how is dot1q tagging used in QoS for voip

thomas130

I was wondering if someone could explain how this works or point me to a website that would show me how this works

Thanks

pitviper

It isn’t really a QoS function – Rather an encapsulation protocol used when sending multiple VLAN tags on trunk links. You’ll see it used in voice to keep the voip traffic separate from the data traffic (more so for security).

More here:
IEEE 802.1Q - Wikipedia, the free encyclopedia

kalebksp

You can mark the dot1Q tag with a CoS (Class of Service). This is useful when you want to mark traffic on layer 2 switches which cannot mark the DSCP bits in the IP header, such as you might have in the access layer of a network.

Additional information: Class of service - Wikipedia, the free encyclopedia

pitviper

Ah yes, forgot about Layer-2 fields hiding in there. I automatically think DSCP because that’s all that I use!