CCNP / BSCI Examination Tutorial: Route Summarization And also the OSPF Null Interface
CCNP exam good results, specially to the BSCI Test, needs you comprehend the small print of route summarization. This ability don't just requires that you've a consolation amount with binary conversions, but You will need to understand how and the place to apply route summarization with Each and every person protocol.
You also have to understand the “Uncomfortable side effects” of route summarization. With OSPF, there will actually be an extra interface produced at The purpose of summarization, which catches plenty of CCNP candidates abruptly. Enable’s Check out the null0 interface And the way it relates to OSPF summarization.
On R1, the next networks are redistributed into OSPF, after which https://www.washingtonpost.com/newssearch/?query=토토사이트 you can summarized.
interface Loopback16
ip deal with sixteen.16.sixteen.sixteen 255.0.0.0
interface Loopback17
ip tackle 17.17.17.seventeen 255.0.0.0
interface Loopback18
ip deal with eighteen.eighteen.eighteen.18 255.0.0.0
interface Loopback19
ip address 19.19.19.19 255.0.0.0
R1(config)#router ospf 1
R1(config-router)#redistribute related subnets
R1(config-router)#summary-handle sixteen.0.0.0 252.0.0.0
The summary deal with seems on R2, a downstream router.
R2#clearly show ip route ospf
O E2 16.0.0.0/six [a hundred and ten/twenty] via 172.12.123.1, 00:00:05, Serial0
Permit’s return to R1 and look at its OSPF table.
R1#display ip route ospf
O 16.0.0.0/6 is often a summary, 00:01:fifty one, Null0
The place did the null0 interface come from, and why is it there? Packets despatched for the null interface are dropped, and in this case, that’s a good matter.
Once you configure summary routes in OSPF, a path to null0 is going to be set up to the OSPF routing table. This allows to forestall routing loops. Any packets destined for that routes that have been summarized may have an extended match while in the routing desk, as proven down below…
C 17.0.0.0/8 is right linked, Loopback17
C 16.0.0.0/eight is directly connected, Loopback16
C 19.0.0.0/8 is directly linked, Loopback19
C get more info 18.0.0.0/8 is directly linked, Loopback18
O 16.0.0.0/six is really a summary, 00:01:51, Null0
.. and packets that do not match among the list of summarized routes but do match the summary route might be dropped.
Preventing routing loops when executing route redistribution and summarization is vital. OSPF presents us somewhat help in that regard in this example, and when you study additional elaborate redistribution situations in your approach to the CCNP and CCIE, you’ll understand that we’ll get all the help we could possibly get!