proc StartPacketCaptureHlt { port } {
    # Must use low level API to start traffic. HLT doesn't work.
    # Enhancement is filed.

    puts "StartPacketCaptureHlt ..."
    set startStatus [::ixia::packet_control \
			 -port_handle $port \
			 -action      start \
			]
    if {[keylget startStatus status] != $::SUCCESS} {
	puts "\nError StartPacketCaptureHlt: $startStatus\n"
	return 1
    }
    after 10000
    return 0
}