CCNP / BSCI Test Tutorial: Route Summarization As well as OSPF Null Interface
CCNP Test results, specifically over the BSCI Test, requires you realize the details of route summarization. This talent not merely demands you have a ease and comfort stage with binary conversions, but It's important to understand how and where to use route summarization with Each individual specific protocol.
You also have to understand the “Uncomfortable side effects” of route summarization. With OSPF, there'll really be an additional interface produced at The purpose of summarization, and this catches lots of CCNP candidates abruptly. Permit’s Have a look at the null0 interface And exactly how it relates to OSPF summarization.
On R1, the next networks are redistributed into OSPF, after which summarized.
interface Loopback16
ip handle 16.16.sixteen.sixteen 255.0.0.0
interface Loopback17
ip tackle seventeen.seventeen.seventeen.17 255.0.0.0
interface Loopback18
ip handle eighteen.18.eighteen.18 255.0.0.0
interface Loopback19
ip deal with 19.19.19.19 255.0.0.0
R1(config)#router ospf 1
R1(config-router)#redistribute linked subnets
R1(config-router)#summary-tackle sixteen.0.0.0 252.0.0.0
The summary tackle seems on R2, a downstream router.
R2#show ip route ospf
O E2 sixteen.0.0.0/six [110/twenty] by means of 172.twelve.123.one, 00:00:05, Serial0
Allow’s return to R1 and examine its OSPF table.
R1#show ip route ospf
O sixteen.0.0.0/six is often a summary, 00:01:51, Null0
The place did the null0 interface come from, and why can it be there? Packets despatched for the null interface are dropped, and In this instance, that’s a good detail.
If you configure summary routes in OSPF, a path to null0 will be mounted in to the OSPF routing table. This aids to circumvent routing loops. Any packets destined for your routes which have been summarized could have a longer match from the routing desk, as revealed beneath…
C 17.0.0.0/8 is straight connected, Loopback17
C sixteen.0.0.0/8 is right related, Loopback16
C 19.0.0.0/eight is directly connected, Loopback19
C eighteen.0.0.0/eight 먹튀검증 is instantly related, Loopback18
O 16.0.0.0/six is really a summary, 00:01:51, Null0
.. and packets that don't match one of several 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 slightly help in that regard in this situation, and while you review far more complex redistribution eventualities with your approach to the CCNP and CCIE, you’ll realize that we’ll choose all the assistance we can get!