Subject: [Diffserv-interest] Re: Diffserv-interest digest, Vol 1 #129 - 1 msg

From: "John H. Shuler" <[email-masked]>
Date: Thu, 13 May 2004 09:52:50 -0700

This is true. However, one must assume that the core has been properly
engineered to provide appropriate delay and jitter characteristics for the
appropriate level of total class bandwidth, or else nothing will work no
matter what you do at the edge. Therefore, the work done at the edge is
extremely relevant to the overall performance of the different traffic
classes.

And yes, MPLS can make a huge difference in terms of making behavior more
deterministic. However, it also suffers from different implementations
across carriers, so peering agreements must be in place to ensure end-end
QoS even with MPLS.

Comments?

j

> From: [email-masked]
> Reply-To: [email-masked]
> Date: Thu, 13 May 2004 12:00:06 -0400
> To: [email-masked]
> Subject: Diffserv-interest digest, Vol 1 #129 - 1 msg
> 
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> Today's Topics:
> 
>  1. Re: CIR in AF class (Brian E Carpenter)
> 
> --__--__--
> 
> Message: 1
> Date: Wed, 12 May 2004 18:27:01 +0200
> From: Brian E Carpenter <[email-masked]>
> Organization: IBM
> To: [email-masked]
> Subject: Re: [Diffserv-interest] CIR in AF class
> 
> Yang,
> 
> If different entry points to a diffserv domain apply different
> admission control rules then traffic entering at those points will
> get different shares of the bandwidth at the entry point, but once the
> traffic gets mixed up in the core of the domain, all traffic sources
> will be getting the same treatment. In other words any CIR differentiation
> at the entry points will vanish in the core.
> 
> (That's assuming an IP network of course... MPLS is a different story).
> 
>    Brian
> 
> Feng Y wrote:
>>>> Also, CIR treatment at the edge can be very
>>>> different.
>>> 
>>> What do you means by "different"? implementation
>>> details or the traffic shaping/policing policy?
>>> 
>>> To my understanding the same PHB reflects the same
>>> view of traffic across a policing point although there
>>> may exist great differnce in implementation methods.
>>> 
>> 
>> 
>> Do you mean that although the implementations are
>> different, the results are the same - defferent flows have
>> same CIR? Or, the flows which have the same CIR maybe
>> assigned different bandwidth according to the current
>> network state?
>> 
>> Thanks.
>> 
>> Yang
>> 
> 
> 
> 
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> End of Diffserv-interest Digest

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