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JUNOSe 11.0.x IP, IPv6, and IGP Configuration Guide
on the circuit. This configuration is known as a point-to-point-over-LAN or P2P circuit.
This interface configuration tears down the current LAN adjacency that IS-IS has over
this interface. IS-IS then reestablishes the adjacency as a point-to-point connection
and regenerates the LSPs. The broadcast link is thereafter treated as simple
point-to-point interface.
Treating the LAN as a P2P circuit reduces the amount of information that IS-IS has
to maintain and manage. For example, there is no need to elect a designated router
for the interface. LSP flooding is performed as in P2P links without the need for using
periodic CSNPs.
This circuit configuration can be advantageous even when many routers are on the
LAN. For example, you might want to organize the routers into multiple smaller
VLANs so that you can assign different costs to the IS-IS neighbors. You can apply
this configuration to any such VLAN that has only two routers. IS-IS then views the
LAN as a mesh of point-to-point connections.
The use of IP unnumbered interfaces makes the most of scarce IP address resources
and provides for simpler network management and configuration. This configuration
enables IP processing on a point-to-point interface without an explicit IP address.
The IP unnumbered interface borrows the IP address of another interface on the
node. Point-to-point-over-LAN circuits separate the concept of network type from
media type, and enable you to apply unnumbered interface configurations to LANs.
The point-to-point-over-LAN feature requires the following:
isis network point-to-point
Summary Example
356
Configuring IS-IS Interface-Specific Parameters
The LAN must have only two routers.
Both routers must support the feature.
You must configure the interface at each end as a P2P connection.
If you are using numbered interfaces, both ends must be in same IPv4 subnet.
If you are using unnumbered interfaces, both ends require static ARP entry
configuration.
Use to specify that the broadcast circuit is to be treated as a point-to-point circuit.
Issuing this command tears down existing adjacencies, originates or flushes
LSPs, and establishes new adjacencies
Example
host1(config-intf)#isis network point-to-point
Use the no version to restore the default value, treating the circuit as a broadcast
circuit.
See isis network point-to-point
host1(config-router)#passive-interface loopback 0
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