Robert E. Seastrom rs at
Sun Aug 20 07:46:18 CDT 2006

Will Russell <will7777r at> writes:

> Andre,
> Could you share with us which type of internet service your son was
> using, and it's rated bandwidth?  With FIOS 5 meg download bandwidth,
> it's hard for me to imagine downloading such a large file that it
> would impact on a digitized audio signal (~64K/sec).  Also, the
> reviews suggest that there are significant differences between the
> various VOIP offerings.

Well, it matters not how big the file is, but how many simultaneous
TCP sessions are running absolutely makes a difference.

Under normal conditions a TCP stream will "get out of the way" of a
non-ack-constrained stream such as a VOIP phone call.  Bandwidth
utilization on a VOIP call varies with the codec used, but the
best-sounding (and noncompressed) mu-law or a-law G.711 will have
64kbit/sec of payload, which translates to about 80 kbit/sec on the
wire when UDP, IP, and ethernet headers on each packet are taken into

Vonage is immensely popular, and has suffered some pretty serious
growing pains.  While possibly a component of his dissatisfaction, I
don't think this was the main thrust of what Andre's son was seeing.

You may be familiar with a protocol (and set of clients that speak it)
known as Bittorrent.  Unlike other peer to peer technologies,
Bittorrent seems to culturally attract for the most part legitimate
traffic such as Linux distributions and other files that are large
enough that distributing them from a single central site would result
in a high bandwidth bill.

Unfortunately, Bittorrent opens up a lot of simultaneous TCP sessions
and can have as many as 20 to 40 going simultaneously to various peers
with which it's exchanging tiny chunks of file.  20 or more TCP
sessions "get out of the way" of the UDP session of the phone call a
lot less efficiently than a single TCP session.  Annoyingly, a lot of
the Bittorrent clients kind of suck when it comes to throttling total
outbound (and inbound) bandwidth and will tend to eat everything
available even if you set the dial lower.

There are tricks you can use to handle this a little better with a
home router that always sends the VOIP packets first, but that doesn't
help you in the other (download) direction.

> Regarding fax, I've been tempted to use one of the internet fax services.

Two ways to do this.  One is a fax service that sends you email
attachments with your faxes in them or email notifications that you've
got a fax waiting.  The other is a VOIP provider that provides T38 fax
relay service, which essentially means that there is the DSP
equivalent of a fax modem built into your TA, which turns the fax data
from a fax machine you've plugged into it into a bit stream, which
then goes to another fax modem where the data re-enters the PSTN.
That means you keep your normal fax machine.  Your choice as to what
you're trying to accomplish.


> Will
> Andre Kesteloot wrote:
>> Will Russell wrote:
>>> Andre,
>>> Just in case, I retained a fax line on copper. Actually, I only
>>> signed up
>>> for the FIOS internet service, but the TV is sitting there in the box
>>> outside my back door.  No problems with the FIOS phone (don't know about
>>> alarms).  It does lead me to think about going to Voice Over IP at a
>>> significant savings over retaining the telephone features from the old
>>> copper line. (It seems like that's what Verizon is really doing with the
>>> voice FIOS.)
>> about VoIP, my son Lawrence wrote to me today:
>> "I wanted VoIP to replace my landline, I didn't want to pay for both.
>> But VoIP couldn't send faxes reliably.  So I had to keep my landline
>> anyway for faxing and therefore got rid of VoIP.  It had some nice
>> advantages, like free voicemail, call waiting, etc., infinite free
>> calls in the US and Canada.
>> There were some other disadvantages.  If you were uploading or
>> downloading a lot of data, the sound quality deteriorated very
>> quickly.  It didn't work when your Internet connection went down or
>> your power went out.  There was uncertainty about whether 911 would
>> know where you are.  We were with Vonage, and they've been losing
>> money since they started and are losing customers. "
>>> Another potential reason to keep copper is that the FIOS box works on a
>>> battery, which will eventually discharge if there is a major power
>>> failure.
>>> Albeit, one may have other sources, such as back up generators.  Believe
>>> this is a similar situation should one choose Cox phone service,
>>> but have no
>>> personal experience.
>>> Will, KM4VJ
>> thanks, Will for the detailed response. Do you know anyone who has
>> signed up for the TV deal ?
>> best regards
>> André  N4ICK
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