Propagating LSPs on a Point-to-Point Interface
A point-to-point link does not need to ensure that multiple systems have synchronized databases. With only one other router with which to work, some reliance is given to the router's capability to determine the need to update so that bandwidth can be optimized. The following list describes the point-to-point flooding process: 1. When an adjacency is established, both sides send a complete sequence number packet (CSNP) with a compressed version of their link-state datab..
By default, the SPF algorithm runs at least every five seconds, under stable network conditions, even though network events such as adjacency changes could trigger immediate SPF runs. Running SPF on a very large LS database requires tremendous processor resources, so a high frequency of runs could be disastrous to the router and the network. The spf-interval command adjusts the frequency at which SPF runs. This command was set for periodic intervals, and SPF runs at 30 ..
Comparison of the IS-IS Restart Mechanisms
The advantages of the IETF IS-IS restart approach include scalability (does not require IS-ISrelated state preservation across the restart) and standards-based implementation. Disadvantages of this approach are that it requires IS-IS protocol extensions and support from its neighbors (helper nodes). To elaborate on this further, consider a router R1 in a provider's network that is peering with an R2 that might be managed by another provider or a customer. The IETF IS-IS resta..
RFC 1973 and Cisco Implementation of PPP over Frame Relay
RFC 1661 defines the standard PPP specifications, whereas a separate RFC document, RFC 1973, describes a standard method for transporting PPP over a Frame Relay VC connection. Cisco's implementation of the PPP over Frame Relay feature is based on the RFC 1973 specifications. A Cisco router supporting the PPP over Frame Relay feature is able to establish an end-to-end PPP session over an active Frame Relay PVC. NOTE Note that Cisco's implementation of RFC 1973 to suppor..
By default, VTP pruning is disabled on IOS-based switches. To enable pruning, use the following global configuration command: Switch(config)# vtp pruning If you use this command on a VTP server, it also advertises that pruning needs to be enabled for the entire management domain. All other switches listening to that advertisement also will enable pruning. When pruning is enabled, all general-purpose VLANs become eligible for pruning on all trunk links, if needed. Howeve..
