Is LAN QoS required for VoIP applications? We have basic network infrastructure:
PC (Softphone) -GigEth-> [Switch] -GigEth-> [Router/Firewall] -> Internet (100 Mbps) -> [ITSP]
Voice traffic flows via switch and firewall towards my IP Telephony Service Provider. We have around 50 users which may place simultaneous calls. (Bandwidth per call is around 80 Kbps - Kilobits per second) and Softphone doesn't mark traffic with DSCP, use BE (0). We have received some complaints about voice quality. I believe 1 GB ethernet is more than enough per PC.