3com S7906E インストール手順

 

1-18 

z 

Configure the IS level of all routers as Level-1 or Level-2 and don’t configure different levels in this 

case because there is no need for all routers to maintain two identical LSDBs;  

z 

Configure the IS level as Level-2 on all routers in an IP network for scalability. 

For an interface of a Level-1 (or Level-2) router, the circuit level can only be Level-1 (or Level-2). For an 

interface of a Level-1-2 router, the default circuit level is Level-1-2; if the router only needs to form 

Level-1 (or Level-2) neighbor relationships, you can configure the circuit level for its interfaces as 

Level-1 (or Level-2) to limit neighbor relationship establishment. 

Follow these steps to configure the IS level and circuit level: 

Enter system view 

–– 

Enter IS-IS view 

isis [ process-id ] 
[ vpn-instance 
vpn-instance-name ] 

–– 

Specify the IS level 

is-level { level-1 | level-1-2 | 
level-2 } 

Optional 

The default is Level-1-2. 

Return to system view 

–– 

Enter interface view 

interface interface-type 
interface-number 

–– 

Specify the circuit level 

isis circuit-level [ level-1 | 
level-1-2 | level-2 ] 

Optional 

The default is Level-1-2. 

 

Interfaces with different network types operate differently. For example, broadcast interfaces on a 

network need to elect the DIS and flood CSNP packets to synchronize the LSDBs, while P2P interfaces 

on a network need not elect the DIS and have a different LSDP synchronization mechanism. 

If there are only two routers on a broadcast network, you can configure the network type of attached 

interfaces as P2P to avoid DIS election and CSNP flooding, saving network bandwidth and speeding up 

network convergence. 

Follow these steps to configure the network type of an interface: 

Enter system view 

–– 

Enter interface view 

interface interface-type 
interface-number 

–– 

Configure the network type for the 
interface as P2P 

Optional 

By default, the 
network type of an 
interface depends 
on the physical 
media. The network 
type of a VLAN 
interface is 
broadcast.