Redistribution issue between two routing protocol

Publication Date:  2016-12-29 Views:  246 Downloads:  0
Issue Description

There is redistribution issue between two routing protocol. For OSPF, administrative distance of internal OSPF
route is 10. But the administrative distance of external OSPF route is 150. The
administrative distance of ISIS is 15. Customer found that there is packet loss
and sometimes network unreachable from ISIS network to OSPF external route
network.



Solution

In this case, customer only performs simple redistribution without any
route protection feature. Suboptimal route occurred which resulted in network
unreachable.


To improve this situation, we use filter policy to filter the OSPF
external route at another switch in ISIS.


Two switch configuration:

Isis

Filter-policy ip-prefix filter import

Ip ip-prefix filter deny 192.168.1.0 24

Ip ip-prefix filter permit 0.0.0.0 0 less-equal 32



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