No. 156 Beiqing Rd.
Beijing 100095
China
Email: jie.dong@huawei.com
Mach(Guoyi) Chen
Huawei Technologies
Huawei Campus, 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
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Stefano Previdi
Cisco Systems, Inc.
Via Del Serafico, 200
Rome 00142
Italy
Email: sprevidi@cisco.com
Jeff Tantsura
Ericsson
300 Holger Way
San Jose, CA 95134
US
Email: jeff.tantsura@ericsson.com
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