Cisco 3845 Software Guide - Page 634

Configuring ISO CLNS Routing Chapter 29 Configuring IP Unicast Routing to the default conditions for summary addressing, LSP refresh interval, LSP lifetime, LSP timers, SFP timers, and PRC timers, use the no form of the commands. Use the no partition avoidance router configuration command to disable the output format. Configuring IS-IS Interface Parameters You can optionally configure certain interface-specific IS-IS parameters, independently from other attached routers. However, if you change some values from the defaults, such as multipliers and time intervals, it makes sense to also change them on multiple routers and interfaces. Most of the interface parameters can be configured for level 1, level 2, or both. Interface level parameters: • The default metric on the interface, which is used as a value for the IS-IS metric and assigned when there is no quality of service (QoS) routing performed. • The hello interval (length of time between hello packets sent on the interface) or the default hello packet multiplier used on the interface to determine the hold time sent in IS-IS hello packets. The hold time determines how long a neighbor waits for another hello packet before declaring the neighbor down. This determines how quickly a failed link or neighbor is detected so that routes can be recalculated. Change the hello-multiplier in circumstances where hello packets are lost frequently and IS-IS adjacencies are failing unnecessarily. You can raise the hello multiplier and lower the hello interval correspondingly to make the hello protocol more reliable without increasing the time required to detect a link failure. • Other time intervals: - Complete sequence number PDU (CSNP) interval. CSNPs are sent by the designated router to maintain database synchronization - Retransmission interval. This is the time between retransmission of IS-IS LSPs for point-to-point links. - IS-IS LSP retransmission throttle interval. This is the maximum rate (number of milliseconds between packets) at which IS-IS LSPs are re-sent on point-to-point links This interval is different from the retransmission interval, which is the time between successive retransmissions of the same LSP • Designated router election priority, which allows you to reduce the number of adjacencies required on a multiaccess network, which in turn reduces the amount of routing protocol traffic and the size of the topology database. • The interface circuit type, which is the type of adjacency desired for neighbors on the specified interface • Password authentication for the interface Beginning in privileged EXEC mode, follow these steps to configure IS-IS interface parameters: Step 1 Step 2 Command configure terminal interface interface-id Step 3 isis metric default-metric [level-1 | level-2] Purpose Enter global configuration mode. Specify the interface to be configured and enter interface configuration mode. If the interface is not already configured as a Layer 3 interface, enter the no switchport command to put it into Layer 3 mode. (Optional) Configure the metric (or cost) for the specified interface. The range is from 0 to 63. The default is 10. If no level is entered, the default is to apply to both Level 1 and Level 2 routers. 29-68 Cisco ME 3800X and 3600X Switch Software Configuration Guide OL-23400-01