Would be helpful if you let us know what platform you're running on. Assuming a Cisco, make sure next-hop-tracking not disabled (enabled by default on modern IOS), then at "BGP Prefix Independent Convergence", so your BGP process isn't walking the entire RIB to see which next-hops it needs to change.
Greg Foletta g...@foletta.org +61 408 199 630 On 23 November 2015 at 05:12, Colton Conor <colton.co...@gmail.com> wrote: > 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 > > >
