What Is The Payload?

Date First Published: 1st May 2022

Topic: Computer Networking

Subtopic: Data Transmission Technologies

Article Type: Computer Terms & Definitions

Difficulty: Advanced

Difficulty Level: 8/10

CONTENTS

Payload Limits

Learn more about what the payload is in this article.

The payload refers to the data that is within a data packet and the only data that is received by the destination system. It is encapsulated in a frame format and is made up of framing bits and a frame check sequence, such as Ethernet frames. It does not include the generated metadata or the header information, which identifies the source and destination of the packet. This information is removed from the packet when it reaches its final destination as it is only used in the transmission process.

Note:

The term 'payload' comes from transportation, where it refers to the part of the load that 'pays' for transportation.

Payload Limits

Payload limits are important as they determine the performance of a protocol. Smaller payloads mean that more data packets need to be transported for large amounts of data and larger payloads mean that fewer data packets need to be transported for large amounts of data. High speed and reliable networks are required for larger payloads.

The payload limit can be calculated by subtracting the required amount of data from the headers and trailers from the maximum transmission unit size of the protocol. The RFC 791 specification states that all sending and receiving devices must be capable of accepting data packets with a maximum size of 576 bytes, a payload of 512 bytes, and a header of 64 bytes. The maximum transmission unit depends on the device and network.

The total length field in the data packet header, which is 16 bits long limits the maximum payload size for data packets. This means that the maximum length of a data packet is 65,535 minus the number of bytes that are required for the payload header.