Call Transfer Delay

mcs3ss2

Active Member
Sep 8, 2020
297
37
28
AU
Hi Team,

I am having a weird issue. Here is the scenario.
tenant1.domain.com with 7 extentions
Incoming working normal
Outgoing working normal
Ext to Ext calls working normal
Hardware Phone Yealink T54W

Issue:
When tranferring calls between Ext 1 to Ext 2 (Example) there is transfer delay of about 20 seconds. Ext 1 says instantly transfer complete but Ext2 does not start ringing untill after about 20ish seconds.

What I have tested:
Configured both extentions in my office and transfer is working as it should i,e instant transfer. but on client site issue remains.
I have created new 2 Ext and tested with same results.
I have used (Telstra NBN Australia) but issue remains
I have used starlink internet but issue remains
I have bypassed all the network devices and connected phones to internet directly No switch or firewall in between just the phones and the internet, just the ISP modem. Same issue with Telstra NBN and Starlink.
Client site Interspeed is consistant 50 Mbps down and 20 Mbps Up with Latency/Ping between 10-20ms on PCs. In PBX portal registration page shows ping between 50-90ms. I know slightly higher than I like but this has always been the case. I have other clients in the region with same average ping and no complaints.

Question:
What am I missing? Only i can think of is to delete the domain or create a new domain and test with new domain tenant. Other than that nothing I can think of.

Thank you for your input gents.
 
Try switching from UDP to TLS and disabling SIP ALG. Best if you go to TLS. When it's one site only, the issue is always with the client's network.