Source-Based Policies

Source-Based Policies
Source-based policy routing allows you to make the routing decisions based on where the traffic
originates. Refer to Figure 10.3.
FIGURE 1 0 . 3 Source-based policies
We need to create a policy on R1 that will send the traffic from network 192.168.200.0 /24
destined for network 192.168.50.0 /24 and network 192.168.100.0 /24 out R1’s ATM0/0 interface.
All other traffic destined for these networks needs to be routed across R1’s S1/0 interface.
R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#access-list 100 permit ip 192.168.200.0 0.0.0.255
➥192.168.50.0 0.0.0.255
R1(config)#access-list 100 permit ip 192.168.200.0 0.0.0.255
➥192.168.100.0 0.0.0.255
R1(config)#access-list 110 permit ip any 192.168.50.0 0.0.0.255
R1(config)#access-list 110 permit ip any 192.168.100.0 0.0.0.255
R1(config)#route-map POLICY1 permit 10
R1(config-route-map)#match ip address 100
R1(config-route-map)#set interface atm0/0
R1(config-route-map)#route-map POLICY1 permit 20
R1(config-route-map)#match ip address 110
R1(config-route-map)#set interface s1/0
R1(config-route-map)#exit
R1(config)#interface s1/1
192.168.100.0 /24
.1
.1
.1
.1
.1
.1
.1
.1
.2
.2
.2
ATM0/0 ATM0/0
S0
S1/1
E2/1
E2/1
E2/0
E2/0
E0
192.168.50.0 /24
10.10.10.0 /30
20.20.20.0 /30
S1/0
S1/0
30.30.30.0 /30
R2
R3
192.168.24.0 /24
192.168.88.0 /24
192.168.200.0 /24
R1
330 Chapter 10  Route Optimization
R1(config-if)#ip policy route-map POLICY1
R1(config-if)#exit
R1(config)#interface e2/0
R1(config-if)#ip policy route-map POLICY1
R1(config-if)#exit
R1(config)#interface e2/1
R1(config-if)#ip policy route-map POLICY1
R1(config-if)#^Z
R1#
By using the keyword default before interface or next-hop (to be illustrated
next) in the set clause, you can allow the interfaces and next hops of explicit
routes to take precedence, with these settings coming into play only when such
explicit routes do not exist. The examples here override an