Configure IS-IS Layer Attribute

Configuration Condition

Before configuring the IS-IS layer attribute, first complete the following tasks:

• Configure the IP address of the interface to enable the neighboring nodes to be reachable at the network layer.
• Enable the IS-IS protocol.

Configure IS-IS Layer Attribute

The IS-IS layer attribute is divided into the global layer attribute and the interface layer attribute. The global layer attribute is the IS-IS intermediate system, which is further classified into the following three types:

• Level-1 intermediate system: Only the link status database of Level-1 is available and only the routing in the Level-1 area can be advertized and learnt.
• Level-2 intermediate system: Only the link status database of Level-2 is available and only the routing in the Level-2 area can be advertized and learnt.
• Level-1-2 intermediate system: Both the link status database of Level-1 and Level-2 are available and both the routing in the Level-1 and Level-2 area can be advertized and learnt. The Level-1-2 intermediate system is the interconnection device in the Level-1 and Level-2 area.

The layer attribute of the IS-IS interface is classified into the following three types:

• Level-1 attribute interface: Only the Level-1 packet of the IS-IS protocol can be transmitted and received and only the neighbor of Level-1 can be established.
• Level-2 attribute interface: Only the Level-2 packet of the IS-IS protocol can be transmitted and received and only the neighbor of Level-2 can be established.
• Level-1-2 attribute interface: Both the Level-1 packet and Level-2 packet of the IS-IS protocol can be transmitted and received and both the neighbors of Level-1 and Level-2 can be established.

The IS-IS interface layer attribute depends on the IS-IS global layer attribute. The Level-1 intermediate system only has the interface of Level-1 attribute, the Level-2 intermediate system only has the interface of Level-2 attribute, and the Level-1-2 intermediate system can has interfaces of all attributes.

Table 9-4 Configure the IS-IS global layer attribute

Table 9-5 Configure the IS-IS interface layer attribute

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  Only one IS-IS process with the Level-2 attribute is available in a VRF.

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