RE: [Dcpel] Purpose of a diffserv control plane

"Roy, Radhika \(AEAD\)" <> Mon, 14 November 2005 19:58 UTC

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Subject: RE: [Dcpel] Purpose of a diffserv control plane
Date: Tue, 8 Nov 2005 14:15:14 -0500
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From: "Roy, Radhika \(AEAD\)" <>
To: "Hancock, Robert" <>, "Pulliam, Jeffrey S" <>, "Kathleen Nichols" <>, <>
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Hi, all:


It seems to be that 5 points articulated by Robert may describe the
overall DCPEL schemes. The only other point that may need to be added:
"Specific to DiffServ services."






From: [] On Behalf
Of Hancock, Robert
Sent: Tuesday, November 08, 2005 1:28 PM
To: Pulliam, Jeffrey S; Kathleen Nichols;
Subject: RE: [Dcpel] Purpose of a diffserv control plane


Hi Jeff, Kathie, 

I think the problem that I am having (and maybe some others) in 
following this discussion is that the problem scope is potentially 
so enormous that it is difficult to work out how to start 
discussing it, and commonplace for discussions to proceed at cross 
purposes because people are talking about different bits of it. 

Kathie's prior mail described this activity as the diffserv analogy 
of moving from static routes to RIP. However, if the model is of 
network-level controller nodes which manage groups of routers, a 
closer analogy (to my mind) would be moving from static routes to 
inter-domain MPLS. (I'm not saying this approach is wrong, just 
trying to stress that it is quite a leap.) There is also a
problem, that words like 'signaling' or 'control function' mean 
very specific things to some people, but to others are extremely 

My very crude take on what Jeff describes below is that one can 
imagine 5 different components to the problem, i.e. 
1) a language for describing the services that are requested 
2) logic for deciding whether and how to implement the requests 
3) a protocol mechanism for initiating requests with domains 
and carrying requests between them 
4) interaction with AAA (especially authorisation/accounting) 
functions to support the decision process 
5) protocol mechanisms to implement the decision in the forwarding 

Now my question is whether the purpose of DCPEL is to work specifically 
on some or all of these, or whether initially it is to work on 
understanding how they fit together (or on some similar decomposition). 
Note that at least (3), (4) and (5) could all be described as 
'signalling', and (2)-(4) as 'control functions'; OTOH I got the 
impression last night (maybe incorrectly) that Scott at least was 
mainly interested in (1). 

Or have I missed the point entirely? 

Robert H. 

ps. see you at lunch :-) 

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