You also may want to configure 'carrier-delay msec 0' on the interface. But you will need to configure dampening on it as well. Tweaking 'timers pacing flood' under OSPF process is an option, but use it with caution. If you are using LDP, I would recommend using LDP-IGP synchronization. Do not forget to configure 'ip ospf network point-to-point' for point-to-point gig interfaces.
Leonardo. -----Mensagem original----- De: [email protected] [mailto:[email protected]] Em nome de Phil Mayers Enviada em: terça-feira, 12 de maio de 2009 14:40 Para: Walter Keen Cc: [email protected] Assunto: Re: [c-nsp] OSPF fast convergence Walter Keen wrote: > When redesigning an OSPF service provider network, (default values, with > many gig-e links). Aside from fixing link cost issues (100mbit is > treated the same as gig-e at the moment) should I look at sub-second > timers in OSPF 'ip ospf dead-timers minimal .....' Or BFD. It looks > like either would require an IOS upgrade, but I have seen lots of > discussion about bugs in BFD. This is only for core interfaces (all > cisco 7600 series). We'll be adding MPLS and iBGP on top of this after > it's completed. Common advice seems to be to make actual link-loss detection fast, in preference to using BFD. That said, I know some people use BFD. Assuming you're using LAN cards, you may want to see if you can make router links as routed rather than SVI interfaces. Though routed interfaces are implemented internally as VLANs, presentations I saw from Cisco claim that this: int G7/1 ip address ... ...will detect link-loss (much) faster than this: int Gi7/1 switchport mode access switchport access vlan 300 int Vlan300 ip address ... Also, the OSPF process/SPF timers (as opposed to hello timers) are relevant for fast convergence (rather than link-loss). I did some research recently and concluded that, with a mostly-empty OSPF table i.e. bulk of routes in BGP, the following settings were both safe, and considerably "better" than the defaults: router ospf 1 ispf nsf timers throttle spf 10 100 5000 timers throttle lsa all 10 100 5000 timers lsa arrival 80 ...again based on reading presentations from Cisco and others advice. HTH _______________________________________________ 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/
