ClearOne Communications
~ www.clearone.com
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Configuration
~ LAN Setup
LAN setup is required if you want to make H.323 calls, use the browser, or remotely
access the unit for administration and troubleshooting.
Optimal settings for LAN calls
The V-There requires appropriate settings on the network switches and hubs used for
H.323 LAN calls. For a 384kbps LAN call, V-There will require more than 800kbps of
LAN bandwidth (400kbps in each direction) due to overhead on packets. Equally
important is that packets must be delivered with minimum jitter and delay. The network
administrator can take several steps to optimize the performance of LAN calls:
•
Proprietary bandwidth control techniques on hubs and switches should be
turned off—they can reduce traffic on high usage ports.
•
Use switches rather than hubs, if possible—switches increase throughput.
•
Ports used for V-There should be configured as 10Mbit full duplex. Auto-sense
of duplex should be disabled.
•
Any proprietary packet forwarding algorithms designed to improve file transfer
and conventional IP usage should be turned off—LAN video calls need simple,
real-time packet delivery.
•
Good quality Cat. 5 cable should be used. Poor quality cabling will not cause
problems with normal operations as packets are re-sent, but on a LAN call,
lost packets will show up as blocky video or audible noise.
•
The network segments being used by V-There should not be heavily loaded with
other network traffic.
Video quality on the first call
During the first LAN call after initial setup, the V-There will attempt to detect the
half/full-duplex setting of the connected switch or hub. It looks for errors on the
Ethernet line. As errors can occur with the correct duplex setting, the V-There
measures them over a period of time, switches its duplex mode, and re-measures the
error rate. It then selects the best duplex setting. For this reason, the first LAN call on
a new installation should be left up for three minutes if the video quality looks poor.
The V-There is factory set to use half-duplex.
The unit monitors packet loss during the first call after each power-up. If packet
loss is excessive, the V-There will switch duplex settings and re-check the packet loss. If
the new duplex setting reduces packet loss, the new setting is retained. Under normal
circumstances, the second power up on the same hub results in minimal packet loss.
LAN Setup
LAN setup is not required
if you will use ISDN
exclusively.
✍
