Route Maps

Front 1

Route map example - Redistributing OSPF in to RIP

Back 1

#access-list permit 192.168.1.0 0.0.0.255

#route-map OSPF_into_RIP deny 10
#match ip address 1

#route-map OSPF_into_RIP permit 20

#router rip
#redistribute ospf 10 route-map OSPF_into_RIP

#router ospf 10
#redistribute subnets

this route map does not allow the address 192.168.1.0 to be redistributed, but allows all other addresses to be redistributed.

Front 2

Using Route maps with Tags - redistributing RIP to EIGRP

Back 2

#route-map rip_to_eigrp deny 10
#match tag 88

#route-map rip_to_eigrp permit 20
#set tag 77

#router eigrp 7
#redistribute rip route-map rip_to_eigrp metric 10000 1000 255 1 1500

Front 3

Using Route maps with redistribution - RIP to OSPF

- allow ip address 10.1.0.0 0.0.255.255 & 172.16.1.0 0.0.0.255 and set metric to 5000 with external type 2

- deny ip address 10.0.0.0 0.255.255.255

- allow all other routes but set metric to 5000 and set to external type 2

Back 3

#router ospf 10
#redistribute rip route-map REDIS-RIP subnets

#route-map REDIS-RIP permit 10
#match ip address 23 29
#set metric 500
#set metric-type type-1

#route-mao REDIS-RIP deny 20
#match ip address 37

#route-map REDIS-RIP permit 30
#set metric 5000
#set metric-type type-2

#access list 23 permit 10.1.0.0 0.0.255.255
#access list 29 permit 172.16.1.0 0.0.0.255
#access-list 37 permit 10.0.0.0 0.255.255.255

If a match is found for sequence number 10 the router will redistribute the route in to OSPF with a cost metric of 500 and sets the new OSPF route to external type 1

if there is no match to seq number 10 seq number 20 is then checked, if there is a match, that route is not redistributed in to OSPF because seq number 20 specifies a deny statement.

If there is no match in seq 20 then seq 30 is checked. As there is no match criteria set, all remaining routes are redistributed in to OSPF with a cost of 5000 and an external metric of type 2

Front 4

Distribute lists in Vs out

Back 4

Distribute-list in - filters updates going in to the interface specified in the command, in to the routing process under which it is configured.

Distribute-list out - filters updates going out of the interface or routing protocol specified in the command, in to the routing process under which it is configured.

Front 5

Network 10.0.0.0 needs to be hidden from network 192.168.5.0 using a distribute list applied to Router B

Back 5

RB#router eigrp 1
RB#network 172.16.0.0
RB#network 192.168.5.0
RB#distribute-list 7 out s0/0/0

RB#access-list 7 permit 172.16.0.0 0.0.255.255

- the distribute list out command applies access list 7 to packets going out interface s0/0/0

- the access-list allows onlu routing info about network 172.16.0.0 to be distributed out of s0/0/0

- the implicit deny at the end of the access list prevents updates about any other networks from being advertises, as a result network 10.0.0.0 is hidden.

- another way of filtering 10.0.0.0 would be to deny network 10.0.0.0 and permit any other networks

Front 6

Controlling Redistribution with Distribute lists - example in which redistribution is configured both ways between RIPv2 and OSPF (two way redistribution)

Back 6

Configuration for router B

#router ospf 1
#network 10.0.0.8 0.0.0.3 area 0
#redistribute rip subnets
#distribute-list 2 out rip

#router rip
#network 10.0.0.0
#version 2
#passive-interface s0/0/3
#redistribute ospf 1 metric 5
#distribute-list 3 out ospf 1

#access-list 2 deny 10.8.0.0 0.3.255.255
#access-list 2 permit any

#access-list 3 permit 10.8.0.0 0.3.255.255

- Router B redistributes the networks it learns via RIPv2 (in this case 10.1.0.0 to 10.3.0.0) in to OSPF.

- without filtering route feedback could occur if OSPF on Router D, the other redistribution point, redistributes those same networks back in to RIP.

-therefore the config example includes a distribute list that prevents route feedback.

-Access list 2 denies the routes originating in the OSPF network (10.8.0.0 through 10.11.0.0) and permits all others.

- the distribute list config under OSPF refers to this access list.


- the result is that networks 10.8.0.0 - 10.11.0.0 originated by OSPF are not redistributed back in to OSPF from RIPv2.

-All other routes are redistributed in to OSPF.

- Redistribution from OSPF in to RIPv2 is filtered with access list 3. it permits routes 10.8.0.0 - 10.11.0.0 to be redistributed into RIPv2.