What types of routers are you currently using? On Sat, Nov 21, 2015 at 7:44 AM, Baldur Norddahl <baldur.nordd...@gmail.com> wrote:
> Hi > > I got a network with two routers and two IP transit providers, each with > the full BGP table. Router A is connected to provider A and router B to > provider B. We use MPLS with a L3VPN with a VRF called "internet". > Everything happens inside that VRF. > > Now if I interrupt one of the IP transit circuits, the routers will take > several minutes to remove the now bad routes and move everything to the > remaining transit provider. This is very noticeable to the customers. I am > looking into ways to improve that. > > I added a default static route 0.0.0.0 to provider A on router A and did > the same to provider B on router B. This is supposed to be a trick that > allows the network to move packets before everything is fully converged. > Traffic might not leave the most optimal link, but it will be delivered. > > Say I take down the provider A link on router A. As I understand it, the > hardware will notice this right away and stop using the routes to provider > A. Router A might know about the default route on router B and send the > traffic to router B. However this is not much help, because on router B > there is no link that is down, so the hardware is unaware until the BGP > process is done updating the hardware tables. Which apparently can take > several minutes. > > My routers also have multipath support, but I am unsure if that is going to > be of any help. > > Anyone got any tricks or pointers to what can be done to optimize the > downtime in case of a IP transit link failure? Or the related case of one > my routers going down or the link between them going down (the traffic > would go a non-direct way instead if the direct link is down). > > Thanks, > > Baldur >