4-12
C
HAPTER
4: C
ONFIGURING
THE
3C509B NIC
For example, for video conferencing with three people,
applications use three UDP streams for the video data. The
value must be a power of two (2, 4, 8), but the optimal
value varies depending on the PC and application.
A video server can support 32 connections but a client may
only want to conference with four other people at a time.
A value of 16 is recommended for most applications.
Low-Priority Ratio
When PACE support is enabled,
high-priority packets are always transmitted before
low-priority packets. If a certain high-priority application
sends out enough packets, no low-priority packets may
get sent.
To prevent this problem, the driver uses a ratio value to
periodically send out a low-priority packet (if one is
waiting to be sent).
For example, if a value of 1000 is entered, one low-priority
packet would be sent for every 1,000 high-priority packets.
A value of 25 is recommended for most applications.
Natural Packet Interval
To communicate packet
priority to the interconnect devices (repeaters, switches,
etc.), the PACE driver slightly modifies the Ethernet packet.
When these modified packets are sent out for long periods
without any low-priority packets being sent, connection
problems may result.
For this reason, the driver can be configured to send out
an unaltered, natural packet periodically. The value given
is in seconds.
A value of 180 seconds (3 minutes) is recommended for
most applications.