Network Working Group Fatai Zhang
Internet-Draft Dan Li
Intended status: Standards Track Huawei
O. Gonzalez de Dios
Telefonica Investigacion y Desarrollo
C. Margaria. C
Nokia Siemens Networks
Expires: April 30, 2012 October 31, 2011
RSVP-TE Extensions for Configuration SRLG of an FA
draft-zhang-ccamp-srlg-fa-configuration-04.txt
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with
the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 8, 2012.
Abstract
This memo provides extensions for the Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) for the support of the automatic
discovery of SRLG of an LSP.
Zhang Expires 2012 [Page 1]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
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. RSVP-TE Requirements......................................... 4
2.1. SRLG Collection Indication ............................. 4
2.2. SRLG Collection......................................... 4
2.3. SRLG Update ............................................ 4
3. RSVP-TE Extensions .......................................... 4
3.1. SRLG Collection Flag ................................... 4
3.2. SRLG sub-object ........................................ 5
4. Signaling Procedures ........................................ 6
4.1. SRLG Collection ........................................ 6
4.2. SRLG Update ............................................ 6
5. Manageability Considerations ................................ 7
5.1. Policy Configuration ................................... 7
5.2. Coherent SRLG IDs ...................................... 7
6. IANA Considerations ......................................... 7
6.1. RSVP Attribute Bit Flags ............................... 7
6.2. ROUTE_RECORD Object .................................... 8
7. Security Considerations ..................................... 8
8. References .................................................. 8
9. Authors' Addresses .......................................... 10
1. Introduction
As described in [RFC4206], H-LSP (Hierarchical LSP) can be used for
carrying one or more other LSPs. [RFC6107] further mentions the
implementation of H-LSP. In packet networks, e.g. MPLS networks, H-
LSP mechanism can be implemented by MPLS label stack. In non-packet
networks where the label is implicit, label stacks are not possible,
and H-LSPs rely on the ability to nest switching technologies. Thus,
for example, a lambda switch capable (LSC) LSP can carry a time
division multiplexing (TDM) LSP, but cannot carry another LSC LSP.
S-LSP (LSP Stitching), which is defined in [RFC5150], is an LSP that
represents a segment of another LSP, i.e., the S-LSP is viewed as
one hop by another LSP. As described in [RFC6107], in the data plane
the LSPs are stitched so that there is no label stacking or nesting.
Zhang Expires 2012 [Page 2]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
Thus, an S-LSP must be of the same switching technology as the end-
to-end LSP that it facilitates.
Therefore, H-LSP mechanism can be used in both multi-domain and
multi-layer scenarios and S-LSP mechanism can only be used in multi-
domain scenario.
Both of the H-LSP and S-LSP can be advertised as a TE link in a
GMPLS routing instance for path computation purpose. As described in
[RFC6107], if the LSP (H-LSP or S-LSP) is advertised in the same
instance of the control plane that advertises the TE links from
which the LSP is constructed, the LSP is called an FA.
In multi-domain or multi-layer context, the path information of an
LSP may not be provided to the ingress node for confidential reasons
and the ingress node may not run the same routing instance with the
intermediate nodes traversed by the path. In such scenarios, the
ingress node can not get the SRLG information of the path
information which the LSP traverse.
Even if the ingress node has the same routing instance with the
intermediate nodes traversed by the path, the path information of
the H-LSP or S-LSP may not be provided to the ingress node. Hence
the ingress node may also not know the SRLG of the path the LSP
traverses.
In the case that the ingress node does not get the SRLG of the path
the LSP traverses(i.e. H-LSP or S-LSP), there are disadvantages as
follows:
o SRLG-disjoint path, for instance in case of end-to-end path
protection, cannot be calculated
o Intermediate nodes of a pre-planned shared restoration LSP cannot
correctly decide on the SRLG-disjointness between two PPRO
(PRIMARY_PATH_ROUTE Object)
o In case that an LSP is advertised as a TE-Link, the ingress node
cannot provide the correct SRLG for the TE-Link automatically
In case that an LSP is advertised as a TE-Link, the SRLG information
of the TE link needs to be configured manually or automatically.
