LDP messages All LDP messages have the following format. U Message type Message Ienght Message ID Parameters LDP Message format U The U bit is an unknown message bit. Message type The type of message. The parameters contain the TLVs. There are both mandatory and optional parameters.
Some messages have no mandatory parameters, and some have no optional parameters.
The U bit is an unknown TLV bit. F Forward unknown TLV bit. Type Encodes how the Value field is to be interpreted. Length Specifies the length of the Value field in octets. Value Octet string of Length octets that encodes information to be interpreted as specified by the Type field.