CCNP / BSCI Test Tutorial: Route Summarization Along with the OSPF Null 먹튀검증 Interface
CCNP Examination results, notably around the BSCI exam, needs you comprehend the details of route summarization. This ability not just needs you have a comfort stage with binary conversions, but You must know the way and wherever to use route summarization with Each individual specific protocol.
You even have to understand the “side effects” of route summarization. With OSPF, there will truly be an extra interface made at The purpose of summarization, which catches many CCNP candidates without warning. Allow’s take a look at the null0 interface And just how it pertains to OSPF summarization.
On R1, the next networks are redistributed into OSPF, and after that summarized.
interface Loopback16
ip deal with 16.16.16.sixteen 255.0.0.0
interface Loopback17
ip handle 17.seventeen.17.17 255.0.0.0
interface Loopback18
ip tackle eighteen.18.18.eighteen 255.0.0.0
interface Loopback19
ip tackle 19.19.19.19 255.0.0.0
R1(config)#router ospf 1
R1(config-router)#redistribute related subnets
R1(config-router)#summary-deal with sixteen.0.0.0 252.0.0.0
The summary address seems on R2, a downstream router.
R2#exhibit ip route ospf
O E2 sixteen.0.0.0/6 [110/twenty] by means of 172.12.123.one, 00:00:05, Serial0
Allow’s return to R1 and check out its OSPF desk.
R1#display ip route ospf
O 16.0.0.0/six can be a summary, 00:01:51, Null0
In which did the null0 interface originate from, and why can it be there? Packets sent towards the null interface are dropped, and in this case, that’s a very good matter.
Once you configure summary routes in OSPF, a path to null0 might be mounted into your OSPF routing table. This allows to prevent routing loops. Any packets destined for that routes which were summarized can have an extended match inside the routing table, as demonstrated underneath…
C 17.0.0.0/eight is instantly connected, Loopback17
C 16.0.0.0/8 is immediately related, Loopback16
C 19.0.0.0/eight is specifically related, Loopback19
C eighteen.0.0.0/8 is specifically linked, Loopback18
O sixteen.0.0.0/six is actually a summary, 00:01:51, Null0
.. and packets that don't match among the summarized routes but do match the summary route are going to be dropped.
Avoiding routing loops when executing route redistribution and summarization is significant. OSPF provides us somewhat assist in that regard in this case, and as you review more complicated redistribution scenarios on your own approach to the CCNP and CCIE, you’ll understand that we’ll acquire all the help we could get!