Network Working Group Rahul Aggarwal
Internet Draft Kireeti Kompella
Expiration Date: March 2004 Juniper Networks
Advertising a Router's Local Addresses in OSPF TE Extensions
draft-raggarwa-ospf-te-node-addr-00.txt
1. Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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2. Abstract
This document describes procedures that enhance OSPF Traffic
Engineering (TE) extensions for advertising a router's local
addresses. This is needed to enable other routers in a network to
compute traffic engineered MPLS LSPs to a given router's local
addresses. Currently, the only addresses belonging to a router that
are advertised in TE LSAs are the router's local addresses on links
enabled for TE, and the Router ID.
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3. Motivation
In some cases it is desirable to setup, constrained shortest path
first (CSPF) computed MPLS TE LSPs, to local addresses of a router
that are not currently advertised in the TE LSAs i.e. loopback and
non-TE interface addresses.
For instance in a network carrying VPN and non-VPN traffic, its often
desirable to use different MPLS TE LSPs for the VPN traffic and the
non-VPN traffic. In this case one loopback address may be used as the
BGP next-hop for VPN traffic while another may be used as the BGP
next-hop for non-VPN traffic. Its also possible that different BGP
sessions are used for VPN and non-VPN services. Hence two separate
MPLS TE LSPs are desirable, one to each loopback address.
However currently routers in an OSPF network can only use CSPF to
compute MPLS TE LSPs to the router ID or the local addresses of TE
enabled links, of a remote router. This restriction arises because
OSPF TE extensions [OSPF-TE, OSPFv3-TE] only advertise the router ID
and the local addresses of TE enabled links, of a given router. Other
routers in the network can populate their traffic engineering
database (TED) with these local addresses belonging to the
advertising router. However they cannot populate the TED with other
local addresses of the advertising router i.e. loopback and non-TE
interface addresses. OSPFv2 stub links in the router LSA [OSPFv2],
provide stub reachability information to the router but are not
sufficient to learn all the local addresses of a router. The same
problem exists with intra-prefix LSAs in OSPFv3 [OSPFv3].
For the above reasons this document proposes an enhancement to OSPF
TE extensions to advertise the local addresses of a node.
4. A Potential Solution
A potential solution would be to advertise a TE link TLV for each
local address, possibly with a new link type. However, this is
inefficient, as the only meaningful information is the address.
Furthermore, this would require implementations to process these TE
link TLVs differently from others; for example, the TE metric is
normally considered a mandatory sub-TLV, but would have no meaning
for a local address
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Internet Draft draft-raggarwa-ospf-te-node-addr-00.txt September 2003
5. Proposed Solution
The proposed solution is to advertise the local addresses of a router
in a new node attribute TLV, in the OSPF TE LSA. It is anticipated
that a node attribute TLV will also prove more generally useful.
5.1. Node Attribute TLV
The node attribute TLV carries the attributes associated with a
router. The TLV type is TBD and the length is variable. It contains
one or more sub-TLVs. This document defines the following sub-TLVs:
1. Node IPv4 Local Address sub-TLV
2. Node IPv6 Local Address sub-TLV
The node IPv4 local address sub-TLV has a type of 1 and contains one
or more local IPv4 addresses. 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 1 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . .
. . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The length is set to 4 * n where n is the number of local addresses
included in the sub-TLV.
The node IPv6 local address sub-TLV has a type of 2 and contains one
or more local IPv6 addresses. 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 2 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address 1 |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Internet Draft draft-raggarwa-ospf-te-node-addr-00.txt September 2003
. . .
. . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address n |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--
The length is set to 16 * n where n is the number of local addresses
included in the sub-TLV.
6. Security Considerations
This document does not introduce any further security issues other
than those discussed in [OSPF-TE, OSPFv3-TE].
7. IANA Considerations
The Node Attribute TLV type has to be IANA assigned from the range 3
- 32767 as specified in [OSPF-TE].
8. Acknowledgments
We would like to thank Nischal Sheth for his contribution to this
work. We woud also like to thank Jean Philippe Vasseur for his
comments.
9. References
[OSPF] Moy, J., "OSPF Version 2", RFC 2328, April 1998.
[RFC] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[OSPF-TE] D. Katz, K. Kompella, D. Yeung, "Traffic Engineering
Extensions to OSPF version 2", RFC 3630,
September 2003.
[OSPFv3] R. Coltun, D. Ferguson, J. Moy, "OSPF for IPv6",
RFC 2740.
[OSPFv3-TE] K. Ishiguro, T. Takada, "Traffic Engineering
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Internet Draft draft-raggarwa-ospf-te-node-addr-00.txt September 2003
Extensions to OSPF version 3",
draft-ietf-ospf-ospfv3-traffic-01.txt.
[OSPF-TE-MESH] J. P. Vasseur, P. Psenak, "OSPF Traffic Engineering
Capability TLVs",
draft-vasseur-mpls-ospf-te-cap-00.txt.
10. Author Information
Rahul Aggarwal
Juniper Networks
1194 North Mathilda Ave.
Sunnyvale, CA 94089
Email: rahul@juniper.net
Kireeti Kompella
Juniper Networks
1194 North Mathilda Ave.
Sunnyvale, CA 94089
Email: kireeti@juniper.net
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