CCNP / BSCI Test Tutorial: Route Summarization As well as the OSPF Null Interface
CCNP Examination results, notably within the BSCI Examination, calls for you realize the details of route summarization. This ability don't just needs that you have a comfort level with binary conversions, but It's important to understand http://query.nytimes.com/search/sitesearch/?action=click&contentCollection®ion=TopBar&WT.nav=searchWidget&module=SearchSubmit&pgtype=Homepage#/토토사이트 how and where to apply route summarization with Just about every specific protocol.
You even have to find out the “Negative effects” of route summarization. With OSPF, there will in fact be an extra interface designed at The purpose of summarization, which catches many CCNP candidates unexpectedly. Enable’s take a look at the null0 interface And the way it pertains to OSPF summarization.
On R1, the following networks are redistributed into OSPF, and afterwards summarized.
interface Loopback16
ip handle sixteen.16.sixteen.sixteen 255.0.0.0
interface Loopback17
ip tackle seventeen.17.17.17 255.0.0.0
interface Loopback18
ip tackle 18.18.18.eighteen 255.0.0.0
interface Loopback19
ip handle 19.19.19.19 255.0.0.0
R1(config)#router ospf 1
R1(config-router)#redistribute related subnets
R1(config-router)#summary-address 16.0.0.0 252.0.0.0
The summary deal with seems on R2, a downstream router.
R2#show ip route ospf
O E2 sixteen.0.0.0/six [one hundred ten/twenty] by means of 172.12.123.1, 00:00:05, Serial0
Permit’s go back to R1 and have a look at its OSPF desk.
R1#show ip route ospf
O sixteen.0.0.0/six is usually a summary, 00:01:fifty one, Null0
Where by did the null0 interface originate from, and why is it there? Packets despatched to the null interface are dropped, and In such a case, that’s a superb point.
Any time you configure summary routes in OSPF, a path to null0 will probably be put in in the OSPF routing desk. This allows to stop routing loops. Any packets destined for the routes which were summarized may have a longer match within the routing desk, as proven underneath…
C 17.0.0.0/eight is immediately related, Loopback17
C sixteen.0.0.0/eight is instantly connected, Loopback16
C 19.0.0.0/8 is specifically connected, Loopback19
C eighteen.0.0.0/8 is straight related, Loopback18
O 16.0.0.0/six is usually a summary, 00:01:51, Null0
.. and packets that don't match among the summarized routes but do 먹튀검증 match the summary route will probably be dropped.
Preventing routing loops when executing route redistribution and summarization is important. OSPF gives us a little bit help in that regard in this case, and when you review more complicated redistribution situations with your strategy to the CCNP and CCIE, you’ll understand that we’ll acquire all the assistance we could possibly get!