[asterisk-users] audio session start delay

[Luca Corti]

Hello everyone,

I've set up an asterisk box with basic PBX features (DiD, MoH, MoT,
Blind and Attended Call Transfer, PickUp, ecc.) for 10 Cisco 79xx (7912
and 7960) with SIP image (8.0). PSTN gateway is done using a Cisco
AS5350 with two ISDN PRIs connected to Asterisk via SIP. Between the
phones and the PBX I have a router doing NAT and a 4mbit synchronous
line.

Sometimes when calling between extensions, after successful signaling,
there is a delay of 10 seconds before any audio is heard by both
parties.

Do you know what can cause this behaviour? Is this more likely to be a
phone or an Asterisk issue?

thanks