Protocols And Standards - HPE FlexNetwork HSR6800 Configuration Manual

Original LSP—The LSP generated by the originating system. The system ID in its LSP ID field is the
system ID of the originating system.
Extended LSP—Extended LSPs are generated by virtual systems. The system ID in its LSP ID field is the
virtual system ID. After additional system IDs are configured, an IS-IS router can advertise more link state
information in extended LSP fragments. Each virtual system can be considered a virtual router. An extended
LSP fragment is advertised by a virtual system identified by an additional system ID.
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Operation modes:
The LSP fragment extension feature operates in the following modes:
Mode-1—Applicable to a network where some routers do not support LSP fragment extension. In this
mode, adjacencies are formed between the originating system and virtual systems, with the link cost from the
originating system to each virtual system as 0. Each virtual system acts as a router connected to the originating
system in the network, but the virtual systems are reachable through the originating system only. The IS-IS
routers not supporting LSP fragment extension can operate correctly without modifying the extended LSP
fragments received, but some limitation is imposed on the link state information in the extended LSP fragments
advertised by the virtual systems.
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. 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 by using the display command.
BFD
BFD provides a single mechanism to quickly detect any link failures between IS-IS neighbors to
reduce network convergence time.
For more information about BFD, see High Availability Configuration Guide.
MTR
IS-IS Multi-Topology Routing (MTR) splits an IS-IS routing domain into multiple independent IP
topologies, such as an IPv4 topology and an IPv6 topology. SPF computation is performed on a
per-topology basis.
IS-IS MTR comprises:
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IPv4 unicast MTR.
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IPv6 unicast MTR. For relevant information, see "Configuring IPv6 IS-IS."
For more information about MTR, see "Configuring MTR."

Protocols and standards

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ISO 10589, ISO IS-IS Routing Protocol
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ISO 9542, ES-IS Routing Protocol
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