RE: [Diffserv-interest] Re: draft-baker-diffserv-basic-classes-01 .txt

"Jozef Babiarz" <> Sun, 02 November 2003 21:54 UTC

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Message-ID: <>
From: "Jozef Babiarz" <>
To: Brian E Carpenter <>, "John H. Shuler" <>
Subject: RE: [Diffserv-interest] Re: draft-baker-diffserv-basic-classes-01 .txt
Date: Sun, 2 Nov 2003 16:52:18 -0500
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Brian E Carpenter wrote:
John, I guess your comment refers to the draft so I changed the subject.

If you want to be sure the authors see your comments, you might want to
write to them directly. My reactions inserted below.


"John H. Shuler" wrote:
> Why make a distinction between "Standard Service Class" and "Low Priority
> Data"?

There is a kitchen sink aspect to this draft that worries me. Rather than
starting simple, with three or four generic service classes, the authors
have chosen to present the union of a number of diffserv deployment models.
I think that risks confusing operators by giving them too much complexity
to choose from.

[[Joe] The draft tries to address the service differentiation that is needed
in carriers and enterprise networks including access networks. I agree that
network administrators both in carrier and enterprise should start off with
only the service differentiation level (service classes) that are required
for their business. Let me provide some examples that I worked on so that
you can understand why we have defined the number of service classes.

Carriers wanted to use IP technology for provide telephony service, plus
provide IP VPN service with CIR as well basic Internet connectivity service.
This scenario can be address by configuring the network using the following
service classes define in the draft.
- Standard service class for Internet connectivity
- High Throughput Data service class of IP VPN and collection of network
data for billing
- Telephony service class for VoIP and signaling between voice gateways
- Network Control service classes for routing, etc.

This simple example used four of the defined service classes.

A different operator is deploying the services listed above plus new
multimedia IP services like desktop video conferencing to go along with
telephony, instant massaging plus other "workflow" applications.
This operator needs: 
- Standard 
- High Throughput Data 
- Low Latency Data 
- Multimedia Conferencing 
- Telephony 
- Network Control

Another operator has plans to offer broadcast TV service, pay-per-view,
telephony, two different SLAs for IP VPN services and basic Internet
connectivity. They will need:
- Standard 
- High Throughput Data 
- Low Latency Data 
- Multimedia Streaming 
- Telephony 
- Network Control

A large enterprise is currently configuring their network to support the
flowing service classes (using the drafts terminology). Most location will
have a subset of services available with migration to network wide service
transparency in the future. 
- Standard 
- High Throughput Data 
- Low Latency Data 
- Multimedia Streaming 
- Multimedia Conferencing
- Telephony 
- Network Control
- Administration

I can go through more scenarios that I have come across over the years. 
I agree that two or three user service classes is what many operators start
off with, however they are not always the same three and they always like to
know how they can evolve in the future.]

Regards, Joe.
Jozef Babiarz
QoS and Network Architecture
Nortel Networks
Tel: (613) 763-6098 ESN:393-6098