Re: Reg: Quality of Service routing

Richard Carlson <> Tue, 22 December 1998 01:10 UTC

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Date: Mon, 21 Dec 1998 13:10:04 -0600
To: "Raghu V.V.J Vadapalli" <>
From: Richard Carlson <>
Subject: Re: Reg: Quality of Service routing
Cc: routing quality <>, Internet Protocol <>, MultiProtocol Label Switching <>
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This is a very interesting and important question that I don't think gets
the attention it deserves.  As has been pointed out in other replies to
your question, the cost of providing 'enough' forwarding capabilities
(switch/routers, link BW, etc) to prevent packet queuing will be high.  The
unstated (and I believe suspect) assumption is that the cost of providing
QoS mechanisms will be lower.  I don't think enough research has been done
to identify and classify the real costs of deploying a QoS based Internet.

By real costs I mean those charges that are required to build a workable
global system.  Some simple examples are:

* authentication, can I prove who I am and that I have the authority to
request this service?

* non-repudiation, can you prove it was really me so you can counter my
claim that I never used this service?

* charging, who pays for traffic in the non-symmetric data world where the
web server is the 'source' and the client is the 'sink' for data streams.

* cross domain charging, how do service providers pass charges to each
other and finally back to the customer.

* equipment requirements, how much will equipment (switches/routers,
computers) cost when they need to keep track of all the accounting

I am not trying to say that any one of these issues is expensive by itself,
but that the combination of all the components needed to build a workable
global QoS Internet must be addressed.  Only then can a fair comparison be
made to determine what the best answer is.

Looking at the total picture, I begin to view the technical solution of
just throwing more packet forwarding capability (faster switches/router,
links, DWDM muxes, etc.) as very attractive.  The costs for the technology
will only come down.  Indead, look at the new terabit routers now being
worked on, wire speed forwarding engines at gigabit speeds in campus
switch/routers, and optical networks using NxOC-192 DWDMs.  All of these
technologies tend to decrease in price as time increases.  In contrast, who
knows what the administrative costs will be and how they will change over

Building a high quality Internet will not be an easy task.  Right now I
think it is to early to tell if technological growth or administrative
constraint is the solution to this interesting problem.


Raghu V.V.J Vadapalli wrote:
> Dear All,
> I have one basic question regarding QoS routing.
> Do we need QoS routing if we have enough infinite (I mean
> large ) bandwidth.
> From my poor knowledge:
> We need QoS routing b'cos we have limited BW and we want
> to give priority to QoS flows. If some one comes with
> a Tx system which supports 100s Gb/s,(say 128 channel WDM system)
> Do we need to support the "special"  status for the QoS flows.
> May in that case the memory at the routers will be
> bottleneck.
> Am I missing something.
> With Regards
> -Raghu.

Richard A. Carlson			email:
US Dept of Energy ER-31      		Phone: (301) 903-0073
19901 Germantown Rd			Fax:   (301) 903-7774
Germantown, MD 20874