we are using T1 point to point with DSL backup. if T1 is down, VPN is established over DSL connection by IP SLA. everything works as expected. now we are migrating to MPLS with BGP. in BGP configuration we don't have static route in order to monitor the link, there is only neighbor command. how can I setup IP SLA on this situation? which means if MPLS is down, then uses DSL to have VPN connection to HQ.
thanks a lot
Okay, according to this template, you will advertise all your directly connected and statically defined routes to your ISP. This is done so that the ISP and also the HQ are both aware of the networks on your location and can route packets to them via the MPLS cloud. Unfortunately, this does not explain whether your ISP sends you a default route via BGP or not which would slightly change the behavior. Do you know at this moment if the ISP sends you a default route via BGP?
If the ISP does send you the default route then the BGP-learned default route will have the same administrative distance as all other BGP routes, which is probably 20, as you have an external BGP peering with your ISP (your and his autonomous system numbers differ). The static default route would then need an administrative distance higher than 20 but less than 255 (the 255 means that the route is completely untrustworthy and won't be installed in the routing table).
In any case, if the ISP does not send you a default route, a different approach would need to be selected because in that case, you would always have the static default route in your routing table and by means of the redistribute static command, you would advertise the default route back to ISP which could have very unpleasant consequences