System information

Configuring IS-IS
10-9
Summarizing IP Address Ranges
A range of IP addresses listed in an LSP can be represented by a summary address.
Routes learned from other routing protocols also can be summarized. The metric used
to advertise the summary is the smallest metric of all the more specific routes.
Use the summary-address command in Router Configuration mode to create a
summary address for a range of IP addresses, as shown below:
MOT(config-isis)#summary-address <ip-address> <mask> {level-1 | level-1-2
| level-2}
Enabling the LSP Overload Bit
The LSP overload bit is enabled for the IS-IS routing process to ensure that no paths
through the BSR are seen by other routers in the IS-IS area when the Link State
routing table on the BSR is incomplete or inaccurate. However, IP and CLNS prefixes
directly connected to the BSR continue to be reachable.
Use the set-overload-bit command in Router Configuration mode to allow other
routers on the network to ignore IS-IS routing problems on the BSR in their SPF
calculations until the IS-IS routing process on the BSR has recovered from its
problems, as shown below:
MOT(config-isis)#set-overload-bit
Configuring a Passive Interface for IS-IS
You can configure a passive interface to prevent other routers on a local network from
learning about routes dynamically. A passive interface does not transmit routing
updates.
Use the passive-interface command in Router Configuration mode to create a passive
IS-IS interface, as shown in the following example:
MOT(config-isis)#passive-interface {cable | ethernet | gigaether | pos}
<slot>/<interface>
where: