User Manual
U-SYS IAD108 Integrated Access Device
Chapter 5 Advanced
Configuration
5-9
Port 1 of the LAN Switch chip on the IAD108 is used as an
upstream port.
z
Accessing data subscribers.
Ports 2 and 3 of the LAN Switch chip on the IAD108 are used to
access data subscribers.
5.2.1 Configuring Precedence of Voice Packets
I.
Principle
The upstream packets of the IAD108 include data packets and
voice packets. To ensure high quality of voice and to give precedence
to voice packets, the voice packets must be separated from the data
packets. The specific way is as follows: Configure VLAN tag and rather
high precedence to voice packets on the IAD, and the packets will be
separated at the upper network equipment (for instance, the LAN
Switch).
In the example shown in Figure 5-1, the conditions are as follows.
When the voice packets are configured with VLAN tag and rather
high precedence on the IAD, the LAN Switch A will forward the voice
packets with the VLAN tag to the LAN Switch C through a special port
(“tag” in the figure) and forward the voice packets without the VLAN
tag to the LAN Switch B through another port (“distag” in the figure). In
this way, the separation of voice and data packets is realized at the
LAN Switch A.
Due to the rather high precedence configured to voice packets,
the LAN Switch A will discard some data packets and forward the
voice packets to the LAN Switch C when the network is blocked.