3com S7906E Manuel De Montage

 

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IP Interface Address 

IIH, LSP 

 

Code 1 to 10 of CLV are defined in ISO 10589 (code 3 and 5 are not shown in the table), and others are 

defined in RFC 1195. 

IS-IS supports multiple instances and processes. Multiple processes allow a IS-IS process to work in 

concert with a group of interfaces. This means that a router can run multiple IS-IS processes, and each 

process corresponds to a unique group of interfaces. 

For routers supporting VPN, each IS-IS process is associated with a VPN instance. Thus, the VPN 

instance is also associated with interfaces corresponding to the process. 

A distributed router supports IS-IS Hot Standby (HSB). The data is copied from the Active Main Board 

(AMB) to the Standby Main Board (SMB). Whenever the AMB is down, the SMB can switch to the active 

status to run IS-IS. 

There are two kinds of IS-IS HSB. One is IS-IS data synchronization backup. After switching from AMB 

to SMB, IS-IS can work immediately. 

The other HSB is to backup only the configuration information of IS-IS during the switching from AMB to 

SMB. After the graceful restart (GR), the IS-IS router will send requests to neighbors to synchronize the 

LSDB. 

 

For detailed GR information, refer to GR Configuration in the High Availability Volume. 

 

After an IS-IS GR Restarter restarts IS-IS, it needs to complete the following two tasks to synchronize 

the LSDB with its neighbors. 

z 

To obtain effective IS-IS neighbor information without changing adjacencies. 

z 

To obtain the LSDB contents.  

After the restart, the GR Restarter will send an OSPF GR signal to its neighbors to keep the adjacencies. 

After receiving the responses from neighbors, the GR Restarter can restore the neighbor table. 

After reestablishing neighborships, the GR Restarter will synchronize the LSDB and exchange routing 

information with all adjacent GR capable neighbors. After that, the GR Restarter will update its own 

routing table and forwarding table based on the new routing information and remove the stale routes. In 

this way, the IS-IS routing convergence is complete.