Subject: RE: [Ieprep] Measurement of Internet Congestion

From: "Nguyen, An" <[email-masked]>
Date: Tue, 12 Nov 2002 12:49:32 -0500

Bill,

I went through your presentation slides in one of those you said "Sound
quality far exceeds
that of PSTN". I don't technically agree with it. The reasons are as
follows:

1. If your network does support G.711 voice codec at all, then QoS in your
network might be as good as G.711 in the PSTN given that there are no
hick-ups or congestions in your networks. If your network only supports much
narrower voice band such as G.729, G.723.1 or GSM, the QoS is obviously
noticeable as we all experience with low bit rate codecs in the cellular
wireless networks. According to the ITU Means of Score (MoS) , G.711 is
about 4.3 and other low bit rate codecs are in the 3.0 ~3.5 range.  In
short, G.711 is G.711 regardless of the transport layer. If your network
supports wide-band audio codecs for telephony ( which I doubt) , then I
would sincerely like to withdraw this comment.

2. Let me tell the experience with the VoiceIP deployment I have been
involved with. NCS had a project to build a private packet-based network
supporting VoiceIP and videoconferencing traffic for closed groups of users
that are geographically dispersed. Basically, this private network was built
based on Frame Relay for access and ATM for transport. After the request for
information on the project was put out on the web, we got five or six
LARGEST vendors' responses. None of them wanted to guarantee end-to-end High
Availability of 99.999 ( as currently provided in PSTN) for this service.
They said the max they could provide was 99.9 because they can't control the
access points which generally are owned by different service providers.  

Let's say your network has no problem whatsoever because of its unique
architecture. But the rest of the ISPs, I can imagine,  would have this kind
of problem: access. And NCS has to deal with many ISPs to address this issue
in order to get ubiquitous.

Regards,

An 

From: Bill Woodcock [mailto:[email-masked]]
Sent: Saturday, November 09, 2002 2:23 PM
To: RJ Atkinson
Cc: [email-masked]
Subject: Re: [Ieprep] Measurement of Internet Congestion

      On Sat, 9 Nov 2002, RJ Atkinson wrote:
    > 	You at least owe us a URL or bibliographic citation to your own work
    > if you are using it as your justification.  Henning was good enough to
    > provide a specific URL and bibliographic citation, which helped focus
    > things a great deal.
    > 	Maybe you could find some presentations from NANOG, RIPE, or APRICOT
    > that are online and relevant to the discussion ?

The slide-set from NANOG is at:

http://www.pch.net/inoc-dba/INOC-DBA-announcement.htm

Slide 9 has a chart with calls-per-day in yellow and number of phones in
use in red.  Of course, they're out-of-date now, since we're into
November.

Slide 8 is PAF's nephew, setting up his phone.  Which worked fine, by the
way.  :-)

                                -Bill

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---

From: Bill Woodcock <[email-masked]>
Date: Tue, 12 Nov 2002 09:56:59 -0800 (PST)

On Tue, 12 Nov 2002, Nguyen, An wrote:
    > In short, G.711 is G.711 regardless of the transport layer.

Yes, of course.  However, on the PSTN, that's switch-to-switch.  Several
miles of bridge-tapped 28-gauge junk away from each user, in nearly the
best case.  In an ideal world, you'd have ISDN desk-sets in front of every
POTS user, but I don't hear anyone suggesting that.

    > Let me tell the experience with the VoiceIP deployment...
    > None of [the RFP-respondents] wanted to guarantee end-to-end High
    > Availability of 99.999

That's not deployment experience, that's you talking to a salesperson.
Which has exactly nothing to do with networks or operational reality, or
voice quality.

    > They said the max they could provide was 99.9

Okay, hypothetically, let's say they really are as bad as the worst that
they were actually willing to guarantee in writing.  If they lose one
packet in a thousand, do you really think that VoIP will fall apart at the
seams?  Do you think that'll even have an effect which could be measured
in the lab?  Much less noticed by happy users?  VoIP seems to me to work
pretty darned well at 96%-97%.

    > ATM for transport

Ouch.  Yeah, well, if you actually did build the network and had problems,
there's your source.  Fortunately the Internet hasn't used any significant
quantity of ATM since it was deprecated a few years ago.

    > NCS has to deal with many ISPs to address this issue

Yes, tens of thousands.  I'm still having a bit of a hard time with the
notion that NCS really wants to enter into and manage SLA contracts with
tens of thousands of ISPs.

                                -Bill

---

From: RJ Atkinson <[email-masked]>
Date: Tue, 12 Nov 2002 19:36:03 -0500

On Tuesday, Nov 12, 2002, at 12:56 America/Montreal, Bill Woodcock 
> quantity of ATM since it was deprecated a few years ago.

Bill forgets that a large UK-owned ISP is still built out primarily
upon wide-area ATM infrastructure.  ATM is not particularly growing
among the IP oriented community and Ethernet is killing off ATM in
the LAN/MAN, but there is still a fair bit of ATM around in the world.

Ran