[j-nsp] OSPF reference-bandwidth 1T

[Saku Ytti]

On Thu, 17 Jan 2019 at 17:49, Thomas Bellman <bellman at nsc.liu.se> wrote:

> Would you advise avoiding bandwidth-based metrics in e.g. datacenter
> or campus networks as well?

I see no point at all in bandwidth based metrics. If we are talking
about simple networks, then probably actual SPT out-come would be same
by having same metric in every link (i.e. make distance vector out of
your link-state, (essentially what RFC7938 topologies would be). This
would be simplest possible metric design.

> (I am myself running a mostly DC network, with a little bit of campus
> network on the side, and we use bandwidth-based metrics in our OSPF.
> But we have standardized on using 3 Tbit/s as our "reference bandwidth",
> and Junos doesn't allow us to set that, so we set explicit metrics.)

And you have shorter paths with inferior bandwidth which you do not
want to use, you'll rather take 9x10GE links than 1xGE to reach the
destination? It boggles my mind which network has _common case_ where
bandwidth is most indicative of best SPT.

-- 
  ++ytti