Working Principles
By transmitting data streams and voice streams in the data VLAN and the voice
VLAN respectively, the voice VLAN-supported equipment avoids mutual
influence between them. Meanwhile, the equipment issues priority policy to
improve the priority of voice streams and guarantee session quality. The basic
working principle is described as below:
Step 1: The user creates on the equipment one VLAN dedicated to transmitting
voice packets, i.e., Voice VLAN, and enables Voice VLAN function on the port
that connects with IP phone.
Step 2: As a key step, the port that connects with IP phone joins Voice VLAN in
different ways by the working mode of Voice VLAN:
Under auto mode, after receiving untagged message from the port, the
equipment will match its source MAC address with legal OUI address. If the
source MAC is OUI address, the message will be considered to be voice
message. And the equipment will automatically join the port in Voice VLAN, and
learn this MAC address on the port at the same time.
Under manual mode, subscribers should manually configure the port which
connects with IP phones to join Voice VLAN.
Step 3: Whether under auto mode or manual mode, the equipment will issue a
policy and improve the priority of packets whose source MAC address matching
the OUI address of voice VLAN. The CoS is set to 6 and DSCP is set to 46 for
matched voice packets.
Following these steps, the port that connects with IP phone joins Voice VLAN,
and voice packets will be centrally transmitted in Voice VLAN and forwarded out
with high priority.
To Next Page
Loading...
