3Com 1005 - page 66

DUA1840-0AAA01
Switch 1005 Setup 3-5
■ Fragment Fre e — In this mode, a minimum of 64 bytes of the
received frame is buffered prior to the frame being for warded. This
ensures that collision fragments are not propagated through the
network, however, CRC errors are forwarded. The forwarding delay
or latency for all frames in this mode is 64µs.
■ Store and Forward — In this mode, received packets are buffered in
their entirety prior to forwardi ng. This ensures that only good frames
are passed to their destination. The forwarding delay for this mode
varies between 64µs and 1.2ms, depending on frame length. In this
mode the latency, measured as the time between receiving the last
bit of the frame and transmitting the first bit, is 8µs.
■ Intelligent — In this mode, the Switch 1005 monitors the amount of
error traffic on the network and changes the forwarding mode
accordingly. If the Switch 1005 detects less than 18 error packets per
second, it will operate in Fast Forward mode. If the Switch 1005
detects more than 18 packets per second it will operate in Store and
Forward mode until the number of error packers per second returns
to 0.
PACE Enable/Disable This field allows you to enable or d isable PACE
(Priority Access Control Enabled) for all por ts on the Switch 1005.
Enabling PACE on a port increases network performance, especially if
you are running multimedia applications. The rules for enabling PACE
are:
■ PACE should only be enabled on ports that connect to a single
end-station, switch, bridge or router
■ You should not enable PACE on a port connected to a repeater
■ If you have PACE-equipped devices at both ends of a link, PACE
should only be enabled on one of the devices