Packet format

All OLSR traffic is sent in OLSR packets. These packets consist of a OLSR packet header and a body as displayed in fig 3.1.

Figure: The generic OLSR packet.

The fields in the OLSR packet header are:

• Packet Length - The length in bytes of the entire packet, including the header.

• Packet Sequence Number - A sequence number incremented by one each time a new OLSR message is transmitted by this host. A separate Packet Sequence Number is maintained for each interface so that packets transmitted over an interface are sequentially enumerated.

An OLSR packet body consists of one or more OLSR messages. OLSR messages use a header as shown in fig 3.1. All OLSR messages must respect this header. The fields in the header are:

• Message type - An integer identifying the type of this message. Message types of 0-127 are reserved by OLSR while the 128-255 space is considered ``private'' and can be used for custom extensions of the protocol.

• Vtime - This field indicates for how long after reception a node will consider the information contained in the message as valid. The time interval is represented in a mantissa-exponent format.

• Message Size - The size of this message, including message header, counted in bytes.

• Originator Address - Main address of the originator of this message.

• Time To Live - The maximum number of hops this message can be forwarded. Using this field one can control the radius of flooding.

• Hop Count - The number of times the message has been forwarded.

• Message Sequence Number - A sequence number incremented by one each time a new OLSR packet is transmitted by this host.