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Big Window TCP ( btcp)

 

An adaptation of BSD Lite's Big Window TCP. Big Window TCP is an implementation of a TCP extension that allows send windows greater than 64KB in size. See RFC 1323 for more information on Big Window TCP. The following arguments for btcp may be specified on an args or pargs line.

-tcpAcknow

If this option is specified, the protocol acknowledges every segment. The default is to send an ACK for every 2nd segment, or upon expiration of the fast timeout.

-tcpSlowstart=<integer>

Specifies the size of the window, in segments, at the beginning of slow start. The default is 1. This option is included for experimental purposes.

-tcpTimer=<integer>

Specifies a delay, in microseconds, before starting the TCP fast and slow timeouts. Without some timer delay, all hosts in a simulation will experience timeouts simultaneously -- this could lead to strange simulation results. The preferred alternative to manually specifying a different delay for each host is to use -tcpTimerAuto.

-tcpTimerAuto

Instructs the simulator to stagger the start delay for the timers on each host. If the duration of a timer is t, and there are n hosts, the hosts' timers are started at intervals of t/n milliseconds. For example, the fast timeout fires at intervals of 200 ms. If there were four hosts, their fast timeouts would be started after delays of 0, 50, 100, and 150 ms. Thus, every timer is given a unique start delay.

-tcpTrace=<integer>[:<integer>]

Trace events of importance to TCP, such as the transmission of a segment, the size of the send window, and the firing of a timeout. The function of the arguments is the same as with the

-ethdTrace option. (See Section 3.5.2.)



Larry Peterson
Mon Jun 24 16:40:03 MST 1996