When you suppress authentication of CSNPs, the router does not authenticate CSNP
packets that it receives from neighboring routers, nor does it include authentication
information in CSNP packets that it sends to other routers. Similarly, when you
suppress authentication of PSNPs, the router neither authenticates PSNP packets that
it receives nor sends authentication information in PSNP packets that it transmits.
Extensions for Traffic Engineering
The router supports new-style TLV tuples described in the Internet draft, IS-IS
Extensions for Traffic Engineering. The router ID TLV (TLV type 134) contains the ID
of the router that originates the LSP, providing a stable address that can always be
referenced regardless of the state of node interfaces.
The extended IP reachability TLV (type 135) carries IP prefixes and is similar to the
IP reachability TLVs (types 128 and 130). The extended IS reachability TLV (type 22)
contains information about a series of IS neighbors and is similar to the IS neighbor
TLV (type 2).
The older TLVs 2, 128, 130 each have a narrow metric field, providing for metric
values ranging only from 0–63. The new TLVs 22 and 135 have a new data
structure that includes a wide metric field of 3 bytes (extended IS reachability;
configurable) or four bytes (extended IP reachability; calculated). Both new TLVs
provide for the use of sub-TLVs to carry more information about IS neighbors;
however, only the extended IS reachability TLV currently has defined sub-TLVs, such
as IPv4 interface and neighbor addresses.
Use the metric-style commands to configure what style the router generates and
accepts. The following behaviors are supported:
Refer to the Internet draft, IS-IS Extensions for Traffic Engineering, for more
information about these extensions.
The area-authentication { csnp | psnp } command enables or disables simple
authentication or HMAC MD5 authentication of IS-IS level 1 CSNP packets or
PSNP packets. By default, authentication of CSNPs and PSNPs is disabled.
The domain-authentication { csnp | psnp } command enables or disables simple
authentication or HMAC MD5 authentication of IS-IS level 2 CSNP packets or
PSNP packets. By default, authentication of CSNPs and PSNPs is disabled.
Generates and accepts only old-style metrics
Generates only old-style metrics, but accepts old style and new style
Generates and accepts both old-style and new-style metrics (this option consumes
the most system resources)
Generates only new-style metrics, but accepts old style and new style
Generates and accepts only new-style metrics
Chapter 6: Configuring IS-IS
333
Overview
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