Strange issue with the 3300

[m600ant]

Hi, we have an issue with our 3300 and wonder if anyone has any pointers for me..  Our phone system runs over 2 buildings connected with fibre, it has been working perfectly over a single vlan spanning the network but I need to seperate the buildings for DR purposes so have created vlans with gateways in the remote building.  When I do this the phones function fine but i get reports of bad call quality and dropped calls so have to revert back.  I also see entries like this in the logs:

Maintenance      312      Info      2017/Oct/09      09:22:57      E2tSp      IP Network Dropped 5.08 percent of Packets from phone 10.150.6.43 Total Rx: 6397 Lost=197 maxLossBurst=10 1 in a row: 8 2 in a row: 5 3-5 in a row: 33 6-10 in a row: 8 11 or more: 0      E2T      Maintenance;0   
   
I have monitored the connection between the buildings and it is not being saturated,  I have tried configuring QOS on all switches and routers inbetween, keeping the same vlan tag and disabling spanning tree broadcasts over the link but nothing works.  As soon as i revert back so it is not routed there are absolutely no complaints..  Any ideas ?

[acejavelin]

This is not an issue with the 3300, it is with your network... router queuing if I had to guess... somewhere a device doesn't have a enough horsepower to handle the routing you are doing (again, just a guess based on the limited information you have provided).