CCNP / BSCI Examination Tutorial: Route Summarization And also the OSPF Null Interface
CCNP Examination results, especially to the BSCI Test, requires you realize the main points of route summarization. This ability not just calls for you have a convenience amount with binary conversions, but You will need to understand how and where by to apply route summarization with each unique protocol.
You also have to be aware of the “Unintended effects” of route summarization. With OSPF, there will basically be an extra interface made at the point of summarization, which catches many CCNP candidates abruptly. Permit’s Consider the null0 interface and how it relates to OSPF summarization.
On R1, the following networks are redistributed into OSPF, and after that summarized.
interface Loopback16
ip deal with sixteen.sixteen.16.sixteen 255.0.0.0
interface Loopback17
ip handle 17.seventeen.17.seventeen 255.0.0.0
interface Loopback18
ip handle 18.eighteen.eighteen.18 255.0.0.0
interface Loopback19
ip deal with 19.19.19.19 255.0.0.0
R1(config)#router ospf one
R1(config-router)#redistribute connected subnets
R1(config-router)#summary-handle sixteen.0.0.0 252.0.0.0
The summary address seems on R2, a downstream router.
R2#present ip route ospf
O E2 16.0.0.0/six [110/twenty] through 172.twelve.123.1, 00:00:05, Serial0
Allow’s go back to R1 and have a look at its OSPF table.
R1#demonstrate ip route ospf
O 16.0.0.0/six is usually a summary, 00:01:51, Null0
Wherever did the null0 interface originate from, and why could it be there? Packets despatched on the null interface are dropped, and In such cases, that’s an https://en.search.wordpress.com/?src=organic&q=토토사이트 excellent factor.
When you configure summary routes in OSPF, a path to null0 will likely be installed into your OSPF routing desk. This assists to prevent routing loops. Any packets destined to the routes which have been summarized may have a longer match during the routing table, as demonstrated underneath…
C 17.0.0.0/8 is right linked, Loopback17
C 16.0.0.0/8 is specifically related, Loopback16
C 19.0.0.0/eight is directly connected, Loopback19
C eighteen.0.0.0/eight is directly related, Loopback18
O 16.0.0.0/six is often a summary, 00:01:fifty one, Null0
.. and packets that do not match one of several summarized routes but do match the summary route are going to be dropped.
Avoiding routing loops when undertaking 토토 route redistribution and summarization is vital. OSPF gives us a little help in that regard in this situation, and when you research additional sophisticated redistribution eventualities with your method to the CCNP and CCIE, you’ll realize that we’ll choose all the assistance we will get!