CCNP / BSCI Examination Tutorial: Route Summarization Along with the OSPF Null Interface
CCNP Examination success, specially to the BSCI Test, requires you recognize the main points of route summarization. This skill not only involves you have a comfort and ease degree with binary conversions, but You will need to understand how and wherever to use route summarization with Every specific protocol.
You also have to understand the “Unintended effects” of route summarization. With OSPF, there'll actually be an extra interface established at The purpose of summarization, which catches a great deal of CCNP candidates unexpectedly. Let’s 먹튀 Check out the null0 interface And just how it pertains to OSPF summarization.
On R1, the next networks are redistributed into OSPF, after which you can summarized.
interface Loopback16
ip handle sixteen.16.16.16 255.0.0.0
interface Loopback17
ip tackle 17.seventeen.seventeen.seventeen 255.0.0.0
interface Loopback18
ip address eighteen.18.eighteen.18 255.0.0.0
interface Loopback19
ip address 19.19.19.19 255.0.0.0
R1(config)#router ospf one
R1(config-router)#redistribute connected subnets
R1(config-router)#summary-deal with 16.0.0.0 252.0.0.0
The summary handle seems on R2, a downstream router.
R2#exhibit ip route ospf
O E2 sixteen.0.0.0/six [110/twenty] by means of 172.twelve.123.one, 00:00:05, Serial0
Enable’s go back to R1 and take a look at its OSPF table.
R1#exhibit ip route ospf
O 16.0.0.0/six can be a summary, 00:01:fifty one, Null0
Wherever did the null0 interface originate from, and why could it be there? Packets sent towards the null interface are dropped, and In such cases, that’s a great point.
After you configure summary routes in OSPF, a route to null0 are going to be put in to the OSPF routing desk. This assists to prevent routing loops. Any packets destined for your routes that have been summarized could have a longer match within the routing desk, as demonstrated down below…
C 17.0.0.0/8 is specifically connected, Loopback17
C sixteen.0.0.0/eight is instantly connected, Loopback16
C 19.0.0.0/8 is immediately linked, Loopback19
C eighteen.0.0.0/8 is immediately linked, 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 will probably be dropped.
Avoiding routing loops when undertaking route redistribution and summarization is significant. OSPF provides us just a little help in that regard in this case, and while you review additional complex redistribution situations on your method to the CCNP and CCIE, you’ll know that we’ll choose all the assistance we can get!