The file lib/remote.exp defines procedures for establishing and
managing communications. Each of these procedures tries to establish
the connection up to three times before returning. Warnings (if
retries will continue) or errors (if the attempt is abandoned) report
on communication failures. The result for any of these procedures is
either -1, when the connection cannot be established, or the
spawn ID returned by the Expect command spawn.
It use the value of the connect field in the target_info
array as the type of connection to make. Current supported connection
types are ssh, tip, kermit, telnet, rsh, and rlogin. If the
--reboot option was used on the runtest command line,
then the target is rebooted before the connection is made.