In-depth analysis of Route redistribution (1)

Key Aspect 1 of Route redistribution

When different external routing protocols are re-distributed into an AS, to prevent loop occurrence, you must set a number greater than the maximum Metric value in, as the seed measurement value. The following are the default values of various routing protocols when new routing protocols are re-released:

No matter which protocol is re-released to RIP, if no seed metric value is set, the default value is infinite. When a new route does not enter the RIP region to re-distribute the direct connection and static information to RIP, mtric value: 1)

The default seed value is infinite, which is the same as that of IGRP or OSPF and RIP.

Except that the default seed value of BGP is 1, the default seed value of OSPF is 20.

IS-IS the default seed value IS 0.

When BGP external protocols are distributed again, the IGP mtric value remains unchanged.

Key Aspect 2 of Route redistribution

In general, commands and parameters can be in different order when the following types of redistribution are often used ):

Connected: route the direct connection to the routing protocol.

Mtric: sets the seed value of the redistribution protocol.

Route-map: Route map Filtering

Static: republishing the Static route to the route table.

Key Aspect 3 of Route redistribution

Re-distributing routes to OSPF is followed by writing subnets options. Otherwise, subnets other than the primary class cannot be re-distributed to the route table. The default mtric type is O * E2.