BGP & Static route

[louis0001]

We have a single ISP. We connect to that ISP via a 1G fibre ethernet connection into a private MPLS network. This uses BGP routing for the fibre ethernet.

We are thinking of utilising a backup connection (using VRRP) to the same ISP into the same MPLS network. However, this connection uses VDSL and the routing is static for the MPLS which will advertise the same subnets for that same location. We only want to use this as a backup (no load balancing) and this uses a different network provider and different exchange.

How do we ensure that the primary route (using BGP) takes preference over the the backup route (using static routing). For outgoing, this is taken care of using VRRP but the MPLS network routing is the part we're concerned with.
Is it just a case of using an AD of 200+ on the static route at the ISP so the BGP route (when advertised) takes preference?

[Giuseppe Larosa · Accepted solution]

Hello @louis0001 ,

>> Is it just a case of using an AD of 200+ on the static route at the ISP so the BGP route (when advertised) takes preference?

Yes, this might  be the right tool to achieve the desired behaviour on your routers.

There are some doubts however, because you have written that the backup VDSL link is provided by a different network operator.

However, it is the MPLS provider that should configure its PE nodes so that the backup path is treated as a backup path.

So in general , the MPLS provider may need to use an increased local preference like 150 (default is 100 greater value is preferred ) to give visibility of primary BGP routes over secondary routes in the whole BGP AS.

You need to talk with MPLS provider engineers and you should test the solution emulating a fault on primary and then restore to verify that everything is configured correctly and behaviour is correct in all scenarios including restore. All this has to be done in a maintenance time window.

Hope to help

Giuseppe

Hope to help

Giuseppe

[louis0001]

Yes, two different network operators that connect into our ISP provided MPLS network. I don't think this would be an issue as long as the AD etc is set correctly at the ISP end so that it prefers the BGP route. Thank you for your input.

[MHM Cisco World]

ip route prefix mask ip-address [metric-value]
As I know not all router except to change the AD, the value in end of static route is metric no AD.
BUT I see some cisco doc. mention that some ASR can change the static route AD.
the solution for your issue is PBR.
will make the set ip next hop with IP SLA.