The structure of a data packet in RIP (Routing Information Protocol) can be divided into two parts: the header and the data section.

Header block

The header of a RIP packet contains the following fields:

• Command: specifies whether the packet is a request or a response
• Version: indicates the version of the RIP protocol being used
• Must be zero: a reserved field that must be set to zero
• Address family identifier (AFI): identifies the type of address being used (e.g., IPv4 or IPv6)
• Must be zero: a reserved field that must be set to zero
• Must be zero: a reserved field that must be set to zero
• Must be zero: a reserved field that must be set to zero

Data block

The data section of a RIP packet contains a series of routing information entries. Each entry consists of the following fields:

• Address family identifier (AFI): identifies the type of address being used (e.g., IPv4 or IPv6)
• Route tag: a value assigned by the sender to identify the route
• IP address: the IP address of the destination network
• Subnet mask: the subnet mask associated with the destination network
• Next hop address: the IP address of the next hop router
• Metric: the number of hops to reach the destination network

RIP packets are sent between routers to exchange routing information and update their routing tables. RIP is a distance-vector routing protocol that uses hop count as the metric for determining the best path to a destination network. RIP packets are simple in structure and widely used for small to medium-sized networks, but have limitations for larger networks due to its hop count limit of 15.