proc StartTraffic { {includeApplyTraffic apply} } {
    # Need to make apply traffic an optional parameter because
    # not every situation can except apply traffic prior to 
    # starting traffic such as packet capture.  
    # If apply traffic for packet capture, it will stop the packet
    # capture.

    set traffic [ixNet getRoot]traffic

    if {$includeApplyTraffic == "apply"} {
	if {[ApplyTraffic] == 1} {
	        return 1
	} 
    }

    puts "StartTraffic ..."
    for {set retry 1} {$retry <= 10} {incr retry} {
	catch {ixNet exec start $traffic} errMsg
	if {$retry < 10 && $errMsg != "::ixNet::OK"} {
	        puts "\nStartTraffic: Not ready yet. Retry $retry/10: $errMsg"
	        after 1000
	}
	if {$retry == 10 && $errMsg != "::ixNet::OK"} {
	        puts "\nStartTraffic: Failed: $errMsg\n"
	        return 1
	}
	if {$retry < 10 && $errMsg == "::ixNet::OK"} {
	        puts "\nStartTraffic: Traffic started\n"
	        break
	}
    }
    
    if {[VerifyTrafficState]} {
	return 1
    }
    
    return 0
}