vrf in ce router

[suthomas1]

Hi,

There is a PE router running vrf instances. We want to connect a cisco 3845 or 3750 as the core device , connected to this PE and running bgp for the interconnection.

so how will the configuration be like?

thanks in advance.

[kradjesh13]

Hi,

I believe you are looking for a MP-eBGP peering sample configuration and have a look at the following attached configuration below. I have highlighted the configuration which you need to look at -

router bgp
bgp log-neighbor-changes
!
!
address-family ipv4
!
address-family ipv4 vrf
neighbor XX.XX.XX.XX remote-as
neighbor XX.XX.XX.XX description MP-eBGP Peering with PE
neighbor XX.XX.XX.XX timers XX XX --> Should be same as the PE Routers BGP timers
neighbor XX.XX.XX.XX activate
neighbor XX.XX.XX.XX soft-reconfiguration inbound

network XX.XX.XX.XX mask 255.255.xx.xx  --> N/W address to be advertised to neighbor via BGP
network XX.XX.XX.XX mask 255.255.xx.xx  --> N/W address to be advertised to neighbor via BGP

bgp router-id xx.xx.xx.xx ---> Optional and according to your design needs
no auto-summary
no synchronization
exit-address-family
!

Thanks

[suthomas1]

Thank you. the requirement is very basic. The 3750 core switch is connected to PE router .

The IP interconnection is planned to be done using bgp. the PE is  running vrf, what is the basic configuration needed on the 3750 so that  both devices communicate and users in 3750 are able to reach PE router  for further relay to internet.

[Raju Sekharan]

I assume here that your IGP is ospf and your PE is going to advertise only default-route to you via BGP

Router BGP < Your AS Number >

neighbor XX.XX.XX.XX remote-as

redistibute ospf

router ospf 1

Network statements

.....

.....

default-information originate

Instead of default-information originate, you can also redistribute BGP to OSPF. But then you need to make sure that you put a route-amp to allow only default-route so that you protect any prefix flood to your netork due to any miss-configuration 

Thank you

Raju

[suthomas1]

Thank you again.

there is no specific IGP in the core switch. it will be just a default route towards PE router and PE will point to core for internal lan segments.

does this change the configuration anyway?

[Raju Sekharan · Accepted solution]

Hi

Your core switch is going to have a default route towards the CE

Is the PE also going to use static route to route the packets to your LAN? In that case you don't need to run BGP with PE

Here is a link explainign such scenario

http://www.cisco.com/en/US/tech/tk436/tk428/technologies_configuration_example09186a00801445fb.shtml

Thank you

Raju