[quagga-users 8034] Re: Quagga / ospfv2 (version 0.99.6) - Reduceconvergence time

Gobbledegeek gobbledegeek at gmail.com
Thu Feb 15 15:29:35 GMT 2007


All
On second thoughts if the interface goes down, ospf will not try to
become DR on that segment ... pardon the confusion I created.

I guess the timers throttle is your only hope ...

Regards
Rahul

On 2/15/07, Gobbledegeek <gobbledegeek at gmail.com> wrote:
> Hi
> so  timers throttle spf 200 200 1000 did not work for you? How about
> "timers throttle spf 10 100 5000" ?
>
> There will be three sources of delays here:
>
> 1. Time to detect link failure - (do you have linik-detect
> configured?). Desktop PC's may not provide time granularity below
> 500ms or one clock tick.( RTOSes on ASICs as in cisco routers will
> ...)
>
> 2.  SPF computation time - timers throttle spf <spf-start> <spf-hold>
> <spf-max-wait> can reduce this. Other factors are number of neighbors
> to flood lsa's to, time taken to generate and propogate lsa's
>
> 3. Time to update routing tables -  depends on OS will be slow for
> desktop OSes. (tslking in milliseconds)
>
> Did you try setting the RouterDeadInterval to 2 seconds ? Since the
> Designated router on a broadcast medium will be responsible for
> generating lsa's, there will be a 2 second delay (default 5 I think)
> involved here - both will become DRs on a partitioned network ( I
> don't see a point in making RouterDeadInterval less than dead time).
> SPF will only run in both routers after a new router lsa is generated
> with Max-Age (correct me if I am  wrong, I am currently away from my
> reference library). In this case the major  bottle neck may be here.
>
> Alternatively you can try upgrading to 0.99.6 and making the ethernet
> link point-to-point (0.99.6 has a patch for correctly doing this) on
> both routers ( interface command) First try with existing version,
> (command exists but behavior may not be rfc spec - I have used
> point-to-point mode in 2005 to prevent DR/BDR election). This may help
> you achieve very short failover times together with "timers throttle
> spf" command...
>
> Regards
> Rahul Sawarkar
>
>
>
> On 2/15/07, Preben Myrvoll <PMyrvoll at oslo.westerngeco.slb.com> wrote:
> > Hi, and thanks for all your assistance:
> >
> > In my setup I already have the following params:
> >
> > ip ospf hello-interval 1
> > ip ospf dead-interval 2
> >
> >
> > I've also now tried:
> >
> > timers throttle spf 200 200 1000
> >
> > Regards
> >
> > Any other setusp/configs?
> > Preben
> >
>


-- 
Rgrds
GobbledeGeek
[Everything but Gobbledegook.. !!]


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