configure isis link-type

configure isis [vlan all | {vlan} vlan_name] link-type [broadcast | point-to-point]


This command specifies the link type for one or all IS-IS VLAN (Virtual LAN)s.

Syntax Description

vlan all Applies the link type configuration to all IS-IS VLANs.
vlan_name Specifies a single IS-IS VLAN to which the link type configuration is applied.
broadcast Selects the broadcast link type for the specified VLANs.
point-to-point Selects the point-to-point link type for the specified VLANs.



Usage Guidelines

On broadcast interfaces, a DIS is elected. There is no DIS election on point-to-point interfaces. If it is known that only two routers will be present on a physical network, it may be desirable to set their connecting interfaces to point-to-point mode. This reduces the overhead associated with DIS election and periodic CSNP transmissions and processing. In addition, if the adjacency is both level 1 and level 2, only one set of hello PDUs are sent on a point-to-point interface whereas hello PDUs are sent for both levels on broadcast interfaces. Interfaces in point-to-point mode must have an IP address assigned to them. Unnumbered interfaces are not supported.

For point-to-point interfaces, level 1 parameters apply to L1-only and L1/L2 interfaces. Level 2 parameters apply to L2-only point-to-point interfaces.


The following command configures all IS-IS VLANs to use the broadcast link type:

configure isis vlan all link-type broadcast


This command was first available in ExtremeXOS 12.1.

Platform Availability

This command is available on platforms with a Core license.