proc ConfigLicenseServer {{licenseServerIp None} {licenseMode None} {licenseTier None} } {
    # licenseServerIp: The license server IP.
    # licenseMode: subscription | perpetual| mixed
    # licenseTier: tier1 | tier2 | tier3 ...

    if {$licenseServerIp != "None"} {
	puts "\nConfiguring license server: $licenseServerIp"
	if {[catch {set status [ixNet setAttribute [ixNet getRoot]/globals/licensing -licensingServers $licenseServerIp]} errMsg]} {
	    puts "Error: ConfigLicenseServerIp: $errMsg"
	    return 1
	}
    }
    if {$licenseMode != "None"} {
	puts "Configuring license mode: $licenseMode"
	if {[catch {set licenseServer [ixNet setAttribute [ixNet getRoot]/globals/licensing -mode $licenseMode]} errMsg]} {
	    puts "Error: ConfigLicenseMode: $errMsg"
	    return 1
	}
    }
    if {$licenseTier != "None"} {
	puts "Configuring license tier: $licenseTier"
	if {[catch {set licenseServer [ixNet setAttribute [ixNet getRoot]/globals/licensing -tier $licenseTier]} errMsg]} {
	    puts "Error: ConfigLicenseServerIp: $errMsg"
	    return 1
	}
    }
    ixNet commit
    return 0
}