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Configuring an ISO System Identifier for the Router

For IS-IS to operate on the router, you can optionally configure a system identifier (system ID). The system identifier is commonly the media access control (MAC) address or the IP address expressed in binary-coded decimal (BCD).

If you do not statically map the hostname, the mapping is generated dynamically, based on the system host-name. If you omit the static-host-mapping hostname sysid statement, the IS-IS system ID is dynamically generated from the host portion of the ISO address configured on the loopback interface (lo0) and is mapped to the host-name statement configured at the [edit system] hierarchy level. Run the show isis hostname command to view the mappings.

To configure an International Organization for Standardization (ISO) system ID, include the sysid statement at the [edit system static-host-mapping hostname] hierarchy level:

hostname is the name specified by the host-name statement at the [edit system] hierarchy level.

system-identifier is the ISO system identifier. It is the 6-byte system ID portion of the IS-IS network service access point (NSAP). We recommend that you use the host’s IP address represented in BCD format. For example, the IP address 192.168.1.77 is 1921.6800.1077 in BCD.

Note:

A display issue has been identified in the IS-IS protocol where the ISO address is not picked up properly, and the system identifier (system ID) does not show the correct value when loopback interfaces per routing instance are configured.

This issue affects all platforms supporting the IS-IS protocol. You notice that the system ID value in the show isis overview command output reflects the system ID of the primary instance's loopback interface for all routing instances, rather than the locally configured ISO addresses for each routing instance. Despite this display inaccuracy, the actual system IDs utilized by the IS-IS protocol remain correct and can be verified through the show isis hostname command or by inspecting IS-IS packets.

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