Latency based path selection

[Martin Kraus]

On Fri, Mar 01, 2013 at 09:07:56AM +0100, JLP wrote:
> Le 01.03.2013 00:09, Matthew Walster a écrit :
> >On 28 February 2013 23:06, Ryan Whelan <rcwhelan at gmail.com> wrote:
> >
> >>Is it possible to make route selection based on path latency?
> >>(or even
> >>delegate path selection to an external app/program/api?)
> >>[...] 
> >
> >>Any input / suggestions would be greatly appreciated!
> >
> >This might sound a little too obvious, but why not just set the
> >metric of the link to the number of micro/milliseconds measured across
> >it?
> 
> Because :
> 1/ that is not an automatic process
> 2/ you can't do real time adaptation to the latency

That would cause the routing protocol to flap constantly because as you move
to a low latency link the traffic moves as well so it becomes a high latency link,
while the previous link will get less traffic therefore it will have a lower
latency and opsf would flap again. 

cisco eigrp has a possibility to include load of the interface in the path
selection but cisco themselves don't recommend it's use. also eigrp means an
all cisco network.

mk