However, for manual configuration, there are some disadvantages
(e.g., require configuration coordination and additional management;
manual errors may be introduced) mentioned in Section 1.3.4 of
[RFC6107].
Zhang Expires 2012 [Page 3]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
In addition, Section 1.2 of [RFC6107] describes it is desirable to
have a kind of automatic mechanism to advertise the FA (i.e., to
signal an LSP and automatically coordinate its use and
advertisement in any of the ways with minimum involvement from an
operator).
Thus, in order to provide the SRLG information to the TE link
automatically when an LSP (H-LSP or S-LSP) is advertised as a TE
link, allow disjoint path calculation at ingress and allow correct
pre-planned shared LSP to correctly share resource, this document
provides an automatic mechanism to collect the SRLG used by a LSP
automatically.
2. RSVP-TE Requirements
2.1. SRLG Collection Indication
The head nodes of the LSP must be capable of indicating whether the
SRLG information of the LSP should be collected during the signaling
procedure of setting up an LSP.
2.2. SRLG Collection
The SRLG information can be collected during the setup of an LSP.
Then the endpoints of the LSP can get the SRLG information and use
it for routing, sharing and TE link configuration purposes.
2.3. SRLG Update
When the SRLG information changes, the endpoints of the LSP need to
be capable of updating the SRLG information of the path. It means
that the signaling should be capable of updating the newly SRLG
information to the endpoints.
3. RSVP-TE Extensions
3.1. SRLG Collection Flag
In order to indicate nodes that SRLG collection is desired, this
document defines a new flag in the Attribute Flags TLV, which is
carried in an LSP_REQUIRED_ATTRIBUTES Object:
o Bit Number (to be assigned by IANA, recommended bit zero): SRLG
Collection flag
The SRLG Collection flag is meaningful on a Path message. If the
SRLG Collection flag is set to 1, it means that the SRLG information
Zhang Expires 2012 [Page 4]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
should be reported to the head and tail node along the setup of the
LSP.
The rules of the processing of the Attribute Flags TLV are not
changed.
3.2. SRLG sub-object
This document defines a new RRO sub-object (ROUTE_RECORD sub-object)
to record the SRLG information of the LSP. Its format is modeled on
the RRO sub-objects defined in [RFC3209].
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 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRLG ID 1 (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ...... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRLG ID n (4 bytes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
The type of the sub-object, to be assigned by IANA, which
is recommended 34.
Length
The Length contains the total length of the sub-object in
bytes, including the Type and Length fields. The Length
depends on the number of SRLG IDs.
SRLG Id
The 32-bit identifier of the SRLG.
Reserved
This field is reserved. It SHOULD be set to zero on
transmission and MUST be ignored on receipt.
The rules of the processing of the LSP_REQUIRED_ATTRIBUTES Object
and ROUTE_RECORD Object are not changed.
Zhang Expires 2012 [Page 5]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
4. Signaling Procedures
4.1. SRLG Collection
Typically, the head node gets the route information of an LSP by
adding a RRO which contains the sender's IP addresses in the Path
message. If a head node also desires SRLG recording, it sets the
SRLG Collection Flag in the Attribute Flags TLV which can be carried
in an LSP_REQUIRED_ATTRIBUTES Object.
When a node receives a Path message which carries an
LSP_REQUIRED_ATTRIBUTES Object and the SRLG Collection Flag is set,
if local policy determines that the SRLG information should not be
provided to the endpoints, it must return a PathErr message to
reject the Path message. Otherwise, it must add an SRLG sub-object
to the RRO to carry the local SRLG information. Then it forwards the
Path message to the next node in the downstream direction.
Following the steps described above, the intermediate nodes of the
LSP can collect the SRLG information in the RRO during the
forwarding of the Path message hop by hop. When the Path message
arrives at the tail node, the tail node can get the SRLG information
from the RRO.
