[rescue] 802.11 + VoIP

vance at neurotica.com vance at neurotica.com
Sat Oct 18 23:59:46 CDT 2003

On Thu, 16 Oct 2003, Joshua Snyder wrote:

> > Performance is not an issue with VoIP, latency is. To get a decent
> > VoIP connection you need to sustain 64k BITS per second of DATA, which
> > means about 96k-128k of IP throughput. Just about any WiFi network can
> > do that, but if the delay is too long in getting a packet out there,
> > then there will be echo and other problems.
> The other thing to remember is that wireless will have variable levels
> of quality.  From my experience latency can be a problem when doing VoIP
> over wireless but packet loss will kill you.  VoIP almost always uses
> UDP packets and UDP packets do not have guaranteed delivery.  So if you
> have a bad WiFi signal and you have a large amount of packet loss the
> phone will just cut-out on you... Just ask Dan Sikorski, just two nights
> ago I called him via a VoIP phone.  In this case the last hop before the
> phone switch was over a woreless connection at the time the signal was
> very bad and even though the latency was only about 150ms the packet
> loss was around 12%... it didn't take long for us to switch back to
> using Icq.  Other times I have use the exact same setup and have had no
> problems... your mileage may vary.

Get a better antenna.  Or an amp+antenna.  I'm running a network at almost
a half mile with no dropped packets and decent bitrate.

Peace...  Sridhar

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