Transcript Protocol Topology Support for IS-IS

Protocol Topology Support
for IS-IS
draft-ietf-noguchi-isis-protocol-topology-01.txt
Kay Noguchi <[email protected]>
56th IETF
San Francisco, CA, USA
March 18, 2003
Contents
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RFC 1195 Restrictions
Goal
New TLV and Sub-TLV
Adjacency Formation
LSP Encoding
SPF Calculation
Migration Mechanism
Copyright © 2003 IP Infusion Inc. All Rights Reserved.
RFC 1195 Restrictions
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Every router MUST be capable of all
network layer protocols that are present
in an area.
– Can’t mix IPv4 only and IPv6 only routers
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Protocol Support capability MUST be
identical on all interfaces.
– Node oriented protocol support capability
Copyright © 2003 IP Infusion Inc. All Rights Reserved.
Goal
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IPv4 only, IPv6 only and IPv4/IPv6 dual
routers can co-exist.
– By maintaining different SPF trees for each
network layer protocols.
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Different protocol support capability on
each Interface
– Interface oriented protocol support
capability
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New TLV and Sub-TLV
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Interface Protocols Supported TLV
– Encoded in IS-IS Hello.
– Convey interface oriented protocol support
capability to neighboring routers.
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Protocols Supported Sub-TLV
– Encoded in Extended IS-Reachability TLV.
– Flood interface oriented protocol support
capability in the area.
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Adjacency Formation
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MUST drop IS-IS Hello which doesn’t contain
Interface Protocols Supported TLV.
– To avoid possible routing loop.
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Point-to-Point Interfaces
– MUST NOT form an adjacency if at least one of
the same protocol capability is not met with
neighboring router.
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Broadcast Interfaces
– MUST attempt to form an adjacency regardless of
the neighbor’s protocol capability.
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No change in DIS election.
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LSP Encoding
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Use Protocols Supported Sub-TLV.
Point-to-Point Interfaces
– ANDing local and remote side of protocol
support capability.
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Broadcast Interfaces
– Regular LSP
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Local side of protocol support capability
– Pseudo-Node LSP
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Remote side of protocol support capability
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SPF Calculation
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SPF MUST be calculated separately for
each network layer protocol.
New Protocol Supported Sub-TLV
MUST be used instead of old Protocols
Supported TLV.
– Reverse protocol support check is not
“MUST” because pseudo-node LSP also
contains Protocol Supported Sub-TLV.
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Migration Mechanism
1)
2)
3)
4)
Start to advertise new TLV and SubTLV in addition to the old TLV.
Change adjacency formation and
SPF calculation based on this draft.
Stop to advertise old TLV.
Change interface protocol support
capability appropriately.
Copyright © 2003 IP Infusion Inc. All Rights Reserved.
Questions?
Copyright © 2003 IP Infusion Inc. All Rights Reserved.
Questions to M-ISIS
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Non M-ISIS IPv4 router and M-ISIS
IPv6 router.
– How to make adjacency?
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Non M-ISIS IPv4/IPv6 dual router and
M-ISIS IPv4/IPv6 dual router.
– Possible routing loop?
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IPv6 Reachability TLV and MT
Reachable IPv6 Prefixs(M-ISIS).
– Do we need both?
Copyright © 2003 IP Infusion Inc. All Rights Reserved.