So here is an interesting one, and our tech is still looking into it, no one seems to know the answer so I thought I would ask here...
We have new Mitel enterprise system, hosted by Mitel in their datacenter. We have an MPLS network linking 13 sites, including a direct connection from our MPLS network into the Mitel datacenter right to our phone system.
We use mostly 5360 model phones and connect them to the phone system via the MPLS private ip 172.16.x.x direct to our ICP - they show in the system as an IP Direct connection, and most work fine this way.
We have a few sites where, when answering a call there is a 2 - 3 second audio delay - where it is one way audio - the inbound caller can hear us but we can not hear them for the 2 - 3 seconds. Now if I re-configure the phones that randomly have the audio delay to connect to the public IP address of the phone system so it goes through the MBG - they have zero audio delay issues - no problems at all. If I switch them back, the start having the issue randomly.
We have checked our QOS settings on all the routers (Adtran). All traffic at these sites go out through the same Adtran MPLS router (voice is on a separate vlan). If it goes to the private phone system link it goes straight to the Mitel datacenter. If it goes to the public Mitel IP the traffic has a much longer route with many more hops - as it goes to one of our internet access sites then out over the public internet then back into the MBG. The issue will randomly happen, doesn't matter if the circuit is mostly idle or under heavy use.
I would think it would have more problems going public to MBG vs the direct MPLS route...
Has anyone experienced this before? Is there a different protocol setting or something for the phones? Do they negotiate differently when direct to the ICP (IP Direct) vs MBG?
