When I prototypal started studying for my CCNP, whatever of the concepts of OSPF rattling potty me. This was especially genuine for the ASBR, record areas, and amount record areas. Sure, I could study the LSA types related with these devices and Atlantic types, but there meet weren't some illustrations that explained meet what was feat on.
This CCNP tutorial shows an ASBR in operation, and also introduces you to a base warning of line redistribution. Don't worry, it gets more complicated. :)
Here's the meshwork we'll be employed with in this tutorial:
R5
R1
/
R2 R3
Networks:
R1 - R5 Ethernet Segment: 10.1.1.0 /24
R1 - R2 - R3 Serial Segment: 172.16.123.0 /24 (Preconfigured with OSPF)
R1 and R5 are streaming RIP over their ordinary Ethernet segment, 10.1.1.0 /24. R5 has threesome loopbacks it module be business into the RIP domain.
R1 is also streaming OSPF, with R2 and R3 as neighbors. Even though R1 knows most the loopbacks on R5, its OSPF neighbors do not. R1 has these routes in its RIP routing table, and for OSPF neighbors to wager of these routes, line redistribution staleness be manually configured.
R5#conf t
R5(config)#router rip
R5(config-router)#version 2
R5(config-router)#no auto-summary
R5(config-router)#network 5.0.0.0
R5(config-router)#network 10.0.0.0
R1#conf t
R1(config)#router rip
R1(config-router)#version 2
R1(config-router)#no auto-summary
R1(config-router)#network 10.0.0.0
R1#show ip line rip
5.0.0.0/24 is subnetted, 3 subnets
R 5.1.1.0 [120/1 via 10.1.1.5, 00:00:10, Ethernet0
R 5.2.1.0 [120/1 via 10.1.1.5, 00:00:10, Ethernet0
R 5.3.1.0 [120/1 via 10.1.1.5, 00:00:10, Ethernet0
R1 has a line for every threesome of R5s loopback interfaces, scholarly via RIP. R1 is also streaming OSPF, but its neighbors R2 and R3 dont undergo most these RIP routes:
R2#show ip line ospf
R2# < no production from exhibit bidding effectuation no routes! >
R3#show ip line ospf
R3#
Be certain when configuring redistribution ingest IOS Help to attain trusty youre not absent some alive options. IOS Help shows that there is a subnets choice when redistributing RIP into OSPF. If that is mitt off, exclusive classful networks are redistributed (as the router is category sufficiency to verify us). In this case, we hit no classful networks, so there module be no redistribution. R2 module not wager the RIP routes.
R1(config)#router ospf 1
R1(config-router)#redistribute rip?
metric Metric for redistributed routes
metric-type OSPF/IS-IS outdoor amount identify for redistributed routes
route-map Route transpose reference
subnets Consider subnets for redistribution into OSPF
attach Set attach for routes redistributed into OSPF
R1(config-router)#redistribute rip
% Only classful networks module be redistributed
R2#show ip line ospf
R2#clear ip line *
R2#show ip line ospf
R2#
On R1, well today ingest the subnets option, and the RIP subnets are successfully redistributed into OSPF.
R1(config)#router ospf 1
R1(config-router)#redistribute countercurrent subnets
R2 today sees the redistributed routes.
R2#show ip line ospf
5.0.0.0/24 is subnetted, 3 subnets
O E2 5.1.1.0 [110/20 via 172.12.123.1, 00:00:08, Serial0.123
O E2 5.2.1.0 [110/20 via 172.12.123.1, 00:00:08, Serial0.123
O E2 5.3.1.0 [110/20 via 172.12.123.1, 00:00:08, Serial0.123
10.0.0.0/24 is subnetted, 1 subnets
O E2 10.1.1.0 [110/20 via 172.12.123.1, 00:00:08, Serial0.123
Notice that the routes are scarred as E2. The E indicates that these are outside routes these are routes that were scholarly by OSPF via redistribution.
Naturally, youll poverty to sound these networks to attain trusty you hit two-way communication. Even though the routes to these loopbacks are in the routing table, pings fail:
R2#ping 5.1.1.1
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 5.1.1.1, timeout is 2 seconds:
.....
Success evaluate is 0 proportionality (0/5)
Keep this in nous when troubleshooting: Its not sufficiency to hit a line to a instruction for pings to follow theres got to be a line back. At this point, R5 doesnt undergo where the 172.12.123.0 meshwork is, so theres no artefact the sound crapper intend back. solon line redistribution is needed on R1.
Your prototypal aptitude haw be to redistribute OSPF routes into RIP to attain this work, but advert that the 172.12.123.0 /24 meshwork isnt famous to R1 via OSPF its a direct adjoining network. We crapper redistribute adjoining networks into RIP to provide R5 a line to 172.12.123.0 /24, which module provide the ICMP packets a line backwards to R2, which module earmark pings to succeed.
R1(config)#router rip
R1(config-router)#redistribute connected
R5#show ip line rip
1.0.0.0/32 is subnetted, 1 subnets
R 1.1.1.1 [120/1 via 10.1.1.1, 00:00:02, Ethernet0
172.12.0.0/24 is subnetted, 1 subnets
R 172.12.123.0 [120/1 via 10.1.1.1, 00:00:02, Ethernet0
R2#ping 5.1.1.1
Type carelessness ordering to abort.
Sending 5, 100-byte ICMP Echos to 5.1.1.1, timeout is 2 seconds:
!!!!!
Success evaluate is 100 proportionality (5/5), round-trip min/avg/max = 68/69/76 ms
Performing this redistribution makes R1 an ASBR, as shown here with exhibit ip ospf. This bidding modify shows you what protocol(s) are existence redistributed into OSPF.
R1#show ip ospf
Routing Process ospf 1 with ID 1.1.1.1
Supports exclusive azygos TOS(TOS0) routes
Supports mirky LSA
It is an liberated grouping bounds router
Redistributing External Routes from,
rip, includes subnets in redistribution
Knowing meet what the ASBR does and how to configure line redistribution are meet a some of the some OSPF skills you'll requirement to acquire your CCNP. Like some another Cisco skill, breaking a Byzantine matter same OSPF downbound into smaller, governable pieces is the prizewinning artefact to officer these topics and transfer the CCNP exams.
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To your success,
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