CCNP / BSCI Examination Tutorial: Route Summarization And The OSPF Null Interface
CCNP Test accomplishment, specially around the BSCI exam, requires you realize the main points of route summarization. This skill don't just requires that you've got a comfort and ease stage with binary conversions, but You must know how and exactly where to apply route summarization with Every single personal protocol.
You also have to understand the “Unintended effects” of route summarization. With OSPF, there will actually be an extra interface established at The purpose of summarization, and this catches plenty of CCNP candidates unexpectedly. Permit’s Have http://www.bbc.co.uk/search?q=토토사이트 a look at the null0 interface and how it pertains to OSPF summarization.
On R1, the following networks are redistributed into OSPF, then summarized.
interface Loopback16
ip tackle 16.sixteen.sixteen.sixteen 255.0.0.0
interface Loopback17
ip handle 17.17.17.seventeen 255.0.0.0
interface Loopback18
ip handle eighteen.eighteen.eighteen.18 255.0.0.0
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-tackle sixteen.0.0.0 252.0.0.0
The summary deal with appears on R2, a downstream router.
R2#show ip route ospf
O E2 16.0.0.0/six [one hundred ten/twenty] through 172.twelve.123.1, 00:00:05, Serial0
Permit’s return to R1 and take a look at its OSPF desk.
R1#demonstrate ip route ospf
O 16.0.0.0/six can be a summary, 00:01:fifty one, Null0
In which did the null0 interface originate from, and why is it there? Packets despatched for the null interface are dropped, and In such a case, that’s a great matter.
After 먹튀검증 you configure summary routes in OSPF, a route to null0 will probably be put in in to the OSPF routing table. This will help to stop routing loops. Any packets destined to the routes that were summarized will likely have a longer match within the routing table, as demonstrated underneath…
C 17.0.0.0/eight is directly linked, Loopback17
C sixteen.0.0.0/eight is instantly related, Loopback16
C 19.0.0.0/8 is directly connected, Loopback19
C eighteen.0.0.0/8 is immediately related, Loopback18
O 16.0.0.0/6 is often a summary, 00:01:fifty one, Null0
.. and packets that don't match among the summarized routes but do match the summary route might be dropped.
Stopping routing loops when executing route redistribution and summarization is significant. OSPF provides us a bit help in that regard in this example, and as you examine much more elaborate redistribution situations on your own approach to the CCNP and CCIE, you’ll know that we’ll acquire all the assistance we will get!