Before the Resv message is sent to the upstream node, the tail node
adds an SRLG sub-object to the RRO. The collected SRLG information
can be carried in the SRLG sub-object. Therefore, during the
forwarding of the Resv message in the upstream direction, the SRLG
information is not needed to be collected hop by hop.
Based on the above procedure, the endpoints can get the SRLG
information automatically. Then the endpoints can for instance
advertise it as a TE link to the routing instance based on the
procedure described in [RFC6107] and configure the SRLG information
of the FA automatically.
It is noted that a node (e.g. the edge node of a domain) may edit
the RRO to remove the route information (e.g. node, interface
identifier information) before forwarding it due to some reasons
(e.g. confidentiality or reduce the size of RRO), but the SRLG
information should be retained if it is desirable for the endpoints
of the LSP.
4.2. SRLG Update
When the SRLG information of a link is changed, the LSPs using that
link should be aware of the changes. The procedures defined in
Zhang Expires 2012 [Page 6]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
Section 4.4.3 of [RFC 3209] MUST be used to refresh the SRLG
information.
5. Manageability Considerations
5.1. Policy Configuration
In a border node of inter-domain or inter-layer network, the
following SRLG processing policy should be capable of being
configured:
o Whether the SRLG IDs of the domain or specific layer network can
be exposed to the nodes outside the domain or layer network.
o If the SRLG IDs must not be exposed to the nodes outside of the
domain or specific layer network by policy, the border node must
reject the Path message desiring SRLG recording and send a PathErr
message with the defined error code ''Policy Control Failure''/''Inter-
domain policy failure''.
5.2. Coherent SRLG IDs
In a multi-layer multi-domain scenario, SRLG ids may be configured
by different management entities in each layer/domain. In such
scenarios, maintaining a coherent set of SRLG IDs is a key
requirement in order to be able to use the SRLG information properly.
Thus, SRLG IDs must be unique. Note that current procedure is
targeted towards a scenario where the different layers and domains
belong to the same operator, or to several coordinated
administrative groups.
Further scenarios, where coherence in the SRLG IDs cannot be
guaranteed are out of the scope of the present document and are left
for further study.
6. IANA Considerations
6.1. RSVP Attribute Bit Flags
The IANA has created a registry and manages the space of attributes
bit flags of Attribute Flags TLV as described in section 11.3 of
[RFC5420]. It is requested that the IANA makes assignments from the
Attribute Bit Flags.
This document introduces a new Attribute Bit Flag:
- Bit number: TBD (0)
Zhang Expires 2012 [Page 7]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
- Defining RFC: this I-D
- Name of bit: SRLG Collection Flag
- The meaning of the Attribute Flags TLV on a Path is defined in
this I-D
6.2. ROUTE_RECORD Object
IANA has made the following assignments in the "Class Names, Class
Numbers, and Class Types" section of the "RSVP PARAMETERS" registry
located at http://www.iana.org/assignments/rsvp-parameters. We
request that IANA make assignments from the ROUTE_RECORD [RFC3209]
portions of this registry.
This document introduces a new RRO sub-object:
Type Name Reference
--------- ---------------------- ---------
TBD (34) SRLG sub-object This I-D
7. Security Considerations
TBD.
8. Acknowledgements
The authors would like to thank Igor Bryskin and Ramon Casellas for
their useful comments to the document.
9. References
[RFC2119] S. Bradner, "Key words for use in RFCs to indicate
requirements levels", RFC 2119, March 1997.
[RFC3209] D. Awduche, L. Berger, D. Gan, T. Li, V. Srinivasan and G.
Swallow, " RSVP-TE: Extensions to RSVP for LSP Tunnels",
RFC 3209, December 2001.
Zhang Expires 2012 [Page 8]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
[RFC3477] K. Kompella, Y. Rekhter, "Signalling Unnumbered Links in
Resource ReSerVation Protocol - Traffic Engineering (RSVP-
TE)", rfc3477, January 2003.
[RFC4206] K. Kompella, Y. Rekhter, "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label Switching
(GMPLS) Traffic Engineering (TE)", RFC 4206, October 2005.
