> Your instructor is one of the all-too-large group of people who try
> to coerce things into a simplistic OSI model. Priscilla calls this
> coercing protocols into OSI layers. It's really not the fault of OSI,
> because there are documents that supplement the original model, such
> as the Rout(e)ing Framework, Internal Organization of the Network
> Layer, Management Annex, etc.
>
> The OSI stack principally was drawn to show how standard
> communications service user applications, which run on top of the
> service interface to the application layer. Management was something
> of an afterthought, and what is called system management -- think
> SNMP, or the OSI rough equivalent, CMIP -- does indeed involve an
> application layer protocol and a management application above it.
>
> Routing, error notification, etc., are considered layer management.
> There is nothing "above" them; they are part of the infrastructure
> for a given layer. So,all of them are logically layer 3.
To further cloud the discussion, I've heard folks argue that MPLS is a layer
2 1/2 protocol, and I've also heard folks argue that MPLS is a layer 3 1/2
protocol since it rides on top of IP (though how something could ride "on
top" of IP yet control the data link layer baffles me).
Would it be fair to say that MPLS is therefore a Layer 2/3 control protocol,
and is therefore outside the typical OSI layers? Or, is it a Layer 3
protocol?
_________________________________
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
