[oclug] POTS -> SIP providers in Canada?

[Adrian Irving-Beer]

On Mon, Apr 25, 2005 at 07:46:09PM -0400, Brad Barnett wrote:

> Unless you are dropping upstream bandwidth to about 65% or 70% of
> full speed, you aren't assured that the modem won't queue the
> traffic itself.. and cause delays in traffic you don't want delayed.
>
> If he's had no complaints, it has been luck... or people not
> commenting on the quality.

The link in question was calibrated in particular to prevent any
severe SSH delays during major downloads or even major uploads.  We do
a lot of those, and it frustrated me to no end -- until I set up
proper rules. Now VoIP benefits from those.

I also used TCP MSS tricks to lower the TCP packet size of our more
common major data transfers, ensuring that the queuing disciplines
could more effectively perform their job.

It does involve some limiting, yes.  But with the steps above, the
limiting doesn't need to be particularly low.  I found it was less
about percentage and more about a fixed margin; hence, the percentage
loss decreases with higher speeds.

Sorry I don't have exact numbers -- I did this all ages ago.  I know
what it's set to, but I just don't know what percentage of the
effective max that is.

> If he's had no complaints, it has been luck... or people not
> commenting on the quality.

Believe me -- if he had a network issue, I'd hear about it. ;)

And as for luck, he uses it most of the day, talking to clients.  Bad
luck has had many chances to manifest.

> > Also, according to one report I heard, a Linksys VoIP box reduced
> > someone's bandwidth from 400 kb/s to 200 kb/s *all* the time, even
> > with no call in progress.
>
> Perhaps a VOIP QOS router, and not a router with SIP built in.

I'm not familiar with what you're referring to here -- I know what
each acronym means, just not how they all fit together. ;)

In any case, if it clarifies things:  This was one of the Linksys
boxes I mentioned.  They have a WAN port (like a normal router),
some LAN ports (ditto), but a phone port that hooks up to a normal
land phone.

They're meant to simultaneously be your VoIP and your home router, but
apparently (according to the forums) some people put them behind a
different router due to the bandwidth limiting issue.
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