[VoiceOps] VoIP on 10mb Cat 3 switched network

[Jastak, Eric]

Checking the cat3 cabling quality is good advice.  We've had a lot of experience with old cat3 cabling that did NOT play well with newer equipment.  Most of the time, we have the customer replace the old cat3 cabling if they need an analog line for paging systems, faxes, etc.,.  The older cat3 may work fine with legacy analog gear, but start running digital voice over it and you'll find all the bad runs!  :o    Packet loss will kill your voice quality.  Definitely check the quality of the cat3 runs.

-----Original Message-----
From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Mark R Lindsey
Sent: Friday, January 04, 2013 10:53 AM
To: Eric Wieling
Cc: voiceops at voiceops.org
Subject: Re: [VoiceOps] VoIP on 10mb Cat 3 switched network

In theory, 10 Mbps is certainly plenty.

But in any particular case, you've got to ask if the cabling ever used for Ethernet, or was it installed just for voice? And even if it had been used for Ethernet: it may have been dropping packets at 1% the whole time, but it was good enough for 1999 Internet, so nobody noticed.

If you have a good cable bandwidth tester, it would be smart to test. Failing that, it might work to put a phone on each port, run a 10 minute call, and look at the packet loss counts on both sides, and the error rates detected on the Ethernet switch. If they're below 0.1%, then your antique cabling might just work out.

Then your next hassle might be reconfiguring all the phones to use 10 Mbps.

On Jan 4, 2013, at 13:40 , Eric Wieling <EWieling at nyigc.com> wrote:

> IIRC a single ulaw or alaw voice call uses about 0.08 Mbps including the overhead.  I think you'll have room on your 10Mmps network
> 
> -----Original Message-----
> From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Carlos Alvarez
> Sent: Friday, January 04, 2013 1:37 PM
> To: voiceops at voiceops.org
> Subject: [VoiceOps] VoIP on 10mb Cat 3 switched network
> 
> Has anyone had experience successfully running VoIP over 10mb Cat 3 cabling?  A new customer has asked, because that's what they have in place.  I'm not interested in an unreliable solution just to save a few bucks, but in theory it should work reliably to have a dedicated 10mb to each phone and then gigabit out of the main switches.


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