CCNP / BSCI Examination Tutorial: Route Summarization And also the OSPF Null Interface
CCNP Examination success, especially about the BSCI Test, demands you understand the small print of route summarization. This skill not just necessitates you have a comfort and ease stage with binary conversions, but It's important to understand https://en.wikipedia.org/wiki/?search=토토사이트 how and where to apply route summarization with each unique protocol.
You also have to be aware of the “Unwanted effects” of route summarization. With OSPF, there will basically be an extra interface developed at The purpose of summarization, and this catches lots of CCNP candidates without warning. Let’s Consider the null0 interface And exactly how it pertains to OSPF summarization.
On R1, the following networks are redistributed into OSPF, and then summarized.
interface Loopback16
ip tackle sixteen.16.sixteen.sixteen 255.0.0.0
interface Loopback17
ip handle seventeen.seventeen.17.17 255.0.0.0
interface Loopback18
ip handle 18.eighteen.eighteen.eighteen 255.0.0.0
interface Loopback19
ip deal with 19.19.19.19 255.0.0.0
R1(config)#router ospf one
R1(config-router)#redistribute related subnets
R1(config-router)#summary-handle sixteen.0.0.0 252.0.0.0
The summary address seems on R2, a downstream router.
R2#present ip route ospf
O E2 sixteen.0.0.0/6 [110/twenty] by means of 172.twelve.123.one, 00:00:05, Serial0
Let’s return to R1 and examine its OSPF table.
R1#present ip route ospf
O sixteen.0.0.0/six is actually a summary, 00:01:51, Null0
Where by did the null0 interface originate from, and why can it be there? Packets despatched to the null interface are dropped, and In cases like this, that’s a great factor.
Once you configure summary routes in OSPF, a path to null0 might be set up into the OSPF routing table. This can help to circumvent routing loops. Any packets destined for the routes that have been summarized could have a longer match from the routing table, as revealed down below…
C 17.0.0.0/8 is immediately related, Loopback17
C 16.0.0.0/8 is right related, Loopback16
C 19.0.0.0/8 is straight related, Loopback19
C eighteen.0.0.0/8 is specifically linked, Loopback18
O 16.0.0.0/6 is a summary, 00:01:51, Null0
.. and packets that don't match on the list of summarized routes but do match the summary route is going to be dropped.
Blocking routing loops when executing route redistribution and summarization is significant. OSPF provides us just a little assist in that regard in this situation, and 먹튀검증 as you review additional elaborate redistribution eventualities on your own technique to the CCNP and CCIE, you’ll realize that we’ll get all the assistance we could get!