CCNP / BSCI Test Tutorial: Route Summarization Along with the OSPF Null Interface
CCNP Test accomplishment, particularly around the BSCI exam, needs you fully grasp the details of route summarization. This talent don't just demands that you've got a comfort degree with binary conversions, but You need to know how and wherever to use route summarization with Every single unique protocol.
You even have to be aware of the “Uncomfortable side effects” of route summarization. With OSPF, there'll really be an extra interface produced at The purpose of summarization, and this catches a great deal of CCNP candidates abruptly. Allow’s Check out the null0 interface And just how it pertains to OSPF summarization.
On R1, the next networks are redistributed into OSPF, and then summarized.
interface Loopback16
ip tackle 16.sixteen.sixteen.16 255.0.0.0
interface Loopback17
ip handle seventeen.17.seventeen.seventeen 255.0.0.0
interface Loopback18
ip tackle 18.18.eighteen.eighteen 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 linked subnets
R1(config-router)#summary-address sixteen.0.0.0 252.0.0.0
The summary deal with seems on R2, a http://query.nytimes.com/search/sitesearch/?action=click&contentCollection®ion=TopBar&WT.nav=searchWidget&module=SearchSubmit&pgtype=Homepage#/토토사이트 downstream router.
R2#clearly show ip route ospf
O E2 16.0.0.0/6 [a hundred and ten/20] via 172.twelve.123.1, 00:00:05, Serial0
Permit’s return to R1 and check out its OSPF table.
R1#show ip route ospf
O 16.0.0.0/six is a summary, 00:01:fifty one, Null0
Where by did the null0 interface originate from, and why is it there? Packets sent for the null interface are dropped, and In such cases, that’s a good detail.
If you configure summary routes in OSPF, a route to null0 is going to be set up into the OSPF routing desk. This can help to avoid routing loops. Any packets destined for that routes which have been summarized could have an extended match from the routing desk, as revealed beneath…
C seventeen.0.0.0/8 is instantly linked, Loopback17
C 16.0.0.0/eight is straight related, Loopback16
C 19.0.0.0/eight is instantly connected, Loopback19
C eighteen.0.0.0/8 is right linked, Loopback18
O 16.0.0.0/6 is often a summary, 00:01:fifty one, Null0
.. and packets that don't match one of many summarized routes but do match the summary route are going to be dropped.
Avoiding routing loops when performing route redistribution and 토토 summarization is vital. OSPF offers us just a little help in that regard in this situation, and while you analyze a lot more complex redistribution eventualities on your own solution to the CCNP and CCIE, you’ll know that we’ll get all the assistance we could possibly get!