immediately, sending updates to their neighbors. Because all the routers will ignore any new
information about this subnet for holddown time, fast propagation of the fact that the route
failed is not harmful. This mechanism quickly prevents packets from being unnecessarily
routed.
protocols to help avoid loops and speed convergence.
implement distance vector logic. RIP and IGRP both use distance vector logic, so they are very
similar in many respects. A couple of major differences exist, however, and will be explained
in the upcoming text. Table 6-11 outlines the features of RIP and IGRP.
bandwidth and delay settings on the interface on which the update was received. By using
bandwidth and delay, the metric is more meaningful; longer hop routes over faster links can be
considered better routes.
in the update signifies the number of routers between the router receiving the update and each
subnet. Before sending an update, a router increments its metric for routes to each subnet by 1.
In other words, a routing update includes metric values that tell the receiving router what its
metrics should be.
network are desired. This topic is discussed in the upcoming section "Configuration of RIP and
IGRP."
delay (default); can include
reliability, load, and MTU