CCAMP C. Margaria, Ed.
Internet-Draft Nokia Siemens Networks
Intended status: Standards Track G. Martinelli
Expires: August 28, 2013 Cisco
S. Balls
B. Wright
Metaswitch
February 24, 2013
LSP Attribute in ERO
draft-ietf-ccamp-lsp-attribute-ro-01
Abstract
LSP attributes can be specified or recorded for whole path, but they
cannot be targeted to a specific hop. This document proposes
alternative ways to extend the semantic for RSVP ERO object to target
LSP attributes to a specific hop.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Contributing Authors . . . . . . . . . . . . . . . . . . . 3
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. ERO LSP Attribute Subobject . . . . . . . . . . . . . . . . . 5
3.1. ERO LSP_ATTRIBUTE subobject . . . . . . . . . . . . . . . 5
3.2. Procedures . . . . . . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
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1. Introduction
Generalized MPLS (GMPLS) Traffic Engineering (TE) Label Switched
Paths (LSPs) can be route-constrained by making use of the Explicit
Route (ERO) object and related sub-objects as defined in [RFC3209],
[RFC3473], [RFC3477], [RFC4873], [RFC4874], [RFC5520] and [RFC5553].
Those route constraints are extended by a number of documents,
including element defined in [RFC6163],
[I-D.ietf-ccamp-wson-signaling],
[I-D.dong-ccamp-rsvp-te-mpls-tp-li-lb] or
[I-D.ali-ccamp-rc-objective-function-metric-bound].
RSVP already supports generic extension of LSP attributes in
[RFC5420]. In order to support current and future ERO constraint
extensions this document defines a mechanism to target LSP attributes
at a specific hop.
1.1. Contributing Authors
1.2. 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].
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2. Requirements
The requirement is to provide a generic mechanism to carry
information related to specific nodes when signaling an LSP. This
document does not restrict what that information can be used for.
LSP attribute defined [RFC5420] should be expressed in ERO and SERO
objects.
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3. ERO LSP Attribute Subobject
The ERO LSP Attributes subobject may be carried in the ERO or SERO
object if they are present. The subobject uses the standard format
of an ERO subobject.
3.1. ERO LSP_ATTRIBUTE subobject
The length is variable and content MUST be the same as for the
LSP_ATTRIBUTE object with Attributes TLVs. The size of the ERO sub-
object limits the size of the LSP Attribute TLV to 250 bytes. The
typical size of currently defined and forthcoming LSP_ATTRIBUTE TLVs
applicable to a specific hop (WSON_SIGNALING, OF and Metric) is not
foreseen to exceed this limit.
The ERO LSP attribute subobject is defined as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Type | Length | Reserved |R|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Attributes TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
See [RFC3209] for a description of L parameters. The attributes TLV
are encoded as defined in [RFC5420] section 3.
Type x TBD by IANA.
Length The Length contains the total length of the subobject in
bytes, including the Type and Length fields. The Length MUST be
always divisible by 4.
Reserved Reserved, must be set to 0 when the subobject is inserted
in the ERO, MUST NOT be changed when a node process the ERO and
must be ignored on the node addressed by the preceding ERO
subobjects.
R This bit reflects the LSP_REQUIRED_ATTRIBUTE and LSP_ATTRIBUTE
semantic. When set indicates required LSP attributes to be
processed by the node, when cleared the LSP attributes are not
required as described in Section 3.2.
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Attributes TLVs as defined in [RFC5420] section 3.
3.2. Procedures
As described in [RFC3209] and [RFC3473] the ERO is managed as a list
where each hop information starts with a subobject identifying an
abstract node or link. The LSP attribute subobject must be appended
after the existing subobjects defined in [RFC3209], [RFC3473],
[RFC3477], [RFC4873], [RFC4874], [RFC5520] and [RFC5553]. Several
LSP attribute subobject MAY be present, for each hop.
If a node is processing an LSP attribute subobject and does not
support handling of the subobject it will behave as described in
[RFC3209] when an unrecognized ERO subobject is encountered. This
node will return a PathErr with error code "Routing Error" and error
value "Bad EXPLICIT_ROUTE object" with the EXPLICIT_ROUTE object
included, truncated (on the left) to the offending unrecognized
subobject.
