CCNP / BSCI Test Tutorial: Route Summarization As well as OSPF Null Interface
CCNP Examination success, specifically to the BSCI exam, requires you understand the small print of route summarization. This skill not merely involves you have a comfort level with binary conversions, but It's important to know the way and where to use route summarization with Every unique protocol.
You even have http://www.bbc.co.uk/search?q=토토사이트 to find out the “Unwanted effects” of route summarization. With OSPF, there'll in fact be an additional interface produced at The purpose of summarization, and this catches plenty of CCNP candidates abruptly. Let’s Examine the null0 interface and how it relates to OSPF summarization.
On R1, the following networks are redistributed into OSPF, and afterwards summarized.
interface Loopback16
ip address 16.sixteen.sixteen.sixteen 255.0.0.0
interface Loopback17
ip address 17.17.seventeen.17 255.0.0.0
interface Loopback18
ip deal with 18.18.18.eighteen 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 connected subnets
R1(config-router)#summary-handle 16.0.0.0 252.0.0.0
The summary handle appears on R2, a downstream router.
R2#display ip route ospf
O E2 sixteen.0.0.0/6 [110/twenty] by means of 172.twelve.123.1, 00:00:05, Serial0
Let’s return to R1 and have a look at its OSPF table.
R1#clearly show ip route ospf
O sixteen.0.0.0/6 is really a summary, 00:01:51, Null0
In which did the null0 interface come from, and why is it there? Packets sent to your null interface are dropped, and In such a case, that’s a very good thing.
After you configure summary routes in OSPF, a route to null0 will likely be mounted into your OSPF routing table. This can help to circumvent routing loops. Any packets destined with the routes that have been summarized may have a longer match while in the routing table, as demonstrated down below…
C 17.0.0.0/eight is right linked, Loopback17
C 16.0.0.0/8 is immediately linked, Loopback16
C 19.0.0.0/8 is directly linked, Loopback19
C 18.0.0.0/eight is directly linked, Loopback18
O sixteen.0.0.0/6 is usually a summary, 00:01:51, Null0
.. and packets that don't match one of the summarized routes but do match the summary route will probably be dropped.
Stopping routing loops when carrying out route redistribution and summarization is significant. OSPF gives us a little help in that regard in this situation, and when you review more advanced redistribution situations on your own technique to the CCNP and CCIE, you’ll 먹튀검증 understand that we’ll just take all the assistance we may get!