Hi, you've written most routers are dual-attached, so the concern mostly is failure detection and not re-establishment of a neighbor I think. If you go into debounce or carrier-delay you'll raise the convergence time as a link failure will be ignored for a short time before processes are notified.
OSPF should immediately react on an link-down event, so I'd try to speed it up this way. If you use 2 separate SVI for the 2 connections and each VLAN has only 1 port it is allowed in (either a single access port or exactly 1 trunk port) the SVI should go down along with that single port. Playing around the timers I keep for last resort - as there's always the risk to de-stabilize the network seriously (I've seen people trying to get the last second out of a protocol resulting in occasional burn-downs far too often). regards, Marcus > -----Ursprüngliche Nachricht----- > Von: [email protected] > [mailto:[email protected]] Im Auftrag von Phil Mayers > Gesendet: Montag, 16. März 2009 17:45 > An: [email protected] > Betreff: [c-nsp] Fast IGP on 6500 & gigE > > All, > > Given a mix of 6748-SFP, 6704 and 6716 linecards, with SXI > software, and > OSPF over SVIs, what are people successfully using to speed > up link loss > and subsequent IGP convergence? > > Our config broadly looks like: > > int Vlan38xx > description p2p to another router > ip address 192.168.0.2 255.255.255.254 > ip ospf network point-to-point > > int Te1/1 > switchport > switchport mode trunk > switchport trunk native vlan 38xx > > router ospf 1 > ispf > nsf > network 192.168.0.0 0.0.0.255 > > ....and then the various LDP & BGP configs on top. I'm > assuming I want > some combination of: > > 1. debounce / carrier-delay (what's the difference) on the gigE > 2. IP event dampening on the SVI > 3. faster timers on the SFP process; possibly as a > conservative start: > > timers throttle spf 10 100 5000 > timers throttle lsa all 10 100 5000 > timers lsa arrival 80 > > The idea is that most routers are dual-attached, so I just want to > underlying IGP to converge quickly. I'll tackle the LDP and > BGP later... > > I'm not able to use BFD (since it doesn't work on SVIs under SXI) and > I'm only worried about physical link-down - we don't have any weird > layer2 between routers except in a few out-of-the way places, > and they > can just suffer. > > I realise some of these answers are "it depends" on the size of your > network; there are ~25 routers participating in the OSPF, all > reasonably > recent and modern, it's a single area 0 design, and it has ~58 p2p & > loopbacks (via router LSAs) another 18 E2 routes. > > It seems to take ~6msec for an OSPF adjacency to form between two > routers, almost all of which is in INIT->2WAY so I'm guessing SPF is > going to be pretty quick. > > Suggestions welcome, although "ask Cisco to tell you" is less > helpful; > I'd like to have some independent understanding of how we > arrived at the > numbers, and be able to repeat the process in future ;o) > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ > _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
