H3C Technologies H3C S7500E Series Switches - Manual (Page 161)

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z Mode-2: Applicable to a network where all the routers support LSP fragment extension. In this
mode, all the IS-IS routers know which virtual system belongs to which originating system;
therefore, no limitation is imposed on the link state information of the extended LSP fragments
advertised by the virtual systems.
The operation mode of LSP fragment extension is configured based on area and routing level. Mode-1
allows the routers supporting and not supporting LSP fragment extension to interoperate with each
other, but it restricts the link state information in the extended fragments. Mode-2 does not restrict the
link state information in the extended fragments, and is recommended for an area where all the routers
are at the same routing level and support LSP fragment extension.
Dynamic host name mapping mechanism
The dynamic host name mapping mechanism provides the mappings between the host names and the
system IDs for the IS-IS routers. The dynamic host name information is announced in the dynamic
host name CLV of an LSP.
This mechanism also provides the mapping between a host name and the DIS of a broadcast network,
which is announced in the dynamic host name TLV of a pseudonode LSP.
A host name is easier to remember than a system ID. After enabling this feature on the router, you can
see the host names instead of system IDs using the display command.
BFD
For more information about BFD, see BFD Configuration in the High Availability Configuration Guide.
Bidirectional forwarding detection (BFD) provides a single mechanism to quickly detect and monitor
the connectivity of links between IS-IS neighbors, thus reducing network convergence time.
Protocols and Standards
z ISO 10589 ISO IS-IS Routing Protocol
z ISO 9542 ES-IS Routing Protocol
z ISO 8348/Ad2 Network Services Access Points
z RFC 1195: Use of OSI IS-IS for Routing in TCP/IP and Dual Environments
z RFC 2763: Dynamic Hostname Exchange Mechanism for IS-IS
z RFC 2966: Domain-wide Prefix Distribution with Two-Level IS-IS
z RFC 2973: IS-IS Mesh Groups
z RFC 3277: IS-IS Transient Blackhole Avoidance
z RFC 3358: Optional Checksums in ISIS
z RFC 3373: Three-Way Handshake for IS-IS Point-to-Point Adjacencies
z RFC 3567: Intermediate System to Intermediate System (IS-IS) Cryptographic Authentication
z RFC 3719: Recommendations for Interoperable Networks using IS-IS
z RFC 3786: Extending the Number of IS-IS LSP Fragments Beyond the 256 Limit