def checkProto(proto)
            if proto != Protocol::UDP && proto != Protocol::TCP then
                raise ArgumentError, "Unknown protocol #{proto}, only Protocol::TCP and Protocol::UDP are valid."
            end
        end
def checkProto(proto)
            if proto != Protocol::UDP && proto != Protocol::TCP then
                raise ArgumentError, "Unknown protocol #{proto}, only Protocol::TCP and Protocol::UDP are valid."
            end
        end
Check that the protocol is a correct value