Internet DRAFT - draft-chen-isis-source-label-distribution
draft-chen-isis-source-label-distribution
Network Working Group M. Chen
Internet-Draft Huawei
Intended status: Standards Track G. Mirsky
Expires: August 17, 2014 Ericsson
February 13, 2014
Extensions to ISIS for Source Label Distribution
draft-chen-isis-source-label-distribution-00
Abstract
An MPLS Source Label (SL) is defined to identify a node that is (one
of) the ingress LSRs to a specific LSP. This document defines
extensions to ISIS protocol for distribution of the mapping of an
MPLS Source Label to an specific LSR. Therefore, the egress and
intermediate LSRs can determine from which LSR an MPLS packet is
sent.
This document also defines ISIS extensions to advertise the Source
Label Capability (SLC) of each LSR that indicates whether an LSR can
process the Source Label. With the SLC, an ingress LSR can determine
whether it is allowed to insert a Source Label into the label stack
for a specific LSP.
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 17, 2014.
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Copyright Notice
Copyright (c) 2014 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Extensions to ISIS . . . . . . . . . . . . . . . . . . . . . 3
3. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
The MPLS Source Label is defined in [I-D.chen-mpls-source-label], it
is used to identify (one of) the ingress LSR(s) of an LSP. To
identify from where an MPLS packet is sent, a pure Source Label (SL)
is not enough, it needs to know to which LSR a SL is correlated.
Therefore, there needs a mechanism to distribute the mapping
information between a SL and its correlated LSR.
In addition, for an ingress LSR, before inserting a SL in the label
stack of an LSP, it needs to know whether the egress LSR has the
capability to process the SL, otherwise the packet will be dropped at
the egress LSR. The capability is called Source Label Capability
(SLC).
This document defines extensions to ISIS [RFC1195] protocol to
distribute SL to LSR mapping and advertise the SLC of each LSR.
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2. Extensions to ISIS
The Source Label sub-TLV is used to distribute the Source Label to
LSR mapping and the SLC. The Source Label sub-TLV is advertised
within an IS-IS CAPABILITY TLV that is defined in [RFC4971], it has
the following format:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| System ID(cond.) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Source Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 - ISIS Source Label sub-TLV format
The value of Type field is TBD1.
The Length field defines the length of the Reserved and Source Label
in octets, the value is 4.
The Source Label field contains the Source Label that identifies the
advertising LSR.
3. Elements of Procedure
The Source Label sub-TLV is carried within an IS-IS CAPABILITY TLV
defined in [RFC4971]. All the procedures that defined in [RFC4971]
are inherited here.
The flooding scope of the Source Label sub-TLV can be either area
local or entire IGP domain. The flooding scope is controlled by the
S flag in the IS-IS Router Capability TLV [RFC4971]. If the flooding
scope is area local, the Source Label sub-TLV MUST be carried within
an IS-IS Router Capability TLV with the S flag clear. If the
flooding scope is the entire IGP domain, the Source Label sub-TLV
MUST be carried within an IS-IS Router Capability TLV with the S flag
set.
The Source Label sub-TLV is an optional sub-TLV. Upon receipt the
sub-TLV, a router will silently ignore the sub-TLV as defined in
[RFC4971] if it does not support it. If Source Label sub-TLV is not
present that MUST be interpreted as signaling of non-support of SLC
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by the LSR. Presence of a Source Label sub-TLV MUST be interpreted
as support of SLC by the LSR. A Source Label sub-TLV MUST appear
only one time in an LSP.
4. IANA Considerations
IANA is requested to assign a new sub-TLV code point for the Source
Label sub-TLV carried within the IS-IS Router Capability TLV.
Type Value TLV Name Reference
---------- --------------- --------------
TBD1 Source Label (this document)
5. Security Considerations
TBD.
6. Acknowledgements
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.
[RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
System to Intermediate System (IS-IS) Extensions for
Advertising Router Information", RFC 4971, July 2007.
7.2. Informative References
[I-D.chen-mpls-source-label]
Chen, M., Building, K., Li, Z., and L. Fang,
"MultiProtocol Label Switching (MPLS) Source Label",
draft-chen-mpls-source-label-01 (work in progress),
October 2013.
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, December 1990.
Authors' Addresses
Mach(Guoyi) Chen
Huawei
Email: mach.chen@huawei.com
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Greg Mirsky
Ericsson
Email: Gregory.mirsky@ericsson.com
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