Route manipulation OSPF

[Julio Garcia]

Could someone help achieve a bit of route manipulation on ospf.

I have attached picture of topology.

there is a destination network 10.99.99.0 /24 hanging off node: East 1

the path to destination from Host 1 is fine, it takes the best path there ;  West 1> Middle 1 > East 1

the path to destination from Host 2 is not what i want, it also takes the best path , West 2 > Middle 2 > Middle 1 > East 1

Ideally i want it to take this path;

West 2> Middle 2 > East 3 > East 2 > East 1

could someone help me achieve this without having to change interface costs etc .

Many thanks

[Giuseppe Larosa]

Hello Rob,

if all the links are in the same OSPF area the routers have full detail of topology and you cannot change SPF choice of each node only for a specific destination or even when coming from a specific host.

You would need PBR to achieve what you want for a specific source prefix / destination prefix  and you would need to apply it on Middle2 router at least.

You could use a point to point GRE tunnel from West2 to Est3 but if your multilayer switches are less then C6500 this is not a viable option as the GRE tunnel would be process switched.

OR with OSPF you should increase to 11 or more the cost of link between Middle1 and Middle2.

This is the only way with OSPF in a single area to do this. But this would mean for all destinations behind Est1 Middle2 would send traffic to East3 instead of sending it to Middle1.

This would make this link a backup link used only in case of failure of Middle1-East1 or Middle2 to East3 links.

As noted in a previous thread MPLS traffic engineering could provide the desired result but its deployment can be complex

Hope to help

Giuseppe

[Peter Paluch]

Rob,

Is this a homework of some kind or an exercise lab, or a real network? What are the limitations? What can and what cannot be used to solve this? Why do you disagree with modifying the interface costs?

Best regards,

Peter

[Lei Tian]

I guess that's a lab excerise. Static route on M2 and E3

Regards,

Lei Tian

[Julio Garcia]

thanks very much guys , sometimes i become completely dumb anf forget all routing knowledge,

lei is right static routes better than ospf and job done.

thanks v much

reason for this is that i want to transport 2 video streams multicast from the source at East 1 but over compltely diverse paths at same time to 2 different recievers, i guess the static routes will lose me redundancy on path 2, but i dont mind so much,  want to spread out the traffic.