A client of our uses a hosted phone solution for his 50 agent call centre. They use a hosted dialer who make the out going calls, once the connection is made the call is passed to my clients user where they pickup the connection on a 3CX phone interface.
Pretty standard stuff.
The hosting company are claiming that they are seeing 100-200ms latency for all the phones.
On testing a TCP round trip [tcping.exe] I'm getting sub 10ms times. They block ICMP. The hosting provider are saying that this isn't a valid test as the VOIP data is UDP.
I understand that UDP could be being shaped differently or routed differently but it seems pretty unlikely. The hosting IT team are very much 'we have hundreds of customers and their latency is ok, this is your problem' which I can understand but it doesn't help me much. Given that I can't control a UDP listener on their side I don't know how to demonstrate how and where the UDP lag might be coming in.
Equipment on site is a pair of Cisco 2960's connecting to a Draytek Vigor. The Draytek connects to the ISP provided/managed Cisco p887.
Bandwidth use sits at roughly 20% throughout the calling period. All the ICMP tests to external systems show good round trips, generally not beyond 5ms-30ms depending where I'm going to.
Thoughts on how to move this forward?