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IPv6 IS-IS Configuration
IPv6 IS-IS supports all the features of IPv4 IS-IS except that it advertises IPv6 routing information
instead. This document describes only IPv6 IS-IS exclusive configuration tasks. For other configuration
tasks, refer to
IS-IS Configuration
in the
IP Routing Volume
.
When configuring IPv6 IS-IS, go to these sections for information you are interested in:
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Introduction to IPv6 IS-IS
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Configuring IPv6 IS-IS Basic Functions
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Configuring IPv6 IS-IS Routing Information Control
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Displaying and Maintaining IPv6 IS-IS
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IPv6 IS-IS Configuration Example
Introduction to IPv6 IS-IS
The IS-IS routing protocol (Intermediate System-to-Intermediate System intra-domain routing
information exchange protocol) supports multiple network protocols, including IPv6. IS-IS with IPv6
support is called IPv6 IS-IS dynamic routing protocol. The international engineer task force (IETF)
defines two type-length-values (TLVs) and a new network layer protocol identifier (NLPID) to enable
IPv6 support for IS-IS.
TLV is a variable-length field in the link state PDU or link state packet (LSP). The two TLVs are:
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IPv6 Reachability: Defines the prefix, metric of routing information to indicate network reachability,
and has a type value of 236 (0xEC).
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IPv6 Interface Address: Same as the “IP Interface Address” TLV in IPv4 ISIS, except that the 32-bit
IPv4 address is translated to the 128-bit IPv6 address.
The NLPID is an 8-bit field that identifies which network layer protocol is supported. For IPv6, the NLPID
is 142 (0x8E), which must be carried in hello packets sent by a router that supports IPv6 IS-IS.
For information about IS-IS, refer to
IS-IS Configuration
in the
IP Routing Volume
.
