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OSPF summary and RIPv1 question

samsam_wang
Level 1
Level 1

two questions

first

topology like this

R5--area2--R1--area0--R2--area1--R3--RIPv1--R4

between R1,R2, the netmask is /26

other parts are /24

redistribute OSPF/RIP on R3

now R4 can not ping the ip between R1 and R2 with /26

because in area 0, no ospf summary, so how to ping the ip from R4? for extended ping, the loopback0 of R4 can ping loop0 of R1, and vice-verse, but R1 can not ping R4 with standard ping.

second question for ospf virtual-link

topology like this

R1--area0--R2---area10---R3--area0---R4

do virtual-link on R2 and R3 to connect the two area0

now the qestion is

there are 3 links between R2 and R3, like 10M link, 1.544M link and 64K link, when the virtual-link is up, which link will transfer the traffice between two area0? 10M link?

Thanks

5 Replies 5

Harold Ritter
Cisco Employee
Cisco Employee

Question 1:

You could summarize the /26 in to a /24 into area 1 on R2. This way the /24 would be advertise in RIP. The other option would be to use RIPv2 instead of RIP.

Question 2:

The VL uses the best path (as selected by SPF). Assuming you use the default cost on all the links, the 10M link would carry the traffic between R2 and R3.

Hope this helps,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

Thanks for reply

It does't work to summarize /26 to /24 into area 1 or area 2.

I tried

area 1 range x.x.x.0 255.255.255.0

I tried

area 0 range x.x.x.0 255.255.255.0

and I tried

summary-address x.x.x.0 255.255.255.0

after that

on other ospf router, the mask still is /26, and on RIPv1 router, no route, so can not ping

Did you configure the "default-metric" command under the RIP configuration on R3?

Did you configure the "area 0 range x.x.x.0 255.255.255.0" command on R2?

BTW: The summary-address will only summarize routes redistributed in OSPF (externals).

Hope this helps,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

Of course, I configure "default-metric=2" under RIP

my real topology is

R1----/26 area0----R2----area1----R3--RIPv1---R5

R1----/26 area0----R4----area10---R3--RIPv1---R5

R1 use sub-interface, same subnet with R2,R4

I use "area 0 range x.x.x.0 255.255.255.0" on R2 and R4, doesn't work

I use "area 1 range x.x.x.0 255.255.255.0" on R2 and use "area 10 range x.x.x.0 255.255.255.0" on R4, doesn't work

R1 and R5 have loopback0, put them into routing protocol, R5 loop0 can ping R1 loop0, vice verse, but R5 can not ping the /26

Do I need "area ? range x.x.x.0 255.255.255.0" on R1?

Thanks

I find it really stange that the "area range" command doesn't work. What version of IOS do you run?

Can you do a "sh ip ospf" and "sh ip route" on R2.

Thanks,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México