Configuring Integrated IS-IS
Miscellaneous IS-IS Parameters Configuration Task List
IPC-285
Cisco IOS IP Configuration Guide
Configuring IS-IS Authentication Passwords
You can assign passwords to areas and domains.
The area authentication password is inserted in Level 1 (station router level) LSPs, and the routing domain
authentication password is inserted in Level2 (area router level) LSPs.
To configure either area or domain authentication passwords, use the following commands in router
configuration mode, as needed:
Summarizing Address Ranges
You can create aggregate addresses that are represented in the routing table by a summary address. This
process is called route summarization. One summary address can include multiple groups of addresses
for a given level. 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.
To create a summary of addresses for a given level, use the following command in router configuration
mode:
Setting the Overload Bit
You can configure the router to set the overload bit (also known as the hippity bit) in its nonpseudonode
LSPs. Normally the setting of the overload bit is allowed only when a router runs into problems. For
example, when a router is experiencing a memory shortage, the link-state database may not be complete,
resulting in an incomplete or inaccurate routing table. By setting the overload bit in their LSPs, other
routers can ignore the unreliable router in their shortest path first (SPF) calculations until the router has
recovered from its problems.
The result will be that no paths through this router are seen by other routers in the IS-IS area. However,
IP and CLNS prefixes directly connected to this router will be still be reachable.
This command can be useful when you want to connect a router to an IS-IS network, but do not want
real traffic flowing through it under any circumstances. Examples are as follows:
•A test router in the lab, connected to a production network.
•A router configured as an LSP flooding server, for example, on an NBMA network, in combination
with the mesh-group feature.
•A router that is aggregating virtual circuits (VCs) used only for network management. In this case,
the network management stations must be on a network directly connected to the router with the
set-overload-bit router configuration command configured.
Command Purpose
Router(config-router)# area-password password Configures the area authentication password.
Router(config-router)# domain-password password Configures the routing domain authentication password.
Command Purpose
Router(config-router)# summary-address
address mask {level-1 | level-1-2 | level-2}
Creates a summary of addresses for a given level.