[VOIPSEC] QoS vs VoIP security

Panos Koutsougeras pkoutsougeras at gmail.com
Sun Apr 23 09:06:52 PDT 2006

The voipsa threat document (
http://www.voipsa.org/Activities/VOIPSA_Threat_Taxonomy_0.1.pdf) on page 33
says this:

"Performance Metrics
To be considered as providing same or better than toll quality telephony
provided by the PSTN, the following media performance metrics are defined in
ITU-T-G113 and ITU-T-G114:

· Latency < 150 ms
A latency of 150ms – 200ms, though usable, results in 'choppy' media
Latency greater than 200ms, is typically considered unusable as delays
normal 'conversation'.

· Jitter < 25ms
Buffering at the receiver can reduce the effect of jitter.
Excessive jitter introduces delays and affects media exchange in similar
ways as

· BER < 0.25%, Packet Loss < 0.5%
As media typically uses UDP, an unreliable IP transport protocol, there is
limited recovery from packet errors and loss. Packet loss below the
threshold is usually imperceptible. Excessive packet loss introduces delays
affects media exchange in similar ways as latency."

Does everyone agree with these ITU guidelines in their own practice?  Or
does it vary wildly based upon the particular application, device, codec,


On 4/19/06, Sergey Vointsev <vointsev at gmail.com> wrote:
> > In this moment i'm working in my PhD Thesis "QoS vs VoIP security"
> > Any person have any type of information in relation to the afectations
> > the Security (VPN, IPSec, IDS, Firewalls, SRTP, IPv6) in the diferents
> > parameter of the QoS (jitter, delay, MOS, etc)
> Have a look to Ethereal - open source traffic analysis tool.It can
> capture all traffic and give a lot of different information about each
> packet. The most interesting for you - it can analyse
> not only packets, but also entire RTP streams and give interesting
> statistics about packet loss, jitter, delay etc. All this data can be
> displayed as detailed graphical charts.
> --
> Also available for instant messaging via Google Talk.
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