[RFC4208] G. Swallow, J. Drake, Boeing, H. Ishimatsu, and Y.
Rekhter, "Generalized Multiprotocol Label Switching
(GMPLS) User-Network Interface (UNI): Resource ReserVation
Protocol-Traffic Engineering (RSVP-TE) Support for the
Overlay Model", RFC 4208, October 2005.
[RFC4874] CY. Lee, A. Farrel, S. De Cnodder, " Exclude Routes -
Extension to Resource ReserVation Protocol-Traffic
Engineering (RSVP-TE) ", RFC 4874, April 2007.
[RFC5150] Ayyangar, A., Vasseur, J.P, and Farrel, A., "Label
Switched Path Stitching with Generalized Multiprotocol
Label Switching Traffic Engineering (GMPLS TE)", RFC 5150,
February 2008.
[RFC5420] A. Farrel, D. Papadimitriou, J.P, and A. Ayyangar,
"Encoding of Attributes for MPLS LSP Establishment Using
Resource Reservation Protocol Traffic Engineering (RSVP-
TE)", RFC 5420, February 2009.
[RFC6107] K. Shiomoto, A. Farrel, " Procedures for Dynamically
Signaled Hierarchical Label Switched Paths ", RFC 6107,
February 2011.
Zhang Expires 2012 [Page 9]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
10. Authors' Addresses
Fatai Zhang
Huawei Technologies
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28972912
Email: zhangfatai@huawei.com
Dan Li
Huawei Technologies
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28970230
Email: danli@huawei.com
Oscar Gonzalez de Dios
Telefonica Investigacion y Desarrollo
Emilio Vargas 6
Madrid, 28045
Spain
Phone: +34 913374013
Email: ogondio@tid.es
Cyril Margaria
Nokia Siemens Networks
St Martin Strasse 76
Munich, 81541
Germany
Phone: +49 89 5159 16934
Email: cyril.margaria@nsn.com
Xiaobing Zi
Huawei Technologies
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Zhang Expires 2012 [Page 10]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
Phone: +86-755-28973229
Email: zixiaobing@huawei.com
Intellectual Property
The IETF Trust takes no position regarding the validity or scope of
any Intellectual Property Rights or other rights that might be
claimed to pertain to the implementation or use of the technology
described in any IETF Document or the extent to which any license
under such rights might or might not be available; nor does it
represent that it has made any independent effort to identify any
such rights.
Copies of Intellectual Property disclosures made to the IETF
Secretariat and any assurances of licenses to be made available, or
the result of an attempt made to obtain a general license or
permission for the use of such proprietary rights by implementers or
users of this specification can be obtained from the IETF on-line
IPR repository at http://www.ietf.org/ipr
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
any standard or specification contained in an IETF Document. Please
address the information to the IETF at ietf-ipr@ietf.org.
The definitive version of an IETF Document is that published by, or
under the auspices of, the IETF. Versions of IETF Documents that are
published by third parties, including those that are translated into
other languages, should not be considered to be definitive versions
of IETF Documents. The definitive version of these Legal Provisions
is that published by, or under the auspices of, the IETF. Versions
of these Legal Provisions that are published by third parties,
including those that are translated into other languages, should
not be considered to be definitive versions of these Legal
Provisions.
For the avoidance of doubt, each Contributor to the IETF Standards
Process licenses each Contribution that he or she makes as part of
the IETF Standards Process to the IETF Trust pursuant to the
provisions of RFC 5378. No language to the contrary, or terms,
conditions or rights that differ from or are inconsistent with the
Zhang Expires 2012 [Page 11]
draft-zhang-ccamp-srlg-fa-configuration-04.txt October 2011
rights and licenses granted under RFC 5378, shall have any effect
and shall be null and void, whether published or posted by such
Contributor, or included with or in such Contribution.
Disclaimer of Validity
All IETF Documents and the information contained therein are
provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION
HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET
SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE
DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION THEREIN
WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Full Copyright Statement
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
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.
Zhang Expires 2012 [Page 12]