I have a pair of Cisco 3725 routers that I'm talking through using VOIP. I measured a mouth to ear delay of 70ms with a standard config. Is this what I should be getting? Is there a way to make the delay 0?
- posted
17 years ago
delay of 70ms
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- posted
17 years ago
Are they connected by LAN or WAN? What codec and packetization period are you using? What type of voice terminal are you using?
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17 years ago
LAN,
G.711 ulaw 20ms,
standard POTS phone
R-Guy wrote:
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- posted
17 years ago
With 20ms packetization, it will be impossible to get less than 20ms delay, because that's how much data the gateway has to collect before sending a packet. There's also typically 10-20ms burned in the codec/DSP's pipeline. On top of that, the receiver's jitter buffer will add a few tens of ms; most jitter buffers, even adaptive ones, are tuned with a minimum of a few tens of ms because it doesn't hurt, and 40ms or so of buffering will hide all but the worst unless you have no QoS at all over a skinny WAN pipe.
70ms isn't bad, and no human should ever notice it. Don't worry about latency until it hits 150ms. S