1. Routing to be redistribute INTO the Router
To redistribute OSPF
conf t
Router RIP
redistribute OSPF
To redistribute EIGRP
conf t
Router OSPF
redistribute EIGRP
Redistribution Issues
2. Sub Optimal Routing
3. Routing Loops
Work Around for Redistribution
1. Tweek Administrative Distance in OSPF
2. Route Tagging to allow and block
3. Prefix List to allow and block
4. Access-list to allow and block
BASIC ROUTE REDISTRIBUTION
RIP-----------RT1-----------RT2-----------RT3--------OSPF
10.1.1.0/24 172.16.1.0/24 172.16.2.0/24 172.17.1.0/24
10.1.2.0/24 172.17.2.0/24
10.1.3.0/24 172.17.3.0/24
10.1.4.0/24 172.17.4.0/24
10.1.5.0/24 172.17.5.0/24
10.1.6.0/24 172.17.6.0/24
Router 2
conf t
router rip
redistribute ospf 1 metric 5
or
conf t
router rip
redistribute ospf 1
default-metric 5
Router 1
show ip route
Router 2
conf t
router ospf
redistribute rip metric 100 subnets metric-type [1 or 2] 2
1 external type 1 metric - adding the cost of links
2 external type 2 metric - shows the same metric of 100
Router 3
show ip route
REDISTRIBUTION WITH DISTRIBUTION LIST
Filtering 2 Statements
RIP-----------RT1-----------RT2-----------RT3--------OSPF
10.1.1.0/24 172.16.1.0/24 172.16.2.0/24 172.17.1.0/24
10.1.2.0/24 172.17.2.0/24
10.1.3.0/24 172.17.3.0/24
10.1.4.0/24 172.17.4.0/24
10.1.5.0/24 172.17.5.0/24
10.1.6.0/24 172.17.6.0/24
Router 2
conf t
access-list 1 permit 172.17.1.0 0.0.0.255
access-list 1 permit 172.17.2.0 0.0.0.255
router rip
distrubute-list 1 out
Router 1
show ip route
clear ip route
show ip route
Router 2
conf t
access-list 2 deny 10.1.1.0 0.0.0.255
access-list 2 deny 10.1.2.0 0.0.0.255
access-list 2 deny 10.1.3.0 0.0.0.255
access-list 2 deny 10.1.4.0 0.0.0.255
access-list 2 permit any
router ospf 1
distribute-list 2 out
Router 3
show ip route
clear ip route
show ip route
REDISTRIBUTION WITH PREFIX LIST
1.Alternative for access-list (Matching Routes)
- Improve Processor Utilization
- Better subnet mask matching abilities
2. 2 stage matching network and subnet mask
3. Similar to ACL
ip prefix-list ABA permit 172.30.0.0/16 ge 20 (ge=greater than)
a. 172.30.1.0/24 OK
b. 172.30.0.0/16
c. 172.30.32.0/19
d. 172.16.0.0/18
e. 172.30.10.0/24 OK
ip prefix-list ABA permit 172.30.0.0/16 le 20 (le=less than)
a. 172.30.1.0/24
b. 172.30.0.0/16 OK
c. 172.30.32.0/19 OK
d. 172.16.0.0/18
e. 172.30.10.0/24
REDISTRIBUTION WITH ROUTE-MAPS
2. Peform a series of IF > then statement called match/set
1. Order list of statements similar to Access-list
3. Typically used for:
- modify bgp attributes
- policy routing
- route filtering
ROUTER 2
conf t
router rip
redistribute ospf 1 metric 5 subnets
ROUTER 1
show ip route
ROUTER 2
conf t
access-list 5 permit 10.1.1.0 0.0.0.255
access-list 5 permit 10.1.2.0 0.0.0.255
access-list 5 permit 10.1.3.0 0.0.0.255
access-list 6 permit 172.17.1.0 0.0.0.255
access-list 6 permit 172.17.2.0 0.0.0.255
access-list 6 permit 172.17.3.0 0.0.0.255
route-map ABA permit 10
match ip address 5
exit
show route-map
route-map
set metric 1000
show route-map
router ospf 1
ROUTER 2
conf t
router ospf 1
redistribute rip route-map ABA subnets
ROUTER 3
show ip route
ROUTER 2
route-map ABA permit 20
set metric 500
ROUTER 3
show ip route
REDISTRIBUTION WITH PREFIX-LIST
Router 3
conf t
ip prefix list ABA permit 10.0.0.0/8
ip prefix list ABA permit 10.0.0.0/8 le 24
router ospf 1
redistribute rip metric 100 subnets
route map RM permit 10
match ip address prefix list ABA
match ip address prefix list ABA
match ip address prefix list ABA2
match ip address prefix list ABA3
or
match ip address prefix list ABA ABA2 ABA3
router ospf 1
redistribute rip metric 100 subnet route-map RM
Router 3
show ip route
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