LIP-8002/8002A
iPECS
Installer
Guide
70
priority, handling higher priority packets first. However, at congested routers, higher priority
packets are discarded first. Thus, a median value for DSCP is recommended.
IEEE 802.1Q
The VLAN tag defines the priority for Ethernet frames and the VLAN ID based on IEEE
802.1p/Q. The IP Phone PC and LAN (voice) ports use separate VLAN tags. With a VLAN ID
assigned, only frames with the Id are accepted and frames sent by the IP Phone include the
LAN port Id and priority. In addition, the PC, LAN switch ports and the default gateway must be
assigned to employ the VLAN tags for proper operation.
Jitter Buffer Configuration
A jitter buffer stores incoming packets to allow for re-sequencing out-of order packets. The
Jitter Buffer configuration controls the size of the buffer used. The minimum, normal and
maximum delays expected can be changed. Using larger values produce less packet loss as
the IP Phone waits longer to receive packets before processing. Note that large values may
delay voice packet processing and smaller values may produce more packet loss but quicker
voice packet processing.
To modify the QoS configuration:
Select the parameter and either enter a new value or select a value from the drop-down menu.
When complete, select
to load the new values in the IP Phone memory.
Modifications made to the IEEE 802.1p/Q configuration require a reboot of the IP
Phone. When you leave the menu, you will receive a Reboot notice. The IP Phone
must reboot to utilize the new values entered.
