Configuring an NET
An NET defines the current IPv6 IS-IS area address and the system ID of a router.
Context
You can configure a maximum of three NETs on a process of a router. The area addresses of the NETs can be different, but their system IDs must be the same.
NET consists of three parts.
- Part one is the area ID that is variable (1 to 13 bytes), and the area IDs of the routers in the same area are identical.
- Part two is the system ID (6 bytes) of this router, which must be unique in the whole area and backbone area.
- Part three is the last byte "SEL", whose value must be "00".
Procedure
- Access the system view.
- Access the IS-IS process view.
isis [ process-id ]
- Configure an NET.
network-entity net
Configuring loopback interface addresses based on NETs is recommended to ensures that a NET is unique on the network. If NETs are not unique, route flapping will easily occur.
System ID used in IS-IS can be obtained in the following way: extend each part of the IP address to 3 bits, add 0 to the front of any part that is shorter than 3 bits, divide the extended address into three parts, with each part consisting of four decimal digits, and the reconstructed address is the system ID.
During the establishment of the Level-2 neighbor relationship, IS-IS does not check whether area addresses are the same. During the establishment of the Level-1 neighbor relationship, area addresses must be the same; otherwise, the Level-1 neighbor relationship cannot be established.
- Enable IPv6.