When the R bit is set a node MUST examine the attribute TLV present
in the subobject following the rules described in [RFC5420] section
5.2. When the R bit is not set a node MUST examine the attribute TLV
present in the subobject following the rules described in [RFC5420]
section 4.2.
A node processing an LSP attribute subobject with an LSP_ATTRIBUTE
TLV longer than the ERO subobject SHOULD return a PathErr with error
code "Routing Error" and error value "Bad EXPLICIT_ROUTE object" with
the EXPLICIT_ROUTE object included, truncated (on the left) to the
offending malformed subobject. The processing of the LSP_ATTRIBUTE
TLVs should be described in the documents defining them.
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4. IANA Considerations
TBD once a final approach has been chosen.
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5. Security Considerations
None.
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6. Acknowledgments
The authors would like to thanks Lou Berger for his directions and
Attila Takacs for inspiring this
[I-D.kern-ccamp-rsvpte-hop-attributes]. The authors also thanks Dirk
Schroetter for his contribution to the initial versions of the
documents (version -00 up to -02).
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7. References
7.1. 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
Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.
[RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
in Resource ReSerVation Protocol - Traffic Engineering
(RSVP-TE)", RFC 3477, January 2003.
[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.
[RFC5520] Bradford, R., Vasseur, JP., and A. Farrel, "Preserving
Topology Confidentiality in Inter-Domain Path Computation
Using a Path-Key-Based Mechanism", RFC 5520, April 2009.
[RFC5553] Farrel, A., Bradford, R., and JP. Vasseur, "Resource
Reservation Protocol (RSVP) Extensions for Path Key
Support", RFC 5553, May 2009.
7.2. Informative References
[I-D.ali-ccamp-rc-objective-function-metric-bound]
Ali, Z., Swallow, G., Filsfils, C., Fang, L., Kumaki, K.,
and R. Kunze, "Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) extension for signaling Objective
Function and Metric Bound",
draft-ali-ccamp-rc-objective-function-metric-bound-02
(work in progress), July 2012.
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[I-D.dong-ccamp-rsvp-te-mpls-tp-li-lb]
Dong, J., Chen, M., and Z. Li, "GMPLS RSVP-TE Extensions
for Lock Instruct and Loopback",
draft-dong-ccamp-rsvp-te-mpls-tp-li-lb-05 (work in
progress), December 2012.
[I-D.ietf-ccamp-wson-signaling]
Bernstein, G., Xu, S., Lee, Y., Martinelli, G., and H.
Harai, "Signaling Extensions for Wavelength Switched
Optical Networks", draft-ietf-ccamp-wson-signaling-05
(work in progress), February 2013.
[I-D.kern-ccamp-rsvpte-hop-attributes]
Kern, A. and A. Takacs, "Encoding of Attributes of LSP
intermediate hops using RSVP-TE",
draft-kern-ccamp-rsvpte-hop-attributes-00 (work in
progress), October 2009.
[RFC6163] Lee, Y., Bernstein, G., and W. Imajuku, "Framework for
GMPLS and Path Computation Element (PCE) Control of
Wavelength Switched Optical Networks (WSONs)", RFC 6163,
April 2011.
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Authors' Addresses
Cyril Margaria (editor)
Nokia Siemens Networks
St Martin Strasse 76
Munich, 81541
Germany
Phone: +49 89 5159 16934
Email: cyril.margaria@nsn.com
Giovanni Martinelli
Cisco
via Philips 12
Monza 20900
IT
Phone: +39 039 209 2044
Email: giomarti@cisco.com
Steve Balls
Metaswitch
100 Church Street
Enfield EN2 6BQ
UJ
Phone: +44 208 366 1177
Email: steve.balls@metaswitch.com
Ben Wright
Metaswitch
100 Church Street
Enfield EN2 6BQ
UJ
Phone: +44 208 366 1177
Email: Ben.Wright@metaswitch.com
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