Alcatel Unleashed

Hi~
The attachment is the system architecture diagram
When SIP phone 6802 calls TDM phone 5300, 5300 can hear the sound from 6802, but 6802 cannot hear the sound from 5300 .
However, after about 30 to 40 seconds, SIP phone 6802 can hear the sound from TDM phone 5300

Additionally, when I dial the main site PSTN number (E1 ISDN), I can immediately hear the company greeting
It seems there is an issue with RTP transmission, but why is there a delay of 30 to 40 seconds?
(Based on the Wireshark analysis, it is indeed observed that there is a delay of 30 to 40 seconds before the sender receives packets from the receiver)

looks like network issue , qos is managed ?

The branch office only has two people, so I think the company probably wouldn't have managed QoS
I will check it , thanks

Hi~
Just yesterday, when I was trying to capture packets between the WAN and the firewall, it suddenly started working... I don't know why
Before that, I tried testing with an Alcatel SIP phone H3G, and the problem still existed. But right after, when I attempted to capture packet
using SIP 8001 for testing, the issue disappeared.