CCNP / BSCI Examination Tutorial: Route Summarization Along with the OSPF Null Interface
CCNP Examination results, specially on the BSCI Test, requires you comprehend the main points of route summarization. This ability not 먹튀 simply requires that you've a consolation stage with binary conversions, but you have to know the way and the place to apply route summarization with Every particular person protocol.
You even have to find out the “Negative effects” of route summarization. With OSPF, there'll actually be an additional interface developed at The purpose of summarization, and this catches lots of CCNP candidates without warning. Allow’s Have a look at the null0 interface And the way it relates to OSPF summarization.
On R1, the following networks are redistributed into OSPF, after which summarized.
interface Loopback16
ip handle sixteen.16.sixteen.16 255.0.0.0
interface Loopback17
ip deal with seventeen.17.seventeen.seventeen 255.0.0.0
interface Loopback18
ip tackle 18.18.eighteen.18 255.0.0.0
interface Loopback19
ip tackle 19.19.19.19 255.0.0.0
R1(config)#router ospf one
R1(config-router)#redistribute related subnets
R1(config-router)#summary-handle 16.0.0.0 252.0.0.0
The summary handle appears on R2, a downstream router.
R2#show ip route ospf
O E2 16.0.0.0/6 [one hundred ten/20] via 172.twelve.123.one, 00:00:05, Serial0
Permit’s go back to R1 and evaluate its OSPF table.
R1#exhibit ip route ospf
O sixteen.0.0.0/6 is usually a summary, 00:01:fifty one, Null0
Exactly where did the null0 interface originate from, and why could it be there? Packets sent into the null interface are dropped, and In such a case, that’s a fantastic detail.
Once you configure summary routes in OSPF, a route to null0 might be put in in the OSPF routing desk. This can help to avoid routing loops. Any packets destined for that routes which were summarized will likely have a longer match from the routing table, as revealed under…
C 17.0.0.0/8 is immediately connected, Loopback17
C 16.0.0.0/8 is right linked, Loopback16
C 19.0.0.0/eight is instantly linked, Loopback19
C eighteen.0.0.0/eight is instantly connected, Loopback18
O sixteen.0.0.0/six can be a summary, 00:01:fifty one, Null0
.. and packets that don't match one of the summarized routes but do match the summary route will likely be dropped.
Blocking routing loops when executing route redistribution and summarization is vital. OSPF presents us a little bit assist in that regard in this case, and while you study more advanced redistribution eventualities on your strategy to the CCNP and CCIE, you’ll recognize that we’ll get all the assistance we could get!