CCNP / BSCI Exam Tutorial: Route Summarization And also the OSPF Null Interface
CCNP exam achievement, significantly within the BSCI Examination, calls for you comprehend the main points of route summarization. This talent not merely demands that you've a consolation degree with binary conversions, but You must know the way and where by to 토토 use route summarization with each individual protocol.
You even have to learn the “side effects” of route summarization. With OSPF, there will essentially be an extra interface developed at The purpose of summarization, which catches loads of CCNP candidates abruptly. Enable’s Have a look at the null0 interface And just how it relates to OSPF summarization.
On R1, the subsequent networks are redistributed into OSPF, after which summarized.
interface Loopback16
ip handle sixteen.sixteen.sixteen.16 255.0.0.0
interface Loopback17
ip address 17.seventeen.seventeen.17 255.0.0.0
interface Loopback18
ip handle 18.18.eighteen.18 255.0.0.0
interface Loopback19
ip tackle 19.19.19.19 255.0.0.0
R1(config)#router ospf one
R1(config-router)#redistribute related subnets
R1(config-router)#summary-tackle 16.0.0.0 252.0.0.0
The summary handle seems on R2, a downstream router.
R2#show ip route ospf
O E2 16.0.0.0/six [110/20] by means of 172.12.123.1, 00:00:05, Serial0
Allow’s go back to R1 and check out its OSPF table.
R1#clearly show ip route ospf
O sixteen.0.0.0/6 is a summary, 00:01:51, Null0
In which 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 factor.
Once you configure summary routes in OSPF, a route to null0 will probably be set up into your OSPF routing desk. This will help to avoid routing loops. Any packets destined for your routes which were summarized can have a longer match in the routing table, as demonstrated under…
C seventeen.0.0.0/eight is right related, Loopback17
C 16.0.0.0/eight is right linked, Loopback16
C 19.0.0.0/eight is immediately linked, Loopback19
C 18.0.0.0/eight is right related, Loopback18
O sixteen.0.0.0/six is usually a summary, 00:01:fifty one, Null0
.. and packets that do not match one of the summarized routes but do match the summary route is going to be dropped.
Avoiding routing loops when undertaking route redistribution and summarization is vital. OSPF offers us slightly help in that regard in this example, and when you study a lot more complicated redistribution eventualities with your technique to the CCNP and CCIE, you’ll realize that we’ll consider all the help we will get!