9.5 Default Metrics for Redistributed Routes

Here are the redistribution configurations associated with the previous “boundary router” example between OSPF 10 and EIGRP 100.

redistribute eigrp subnets – EIGRP networks will be redistributed into the OSPF process. The subnets keyword allows for the redistribution of VLSM networks, and if it is omitted, only EIGRP routes at classful boundaries will be redistributed.

metric 60 – specifies that the new OSPF routes from the EIGRP 100 process will have a metric of 60 (cost). If not specified, the default cost is 20. Redistributed routes appear as O E2 routes in the routing table.

redistribute ospf 10 – OSPF networks will be advertised into the EIGRP process. The “10” names the specific process for redistribution. Note the OSPF routes can be granted a unique and authoritative metric if the metric <metric> keywords are appended onto the command.

default-metric – establishes a seed metric that all routes redistributed into EIGRP will have unless specified with a metric next to their redistribute command as in the following:

… the metric x command indicates the redistributed protocol RIP will have a unique metric, which overrides the seed metric.

The values of 1000, 100, 250, 100 and 1500 stand for bandwidth, delay, reliability, load, and MTU, respectively.

Here are some other characteristics of routing protocols that receive redistributed routes.

RIP = Uses hop count. Redistributed routes from other routing protocols are infinity by default, thereby insuring the routes are not injected into the routing table unless a seed metric is provided.

EIGRP = Uses bandwidth and delay. Redistributed routes from other routing protocols are infinity by default, thereby insuring the routes are not injected into the routing table unless a seed metric is provided.

OSPF = Uses cost. Redistributed routes are external Type 2 routes with a default cost of 20, except for redistributed BGP routes, which have a default type 2 metric of 1.

BGP = Routes maintain the IGP routing metrics.