OSPF and HSRP

[anitachoi3]

Hi expert,

We would like to mix the OSPF and HSRP to provide a better service to custemers. The solution is following:

There are two uplink routers, R1 and R2. Each uplink router connects to one distribution layer router (R3 and R4). Below is the configuration for your reference.

Is it possible to build a "ospf nei" between two floating ip ONLY (192.168.1.1 and 192.168.1.4)? there is no "ospf nei" between the direct connection of each router. how to config it to achieve this approach?

There is only one FIB. If one of uplink routers is failure, the converging time should be very fast (depend on the HSRP). It would be less service impact on user. is it correct?

R1

!

interface GE 0/1

desc to R3 GE 0/1

ip address 192.168.1.2 255.255.255.248

standby 1 preempt

standby 1 ip 192.168.1.1

standby 1 priority 95

!

router ospf 20

network 172.16.1.0 0.0.0.255 area 0

!

R2

!

interface GE 0/1

desc to R4 GE 0/1

ip address 192.168.1.3 255.255.255.248

standby 1 preempt

standby 1 ip 192.168.1.1

standby 1 priority 105

!

router ospf 20

network 172.16.2.0 0.0.0.255 area 0

!

R3

!

interface GE 0/1

desc to R3 GE 0/1

ip address 192.168.1.5 255.255.255.248

standby 1 preempt

standby 1 ip 192.168.1.4

standby 1 priority 95

!

router ospf 20

network 172.16.3.0 0.0.0.255 area 0

!

R4

!

interface GE 0/1

desc to R4 GE 0/1

ip address 192.168.1.6 255.255.255.248

standby 1 preempt

standby 1 ip 192.168.1.4

standby 1 priority 105

!

router ospf 20

network 172.16.4.0 0.0.0.255 area 0

!

rdge

Anita

[E31qinhaijun]

hello

      You should announce 192.168.1.0 255.255.255.248 in every router

[anitachoi3]

Hi,

I try to add the ip segment (192.168.1.0/29), the client side router can establish two nei. In R3, there are two nei (R1 and R2). The opposit nei IP is 192.168.1.2 and 192.168.1.3. It cannot build nei between two floating IP addresses.

Any idea or advice?

Rdge

Anita

[Giuseppe Larosa]

Hello Anita,

I would recommend to try to use ways to improve OSPF convergence instead of adding HSRP to the picture.

There are two ways to do this:

a) use hold-timer 1 second and with sub-second hello timer, this uses the command hello-multiplier at interface level

see

http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_ospf/command/ospf-a1.html#wp2917383021

b) use of IP fast convergence using BFD (Bidirectional Forwarding Detection), but this may be unsupported on your devices as the feature has been introduced in service provider environments.

http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_bfd/configuration/15-mt/irb-bi-fwd-det.html

I agree with the other poster that your OSPF configuration doesn't look like complete, as in order to create OSPF adjacencies you need to add a network ... area 0 statement for the IP subnets between R1-R3 and R2-R4.

Hope to help

Giuseppe

[anitachoi3]

Hi Giuseppe,

Yes, the option "a" would be one of solution to achieve the purpose.

Please see if there is any possible and feasible alternatives.

rdge

Anita