Re: [Diffserv-interest] Re: Diffserv-interest digest, Vol 1 #104 - 2 msgs

[Jing Shen <[e-mail]>]

IMHO, diffserv is just to define some basic rules to
be followed by ISPS who will negotiate real SLA
parameters. These parameters are to be 'implemented'
in their network and supported by routers around.
So, a coarse defination like EF, AF is enough.

Anyway, as pointed out by other people here, DiffServ
just make up logical network in physical network. This
means there will be congestion in every logical
networks.

jing shen

' spamcontrol '
 


 --- "John H. Shuler" <[e-mail]> 的正文：>
Why make a distinction between "Standard Service
> Class" and "Low Priority
> Data"?
> 
> In fact, it seems the most useful outcome of this
> paper is to help service
> providers standardize across and between their
> networks as to service class
> treatment for different service types. For this
> reason, it seems the best
> thing to do is, rather than to create these
> semi-artificial classes and
> sub-classes, to get quite specific about how to mark
> each specific service,
> e.g. IP telephony, SNA, HTTP, FTP, unidirectional
> video, interactive
> multimedia, etc. You have gone part of the way to
> this goal, but have put
> what seems to be an artificial middle step into the
> process... These service
> classes. I can see why you would do this in an
> attempt to consolidate the
> classes for ease of management, but by the time you
> are done, you have so
> many classes and variations that you have defeated
> this purpose anyway. And
> the net goal of standardizing treatment across the
> network is still not
> achieved because of the multiple options for several
> of the services.
> 
> Just some thoughts on a single, careful reading.
> 
> Also, there is some dumb editorial stuff:
> (1) Do a lookup for the word "respectfully" and make
> sure you don't really
> mean "respectively".
> (2) Look up "sufficed" and replace with
> "sufficient".
> (3) You also have a tendency to use "which" instead
> of "that"
> (4) There is an instance of using "then" instead of
> "than".
> 
> Sorry I'm too lazy to be specific about where (it's
> late).
> 
> j
> -- 
> Jay Shuler
> President
> Beyond Category Consulting
> 4020 Halkins Drive
> San Jose, CA 95124
> [phone]
> [e-mail]
> www.BeyondCategory.US
> 
> 
> > From: [e-mail]
> > Reply-To: [e-mail]
> > Date: Wed, 29 Oct 2003 12:00:04 -0500
> > To: [e-mail]
> > Subject: Diffserv-interest digest, Vol 1 #104 - 2
> msgs
> > 
> > Send Diffserv-interest mailing list submissions to
> > [e-mail]
> > 
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https://www1.ietf.org/mailman/listinfo/diffserv-interest
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> > 
> > 
> > Today's Topics:
> > 
> >  1. Re: congestion in diffserv network (John
> Schnizlein)
> >  2. Re: congestion in diffserv network (Brian E
> Carpenter)
> > 
> > --__--__--
> > 
> > Message: 1
> > Date: Tue, 28 Oct 2003 12:30:55 -0500
> > To: "Feng Y" <[e-mail]>
> > From: John Schnizlein <[e-mail]>
> > Subject: Re: [Diffserv-interest] congestion in
> diffserv network
> > Cc: [e-mail]
> > 
> > The simple reason that congestion can occur is
> that the TCA
> > need not limit incoming traffic sufficiently to
> avoid it.
> > The TCA for expedited forwarding is the only one,
> of many=20
> > traffic classes, that seeks to eliminate potential
> congestion,=20
> > in order to minimize delay and jitter.
> > 
> > The parameters of other class definitions, assured
> forwarding
> > for example, are intended to mark traffic at
> different ingress
> > rates for different treatment when congestion
> occurs. Note
> > that this anticipates that congestion will occur.
> > 
> > Please recall that the high link utilization in an
> IP network
> > is obtained in large measure because traffic loads
> are high
> > enough to produce occasional congestion.
> Cooperative management
> > of this congestion is the responsibility of
> transport-layer
> > protocols.
> > 
> > John
> > 
> > At 10:43 AM 10/28/2003, Feng Y wrote:
> >> ... I wonder why the
> >> overloading or even congestion occurs in diffserv
> network.
> >> In diffserv architecture, the =93DS ingress node
> is
> >> responsible for ensuring that the traffic
> entering the DS
> >> domain conforms to any traffic conditioning
> agreement (TCA)
> >> between it and the other domain to which the
> ingress node
> >> is connected=94 [RFC 2475]. Moreover,  
> =93Traffic conditioning
> >> performs metering, shaping, policing and/or
> re-marking to
> >> ensure that the traffic entering the DS domain
> conforms to
> >> the rules specified in the TCA, in accordance
> with the
> >> domain's service provisioning policy=94. So what
> causes the
> >> overloading or congestion in diffserv? Does
> anyone explain
> >> it for me or give me some references. Thanks in
> advance.
> > 
> > 
> > 
> > --__--__--
> > 
> > Message: 2
> > Date: Wed, 29 Oct 2003 12:07:02 +0100
> > From: Brian E Carpenter <[e-mail]>
> > Organization: IBM
> > To: John Schnizlein <[e-mail]>
> > CC: Feng Y <[e-mail]>,
> [e-mail]
> > Subject: Re: [Diffserv-interest] congestion in
> diffserv network
> > 
> > Another way to look at it is that what diffserv
> does is split the network=
> > 
> > into several separate networks, but each of them
> retains the statistical
> > properties of a single Internet.
> > 
> >  Brian
> > 
> > John Schnizlein wrote:
> >> =
> > 
> >> The simple reason that congestion can occur is
> that the TCA
> >> need not limit incoming traffic sufficiently to
> avoid it.
> >> The TCA for expedited forwarding is the only one,
> of many
> >> traffic classes, that seeks to eliminate
> potential congestion,
> >> in order to minimize delay and jitter.
> >> =
> > 
> >> The parameters of other class definitions,
> assured forwarding
> >> for example, are intended to mark traffic at
> different ingress
> >> rates for different treatment when congestion
> occurs. 
=== message truncated === 

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