[Nml-wg] Ports with multiple connections?

[Freek Dijkstra]

Jeroen van der Ham wrote:

> - Describe a single port with two links attached to it.
> This means breaks the assumption that a port can have at most one 
> bi-directional link attached to it.
> 
> - Describe a single port with two virtual ports each with its separate link.
> This breaks the assumption that a port is always connected by a Link 
> (either a cross-connect or an external link), and we introduce a new 
> concept of a virtual port. Are there other cases that would warrant this 
> introduction?
> 
> - Describe a single port that is connected to a "virtual" node where the 
> connection is split into two.
> This makes the description more complex, and also seems to allow a 
> direct connection between the two inter-domain connections without using 
> the original port.
> 
> Any other ideas?

I propose to describe at at two layers:
- one port at the layer below Ethernet (physical link, if you will)
which is connected to single a port in another domain.
 plus
- two ports at the VLAN layer, each describing a logical connection on
top of the underlying layer.
and an adaptation to describe the relations between the two (sub)layers.

This is how NDL is doing things, and it works pretty good.

Regards,
Freek Dijkstra