Routing issue

[M.Sultan]

I have network 10.0.0.0 10.64.0.0 10.128.0.0 10.192.0.0 with subnet of 255.192.0.0 in Area 93 which is summarized on R1

Other networks 10.32.0.0 10.64.0.0 10.96.0.0 10.128.0.0 with subnet of 255.224.0.0 not summarized on R7

Now! when i ping 10.63.255.254 which is in R2 in area 93 it doesn't ping.

we know by default router forward the traffic based on longest prefix match, here the routes from Area 10 is not summarized and still has the longest prefix, while the routes from area 10 is summarized and advertised with prefix of 255.0.0.0

in your opinion what can cause the problem ? what is the solution ?

[MHM Cisco World]

From where to where you ping and success and failed'

I need to see RIB of routers in both case.

[M.Sultan]

from R8, all routes are included in R8.

[MHM Cisco World]

But ping is two way' are R2 know the way back to R8 ?

Use traceroute to find where ping stop

[Harold Ritter]

Hi @M.Sultan ,

> Other networks 10.32.0.0 10.64.0.0 10.96.0.0 10.128.0.0 with subnet of 255.224.0.0 not summarized on R7

It is normal for traffic from R8 to follow the longest prefix match for 10.63.255.254 towards area 50, as you summarize on R1, but not on R7.

Regards,

[M.Sultan]

I summarized routes from area 93 on R1 toward Area 0, all routers in all areas has the summarized with prefix of 255.0.0.0.

The routes within the same range not summarized and has its own full prefix like 255.224.0.0.

when i ping/trace from R8 the interface which is in area 93 R2 10.63.255.254, but the traffic goes through R7 toward R20 where the routes are with longest prefix match even i trace whole network intend to reach R2 networks but it flows to R20.

This is the problem in network, how we can solve it ? i'm looking for solution.

[Harold Ritter]

Hi @M.Sultan ,

From what you told us so far, R1 advertises 10.0.0.0/8 in area 0 and R7 advertises 10.32.0.0/11 in area 0. The more specific route through R7 will be used to reach 10.63.255.254. If you want to be able to ping 10.63.255.254 (R2), you need to advertise a more specific route from area 93.

Regards,

[MHM Cisco World]

there is two 10.0.0.0 subnet here one summary and other NO.
here you traceroute 10.0.0.0 so the R8
can you do 

show ip route 10.0.0.0

longest <<-in R8 check which path is select here and share here 

[Harold Ritter]

Hi @MHM Cisco World ,

According to the diagram, area 50 is connected to area 0 via a virtual link through area 10.

Regards,

[MHM Cisco World]

thanks I SEE it it end in 7.7.7.7 (R7)

[MHM Cisco World · Accepted solution]

your tracroute show  that the path is GREEN (as show in photo I attach)
but the traceroute you use is 10.0.0.0 <<- this network not host IP that why the ping and traceroute failed 
I make similar lab below and the result as your 
traceroute to 5.0.0.0 is failed but to 5.0.0.0.1 success 

[M.Sultan]

@MHM Cisco World  refer to the diagram and offer a solution.