I have just deployed 2 new sites i Japan with IP telephony, site 1 is Yokohama and site 2 is Miyazaki.
There is a local gateway on both sites with connected ISDN BRI interfaces and the CUCM is located in Yokohama.
Furthermore Yokohama has got a new Cisco network and new cabling, they got dedicated switches for the phones.
In Miyazaki they have and old network non cisco.
Both sites complaining about bad voice quality, first i thought it was a QoS issue so i disabled all QoS in the switches, but that did not fix the problem.
Now i have found out that it is only from IP phone to gateway the problem is, the quality is perfect from IP phone to IP phone.
When considering that the 2 networks are so different and IP to IP calls sound perfect, i am starting to think that there is something with the gateway, i have checked the LAN interface on gateways and there is no drops or other errors.
When i look at the phones webpage under stream 1 that shows info about the latest stream they indicate that calls to local gateway have a MOS score about 2.0 - 2.3 using G711U so that is really bad.
There is a really high Max Jitter but the average jitter is low.
When looking at a stream from IP to IP the MOS is 4.5
It is CUCM version 9.0.1.10000 the gateways are 2901 running IOS 15.1.(4)M4 and the phones are 6941
