3Com XLPCI manual Option Descriptions, Low-Priority Ratio, Natural Packet Interval

B-2APPENDIX B: CONFIGURING ADVANCED PACE OPTIONS

Although a video server can support up to 32 connections, a client may want to conference with only four other people at a time. The recommended setting is 16.

Low-Priority Ratio

When PACE support is enabled, high-priority packets are always transmitted before low-priority packets. If a high-priority, PACE-supported application sends out a sufficiently large number of high-priority packets, then low-priority packets from other PACE-supported applications may not be sent.

To prevent this problem, the PACE driver uses a ratio setting to periodically send out a low-priority packet (if a low-priority packet is waiting to be sent). For example, if a value of 100 is entered, one low-priority packet would be sent for every 100 high-priority packets. The recommended setting is 25.

Natural Packet Interval

The PACE driver slightly modifies the Ethernet packet to facilitate communication of packet priorities to interconnect devices (repeaters, switches, and the like). Consequently, connection problems may result when these modified packets are sent out for long periods, during which no low-priority packets are sent. To get around this problem, the PACE driver can be configured to periodically send out an unaltered, natural packet. The recommended setting is 180 (seconds).

Option Descriptions

The following advanced options can be enabled or disabled to regulate packets.

Disable Switch Packet Prioritization

This option disables modification of Ethernet packets used for prioritization of multimedia traffic within 3Com switch products. For example, disabling switch packet prioritization can sometimes prevent multimedia-connection failures between a PACE-enabled workstation and a non-PACE workstation.