[Bridge] Re: Reset of setpathcost after link comes back up

[Vassil Panayotov]

On 8/18/07, Srinivas M.A. <srinivas.aji at gmail.com> wrote:
> >
> > > IMO this is the desired behaviour - the port path cost is recalculated
> > > every time when link state change is detected, probably to accommodate
> > > to possible link speed change.
> >
> > Yup.
> >
>
> I think that if the port path cost has been adminstratively set, it
> should not be recalculated when the link speed changes. There is a
> patch in the February archives which is supposed to fix this, but it
> doesn't seem to have made it upstream yet.
>
> The patch:
> [Bridge] [PATCH 3/4] bridge: make path cost setting persistent
> https://lists.linux-foundation.org/pipermail/bridge/2007-February/005265.html
>

I guess you are right. IIRC in the root port selection process the
path cost is the second evaluated parameter(only the root bridge ID is
more significant), so maybe there is topologies that are better tuned
using the path cost instead of bridge/port priority.