[Nml-wg] Definitions of Topology, Domain and Network

[Freek Dijkstra]

Aaron Brown wrote:

> A question still open is the definition of "connected"? Is it a literal
> connected graph, or does it mean connected such that folks could
> actually somehow make circuits to get from any point in the graph to any
> other point (ignoring how they know that reservations and the like can
> happen)?
> 
> For example, say someone has a switch with sonet ports and ethernet
> ports and that switch connects to two other nodes, one via ethernet and
> one via sonet. Is the implication that the node connected via ethernet
> can connected to the node connected by SONET? If not, is that a
> connected graph for these purposes, or are there two separate topologies
> (the SONET one and the Ethernet one)?

Very good point. Thanks.

I'm also puzzled about the topology definition:

> - Topology: A connected graph of Network Elements
> The intended usage of this is to describe the thing that a network
> provider advertises to others as his network topology that is available
> for use.

I do not know what a "graph of Network Elements" is.

My question is the same as Aaron's: is a network with two (physically
connected) devices (a Ethernet and a SONET device) one or two graphs?

The answer presumably depends on how the (connected) Network Elements
are mapped onto a graph: as a graph representation of physical devices;
a graph representation of abstracted or logical devices; (multiple)
graphs for each logical layer?

Instead of going in loops to define the word "graph", I would suggest to
simply remove the word graph from the definition:

> - Topology: A connected set of Network Elements

Regards,
Freek