Handshaking; Throughput; Selective Reject - 3Com Courier Reference

13

Handshaking

Selective Reject

H
ANDSHAKING
DATA COMPRESSION

THROUGHPUT

This chapter contains information about:
Handshaking
Selective Reject
V.90 Capabilities
Error Control
Data compression
Getting maximum throughput
With each call, Courier V.Everything modems go through a link
negotiation process with the remote device. Another name for the
negotiation process is "handshaking.
Courier V.Everything modems default to V.90 modulation and try for the
highest possible speed when they attempt to connect with another
modem: 56 Kbps. If the remote device is not V.34-capable, a connection
is made using the highest compatible modulation scheme (x2, V.34, V.FC,
V.32 terbo, V.32 bis, and so on, down to as low as Bell 103, or 300 bps).
The Courier V.Everything modem supports Selective Reject for analogue
calls. Selective Reject improves performance on noisy lines by reducing
the amount of overhead incurred when the protocol must resend data
due to errors
When Selective Reject is active, only the frame that contained the error is
resent, instead of the frame plus all of the following unacknowledge
frames.
,
ERROR CONTROL
,
AND
,