[quagga-dev 8915] Re: [PATCH] Zebra rib/fib to be in sinc with kernel routing table

Joakim Tjernlund joakim.tjernlund at transmode.se
Fri Oct 21 14:36:03 BST 2011


>
> 2011/10/20 Stephen Hemminger <shemminger at vyatta.com>:
> > The concept is good, in fact Vyatta added a patch to do this to Quagga
> > which I keep meaning to revise and submit. But your patch is not enough
> > to successfully manage kernel routes.  There were another of other
> > related issues that need to be addressed:
> >  1. When this was brought up in the past, there were users who did
> >     not think this was what they wanted. In our version, the management
> >     of connected routes is optional.
> >
> >  2. In order to delete routes successfully on Linux, more state is needed.
> >     Otherwise when interface bounces you will see duplicate entries in
> >     the FIB. At a minimum this includes scope and metric which have
> >     to be tracked.
> >
>
> When interface bounces, you think that kernel routes aren't deleted
> from kernel table?
>
> >  3. You have to deal with the case where link detect is enabled.
> >     Normally (at least on Linux), IPv4 routes are maintained when carrier
> >     is lost. If linkdetect is enabled in Quagga, then the RIB has
> >     to actively delete those routes.
> >
>
> I'm just started hacking Quagga, so I have to ask you this.
> If link detection is enabled in Quagga, when carrier is lost for the
> interface, all the routes that where connected to that interface are
> deleted from quagga's RIB, but they are not deleted from kernel
> tables? If this is the case,
> to me, that seems like a problem.
> Also when carrier goes up for the interface, is kernel going to
> announce the creating of the routes that were maintained when carrier
> was lost? Or is he going to make any announce for those routes(that
> they gone up)?
>
> BR
> Igor Maravić

BTW, if you are going to hack route delete code in Q you need at least this patch:
  http://lists.quagga.net/pipermail/quagga-dev/2009-January/007704.html
People with route delete problems has found that this patch cure their problems.

 Jocke




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