Re: Route map problem

pratik_193 · ‎03-03-2011

HI All,

I am attaching my current network topology,

My problem is that i am having mpls & p2p link terminated on the 7206 router left side of diagram.

now my problem is if i apply PBR on this 7206 router & tracert any host which are on right side of the diagram, it drops on IP 10.1.1.1..ideally it should go to my Core switch on right of the diagam.

Please help me on this ASAP.

Thanks

Pratik

andrew.prince · ‎03-03-2011

PBR only works in 1 direction and it perfomed per hop. Your issue will probably be on the right side routing for the return patch, check that.

HTH>

pratik_193 · ‎03-03-2011

HI andrew,

I do have a static route entry for the subnet it is dropping on 10.1.1.1

ip route 172.29.0.0 255.255.248.0 172.29.7.1
ip route 172.29.5.0 255.255.255.128 172.29.7.1
ip route 172.29.5.128 255.255.255.128 172.29.7.1
ip route 172.29.7.0 255.255.255.128 172.29.0.4
ip route 172.29.64.0 255.255.248.0 172.29.7.1

also i do not have any ACL on this router

can u pls help me out on this?

Thanks

Pratik

andrew.prince · ‎03-03-2011

post the config of bpth 7206 routers.

pratik_193 · ‎03-03-2011

Hi andrew,

here is the config...

ps:- as the pbr was not working & was dropping 10.1.1.1, we have removed the pbr config from both the config..

andrew.prince · ‎03-03-2011

Post the output of the traceroute you think the PBR is not working for

pratik_193 · ‎03-03-2011

Hi Andrew,

PFA the tracert to 172.29.0.1 from the right hand side router

192.168.4.20
10.1.1.2
10.1.1.1
drops from here

Also there is BGP configured on the right hand side router..which is having

network 172.29.0.0 mask 255.255.248.0 -- - destination learning via BGP also.
network 172.29.5.0 mask 255.255.255.128
network 172.29.5.128 mask 255.255.255.128
network 172.29.64.0 mask 255.255.248.0

will this be the cause of issue??

Kishore Chennupati · ‎03-03-2011

Hi Pratik,

Just going by your diagram , allow me to suggest a pointers.

1. If you are trying to reach somethig on the L3 switch on the right hand side you need to have a route back to the source.

For eg: you are sending a packet from 192.168.1.3 and using it as the source IP and lets assume 4.4.4.4 as destination which is on the layer 3 switch on the right hand side.

Now, you are using PBR on the LAN interface 192.168.4.20 saying to use 10.1.1.1 as next hop for any packet that comes with a source of 192.1681.3.

Now the packet traverses and reaches 10.1.1.1 and then if 10.1.1.1 has a route for 4.4.4.4 it will forward the packet to it. Now, as we assumed 4.4.4.4 is on L3 switch and gets it.

Now it has to return the packet to the source which is 192.168.1.3. The L3 switch on the right looks up its routing table to see if there is route back to it. If there is then it will forward it to its next-hop. The nex-hop can be via the MPLS or static via 7206 on the right hand side. If it learns via the MPLS cloud means that the routing is assymetrical. but lets not worry about that. The routing will still work

However, this switch is learning this from somewhere else then it creates black holes etc.

Now if it doesnt have a route back to the source, then where does it send its default route to?

If you can ask yourself questinos like this , I guess it makes the routing very easy.

I didnt go thru your configs but reading your problem, i thought i will give u the idea rather than just the solution

HTH

Regards,

Kishore

pratik_193 · ‎03-03-2011

Hi Kishore,

Thanks for your input.

My destination will be 172.29.0.X, 172.29.5.x, 172.29.64.x which is on L3 on right side.

now my criteria on left side router will be if source is 192.168.1.x & destination is 172.29.0.X, 172.29.5.x, 172.29.64.x it should go via P2P link.

When i apply PBR on left side router it does reach on right side routers P2P interface IP & stucks there.

I am attaching my static routes/ BGP routes here.

Router on L3 on right side

ip route 192.168.1.0 255.255.255.0 172.29.7.11 // this is my 2821 router on which MPLS is there

ip route 192.168.4.0 255.255.255.0 172.29.7.11 // this is my 2821 router on which MPLS is there

ip route 192.168.5.0 255.255.255.0 172.29.7.11 // this is my 2821 router on which MPLS is there

static Routes on right side router

ip route 172.29.0.0 255.255.248.0 172.29.7.1

ip route 172.29.5.0 255.255.255.128 172.29.7.1

ip route 172.29.5.128 255.255.255.128 172.29.7.1

ip route 172.29.7.0 255.255.255.128 172.29.0.4

ip route 172.29.64.0 255.255.248.0 172.29.7.1

ip route 172.29.72.0 255.255.255.0 172.29.7.1

ip route 192.168.1.0 255.255.255.0 10.1.1.2

ip route 192.168.4.0 255.255.255.0 10.1.1.2

BGP routes on right side router

router bgp 65111

no synchronization

bgp log-neighbor-changes

network 10.10.1.0 mask 255.255.255.0

network 10.10.10.0 mask 255.255.255.248

network 10.32.138.0 mask 255.255.254.0

network 10.32.163.0 mask 255.255.255.0

network 10.70.238.51 mask 255.255.255.255

network 10.72.176.0 mask 255.255.255.0

network 115.113.143.0 mask 255.255.255.0

network 172.29.0.0 mask 255.255.248.0

network 172.29.5.0 mask 255.255.255.128

network 172.29.5.128 mask 255.255.255.128

network 172.29.64.0 mask 255.255.248.0

network 172.29.72.0 mask 255.255.255.0

Static routes on left side router

ip route 10.32.138.0 255.255.255.0 10.209.64.81

ip route 10.32.163.0 255.255.255.0 10.209.64.81

ip route 10.72.176.0 255.255.255.0 10.209.64.81

ip route 192.168.1.0 255.255.255.0 192.168.5.21

BGP routes on left side router

network 10.209.64.80 mask 255.255.255.240

network 192.168.5.0

do you see any routes problem here??

Thanks

Pratik