[FROG] OSPF Fast Convergence (RFC6976)?

[James Bensley]

On 14 August 2018 at 12:56, Timo Schöler <timo at kroenchenstadt.de> wrote:
> Hi all,
>
> I came across
>
> ``Framework for Loop-Free Convergence – Using the Ordered Forwarding
> Information Base (oFIB) Approach'' [0]
>
> which may be a phantastic remedy to a problem that occurs from time to
> time in a network I maintain: Even restarting a single OSPF process (on
> a group of about 20 routers in that area) causes trouble in
> forwarding/routing of 60.000+ TCP streams that traverse that area.
>
> (EIGRP is said to be immune against that because of explicit termination
> of the diffusing computations.)
>
> AFAICS it's not implemented yet in any free routing suite – are there
> any plans of doing so (in FRR)?
>
> Best regards,
>
> Timo
>
> [0] – https://tools.ietf.org/html/rfc6976

Hi Timo,

Have you seen this darft?

https://tools.ietf.org/html/draft-ietf-rtgwg-backoff-algo-10

It discusses a simpler method to achieve similar results. RFC6979
isn't implemented anywhere as far as I know, even by Cisco for example
who co-wrote that RFC. I think in reality it wasn't the best approach.

If you use a heirarchical FIB then after detecting a failure the
traffic loss from reconvergence alone can be as low as a few
milliseconds.

Cheers,
James.