If we are talking about a 1335, there are two areas you can use to improve and prioritize the voice.
1. CoS (Class of Service). Make sure that the class of service queuing is enabled on the device, and set it to strict-priority if your device supports it. Then make sure that your Voice/SIP server is configure with a CoS value of 5 or higher. If that is not possible, you can set the default class of service on the switchport to 5 or higher. This would be the port the Voice/SIP server is using.
2. QoS (Quality of Service). Configure traffic shaping on the outbound circuit and configure a QoS policy that matches the RTP traffic or IP address of the SIP server. In my installations, I configure the SIP server to tag packets with DSCP values, but you can match access-list or RTP.
qos map RTP 10
match RTP range 10000 10500 all (whatever the range of RTP ports is for your configuration). "all" means even and odd port numbers.
set precedence 5
interface vlan 100 (whatever your outbound IP interface is )
ip address x.x.x.x y.y.y.y
traffic-shape rate 4M
qos-policy out RTP
This should match all RTP packets and give them priority over normal data packets. NetVanta routers can only control outbound traffic, If this is an internet connection, then it's best effort anyway.
I hope this helps.
That I understand if the traffic goes threw the adtran firewall and the source is the vlan address, but does this apply to the connection to the other router the customer has plugged into port 2 using a different WAN address so that traffic does not go threw the vlan 10 interface? Basically I need the traffic from the vlan 10 address to take priority over the traffic on port 2, or in other words the customers existing router on the same subnet on the WAN interface? Thanks!