Policy Based Routing

The prupose is to defined a specified route different from the one in the routing table for a type of traffic.
For example 2 routers are interconnected by 2 differents links for backup purpose but you want to use the backup for FTP traffic in order to not overload the primary line.

1 Define the traffic to be matched

access-list 198 permit tcp any any eq ftp
class-map match-all PBR
match acces-group 198

2 Define the new route for the matched traffics

route-map PBR permit 10
match ip address 198
set ip next-hop X.X.X.X

3 Apply on the incoming interface

int fa0/0
ip policy route-map PBR


Remark : If you want the PBR rule applies to the traffic for/from the router itself add thje following command

ip local policy route-map PBR

Verification : you could verify matched traffic with sh route-map command

route-map PBR, permit, sequence 10
Match clauses:
ip address (access-lists): 198
Set clauses:
ip next-hop 132.1.23.3
Policy routing matches: 35 packets, 3990 bytes
route-map PBR, permit, sequence 20
Match clauses:
Set clauses:
Policy routing matches: 20 packets, 1740 bytes