[ixpmanager] Shared Port

[Barry O'Donovan]

Nick Hilliard wrote on 22/12/2020 22:37:
> We solved this by using multi-port ethernet cards and using dedicated 
> ports for each service.  It's not efficient but it does work.

And where we couldn't, we just created fake ports on existing switches. 
Yuck.

There's a piece of work to do here to try and facilitate this and 
fallback to, e.g., sflow data for those 'port' graphs. This isn't really 
high on the to-do list though.

  - Barry