CCNP / BSCI Examination Tutorial: Route Summarization And The OSPF Null Interface
CCNP Examination achievement, significantly to the BSCI Test, needs you fully grasp the details of route summarization. This talent not just requires that you have a convenience amount with binary conversions, but You should understand how and wherever to apply route summarization with Each individual personal protocol.
You also have to find out the “side https://www.washingtonpost.com/newssearch/?query=토토사이트 effects” of route summarization. With OSPF, there will really be an extra interface created at The purpose of summarization, and this catches loads of CCNP candidates without warning. Permit’s Look into the null0 interface and how it pertains to OSPF summarization.
On R1, the next networks are redistributed into OSPF, then summarized.
interface Loopback16
ip deal with 16.sixteen.sixteen.16 255.0.0.0
interface Loopback17
ip tackle 먹튀검증 seventeen.17.seventeen.17 255.0.0.0
interface Loopback18
ip handle 18.18.eighteen.eighteen 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 related subnets
R1(config-router)#summary-handle 16.0.0.0 252.0.0.0
The summary tackle appears on R2, a downstream router.
R2#demonstrate ip route ospf
O E2 16.0.0.0/six [a hundred and ten/twenty] by means of 172.12.123.one, 00:00:05, Serial0
Let’s go back to R1 and have a look at its OSPF desk.
R1#present ip route ospf
O sixteen.0.0.0/6 is actually a summary, 00:01:51, Null0
Where by did the null0 interface come from, and why is it there? Packets despatched to your null interface are dropped, and in this case, that’s an excellent detail.
Whenever you configure summary routes in OSPF, a route to null0 will probably be put in to the OSPF routing desk. This assists to prevent routing loops. Any packets destined with the routes that were summarized may have a longer match inside the routing desk, as shown down below…
C 17.0.0.0/8 is specifically related, Loopback17
C sixteen.0.0.0/8 is specifically connected, Loopback16
C 19.0.0.0/eight is right connected, Loopback19
C 18.0.0.0/eight is instantly related, Loopback18
O 16.0.0.0/six is usually a summary, 00:01:fifty one, Null0
.. and packets that don't match among the summarized routes but do match the summary route will be dropped.
Protecting against routing loops when executing route redistribution and summarization is vital. OSPF offers us just a little help in that regard in this example, and while you analyze more elaborate redistribution scenarios in your strategy to the CCNP and CCIE, you’ll understand that we’ll get all the help we will get!