Routing with different protocols

[IT Anil Sikar]

There are three possible routes for a router to reach a
destination network. The first route is from OSPF with a metric
of 782. The second route is from RIPv2 with a metric of 4. The
third is from EIGRP with a composite metric of 20514560.
Which route will be installed by the router in its routing table?

@cisco 

[Harold Ritter · Accepted solution]

Hi @IT Anil Sikar ,

The lowest administrative distance will be used to installed the route in the routing table. The above mentioned routing protocols have the following administrative distances: EIGRP (90), OSPF (110) and RIP (120).

The EIGRP route will therefore be installed in the routing table.

Regards,

[Joseph W. Doherty · Accepted solution]

BTW, the AD values @Harold Ritter mentions are the defaults, which can be changed.

[MHM Cisco World · Accepted solution]

The rule is 

The lowest AD 

If ad same then tiebreak will be metric 

If metric same then router will use ECMP

MHM

[Joseph W. Doherty]

"If ad same then tiebreak will be metric 

If metric same then router will use ECMP"

Hmm, recall a prior question about what happens when different routing protocols are used when they have same (non-default) AD.  I vaguely recall (???) tie breaking was not done by a route's internal metric but by default AD values.

For example if I have an EIGRP and an OSPF route each with an AD of 100, EIGRP route would be used.

[IT Anil Sikar]

@Harold Ritter @MHM Cisco World @Joseph W. Doherty Routing with different protocols Thank you Sir

[MHM Cisco World]

You are so welcome 

MHM

[Harold Ritter]

you are very welcome @IT Anil Sikar and thanks for the feedback