Network Working Group M. Chen
Internet-Draft Huawei
Intended status: Standards Track G. Mirsky
Expires: April 16, 2015 Ericsson
October 13, 2014
Extensions to OSPF for Source Identifier Distribution
draft-chen-ospf-source-identifier-distribution-00
Abstract
A Source Identifier (SI) is carried in an MPLS Source Label and used
to identify (one of) the ingress LSR(s) to a specific LSP. This
document defines extensions to OSPF protocol for distribution of the
correlation of a SI to an specific LSR. Therefore, the egress and
intermediate LSRs can determine from which LSR an MPLS packet is
sent.
This document also defines OSPF extensions to advertise the Source
Label Capability (SLC) of each LSR that indicates whether an LSR can
properly process the Source Label Indicator (SLI) special purpose
label and Source Label (SL). With the SLC, an ingress LSR can
determine whether it is allowed to insert a SL 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
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 16, 2015.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Extensions to OSPF . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
As defined in [I-D.chen-mpls-source-label], a Source Identifier (SI)
is a number in the range of [16, 65535]. Each node in a domain will
be allocated one or more unique SIs. A SI is carried in an
MultiProtocol Label Switching (MPLS) Source Label (SL) and used to
identify (one of) the ingress Label Switching Router (LSR) to a
specific Label Switched Path (LSP).
To identify from where an MPLS packet is sent, the egress/
intermediate LSRs need to know to which ingress LSR a SI is
correlated. Therefore, a mechanism to distribute the correlation of
a SI to its correlated LSR is required.
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 SLI and SL, otherwise the packet will be
dropped at the egress LSR. The capability is called Source Label
Capability (SLC).
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This document defines extensions to OSPF protocol to distribute SI to
LSR mapping and advertise the SLC of each LSR.
2. Extensions to OSPF
The Source Identifier TLV is defined to distribute the SI(s) to
ingress LSR mapping information and the SLC. No sub-TLV is currently
defined for the Source Identifier TLV.
The Source Identifier TLV is advertised in an OSPF Router Information
(RI) [RFC4790] Link State Advertisement (LSA), 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Source Identifier 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Source Identifier n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 - OSPF Source Identifier TLV format
The value of "Type" field is TBD1.
The "Length" field defines the length of the Reserved and Source
Identifier fields in octets, which excludes the Router ID field.
Each "Source Identifier" field (20 bits) contains a SI that
identifies the advertising LSR.
The "Reserved" field MUST be set to zero when sending and MUST be
ignored when received.
3. Elements of Procedure
The Source Identifier TLV is carried in the OSPF Router Information
(RI) LSA that is defined in [RFC4790]. All the procedures that
defined in [RFC4790] are inherited here.
The flooding scope of the Source Identifier TLV can be either area
local or entire OSPF domain. The flooding scope is controlled by the
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Opaque LSA type in OSPFv2 [RFC2370] and by the S1 and S2 bits in
OSPFv3 [RFC2740]. If the flooding scope is area local, the Source
Identifier TLV MUST be carried within an OSPFv2 Type 10 RI LSA or
within an OSPFv3 RI LSA with the S1 bit set and the S2 bit clear. If
the flooding scope is the entire IGP domain, the Source Identifier
TLV MUST be carried within an OSPFv2 Type 11 RI LSA or within an
OSPFv3 RI LSA with the S1 bit clear and the S2 bit set.
The Source Identifier TLV is an optional TLV. Upon receipt the TLV,
a router will silently ignore the TLV as defined in [RFC4790] if it
does not support it. If Source Identifier TLV is not present that
MUST be interpreted as signaling of non-support of SLC by the LSR.
Presence of a Source Identifier TLV MUST be interpreted as support of
SLC by the LSR. A Source Identifier TLV MUST appear only one time in
an LSA. When received, only first Source Identifier TLV is valid,
subsequent Source Identifier TLVs MUST be ignored.
4. IANA Considerations
IANA is requested to assign a new TLV code point for the Source
Identifier TLV carried within the Router Information LSA.
Type Value TLV Name Reference
---------- ------------------ --------------
TBD1 Source Identifier (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.
[RFC2370] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, July
1998.
[RFC2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", RFC
2740, December 1999.
[RFC4790] Newman, C., Duerst, M., and A. Gulbrandsen, "Internet
Application Protocol Collation Registry", RFC 4790, March
2007.
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7.2. Informative References
[I-D.chen-mpls-source-label]
Chen, M., Xu, X., Li, Z., Fang, L., and G. Mirsky,
"MultiProtocol Label Switching (MPLS) Source Label",
draft-chen-mpls-source-label-05 (work in progress), July
2014.
Authors' Addresses
Mach(Guoyi) Chen
Huawei
Email: mach.chen@huawei.com
Greg Mirsky
Ericsson
Email: Gregory.mirsky@ericsson.com
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