[Nml-wg] Use case: broadcast network (single layer)

[Guy Roberts]

Freek,

This issue is actually described quite well in G.800 by distinguishing between destination forwarding and channel forwarding:

"Destination forwarding: Symbols presented at an ingress forwarding port are selectively forwarded
to zero or more egress forwarding ports. The forwarding function requires control information to
identify the output port(s) to which a communication is destined. This control information is carried
by the symbol being forwarded (commonly in the form of a destination address). The resulting
network behaviour is traditionally known as "connectionless".
Channel forwarding: All symbols on all ingress forwarding ports are forwarded to all egress
forwarding ports. No additional control information is required with the symbol. When there is a
single ingress forwarding port the forwarding relationship is equivalent to a subnetwork connection
in [ITU-T G.805]."

-----Original Message-----
From: Guy Roberts 
Sent: 10 August 2009 15:34
To: 'Freek Dijkstra'
Subject: RE: [Nml-wg] Use case: broadcast network (single layer)

Freek,

My point here is that G.800 is trying to come up with a generic object that describes both unidirectional TDM circuits and the packet forwarding world.  In this case G.800 uses a single concept of Link for both, perhaps this is ok, but I need to think about this some more to be confident that they can be generalized to be the same thing.

I guess the answer is that in a label switched environment they are the same thing (LSPs are static), but not in a connectionless environment because forwarding tables are dynamic?

Guy

-----Original Message-----
From: Freek Dijkstra [mailto:Freek.Dijkstra at sara.nl] 
Sent: 10 August 2009 15:22
To: Network Markup Language Working Group
Subject: Re: [Nml-wg] Use case: broadcast network (single layer)

Guy Roberts wrote:

> I propose to rename LAN_A as forwarding_rule_A and so on.

LAN_A in my example was a Link.

Are you saying that all Links are forwarding relations?

Though we don't have a concept of "forwarding relation", I'm intrigued here.

Freek
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