RIP packet format

The RIP packet format is displayed in Figure: RIP packet format.

Figure: RIP packet format

A RIP packet consists of the following fields:

• Command

  This field indicates whether the packet is a request or a response message. The request asks the responding system to send all or part of its routing table. The response may be sent in response to a request, or it may be an unsolicited routing update generated by the sender.

• Version

  This field indicates the RIP version used. This field can signal different potentially incompatible versions.

• Must be zero

  Not used in RIPv1. This field provides backward compatibility with pre-standard varieties of RIP. The default value is zero.

• Address family identifier (AFI)

  This field indicates the type of address. RIP can carry routing information for several different protocols. Each entry in this field has an AFI to indicate the type of address being specified. The IP AFI is 2.

• Address

  This field indicates the IP address for the packet.

• Metric

  This field specifies the number of hops to the destination.

• Mask

  This field specifies the IP address mask.

• Next hop

  This field specifies the IP address of the next router along the path to the destination.