[cisco-voip] VoIP Deployment Questions

[Wes Sisk]

Mario,

Voice traffic is extremely sensitive to jitter and latency, just
take a look at the Cisco QOS design guides to get an idea how critical:
http://www.cisco.com/go/srnd

"Delay can cause voice quality degradation if it is above 200 ms. If the
end-to-end voice delay becomes
too long (for example, 250 ms), the conversation begins to sound like two
parties talking on over a
satellite link or even a CB radio. The ITU standard for VoIP (G.114) states
that a 150 ms one-way delay
budget is acceptable for high voice quality. The Cisco Technical Marketing
Team has shown that there
is a negligible difference in voice quality scores using networks built with
200 ms delay budgets."

The QOS design guide and IP Telephony for CallManager design guides provide
good insight on the factors leading to good voice quality.

In TAC we see many deployments over DSL and cable modem that provide
"acceptable" voice quality so long as utilization is low, but anytime
network usage surges, the lack of QOS will immediately and directly impact
voice quality.

/Wes


> -----Original Message-----
> From: cisco-voip-bounces at puck.nether.net
> [mailto:cisco-voip-bounces at puck.nether.net]On Behalf Of
> MPuras at solunet.com
> Sent: Monday, October 27, 2003 11:13 AM
> To: cisco-voip at puck.nether.net
> Subject: [cisco-voip] VoIP Deployment Questions
>
>
> Hi all.  I am in need of some guidance regarding uptime, packet loss and
> latency for national / international VoIP network.  We will be
> rolling out a
> VoIP network.  The first phase of the deployment will consist of
> getting the
> customer HQ located in Boca Raton, Fl. and one of the remote
> offices located
> in Los Angeles.  LA will have a fractional T1 to the local POP
> and Boca will
> have a full T1 at the main office to the local POP.  We will have VPNs
> between the remote offices and the HQ.  Future deployment will
> also include
> New York and London.  All packets (voice and data) will leave the
> network in
> either location as a standard IP packet.  I am in the process of
> looking at
> a few different carriers and selecting one for this national /
> International
> VoIP rollout. QoS end-to-end is a big concern for me.
>
> One of the carriers I am looking claims that it guarantees a 99.97% uptime
> and no more than .05% packet loss during any calendar month.  However they
> do not offer QoS.
>
> Is this consider acceptable for a VoIP deployment?  What sort of
> uptime and
> latency and packet loss should I be looking for?  Would you still require
> QoS if the network utilization of the carrier is half of its capacity?
>
> Any recommendations for carriers?
>
>
> Thanks.
>
>
>
>
>
> Mario Puras
> SoluNet/SoluServe TAC Lead
> Web Address:  http://www.solunet.com
> * Mailto: mpuras at solunet.com
> * Direct: (321) 309-1410
> 6 Fax: (321) 676-1287
> * Toll Free:  888.449.5766 (USA) / 888.SOLUNET (Canada)
>
>
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