Sequenced packet exchange definition

Sequenced packet exchange

(also SPX)

Sequenced packet exchange is a method of sending data in a specific order from one machine to another. This approach ensures data arrives in the correct sequence, even if some packets take longer to get to their destination. If any packets are lost or damaged, SPX detects this and will correct it. This data transfer method is ideal for file transfers or video streaming.

SPX was important for ensuring data was sent and received reliably, especially in older networks. But now, it’s not used as much because better and more popular networking methods have taken its place.

See also: data packet

How sequenced packet exchange works

First, data (e.g., a video file) is divided into small packets, each given a sequence number.
The sender (e.g., your computer) sends these packets to the receiver (e.g., your friend’s computer) over the internet.
Then, the receiver gets the data, and the packets are automatically arranged in the correct order using their sequence numbers.
If any packet is missing or arrives out of order, the receiver asks the sender to resend it. All of this happens in the background, without you or your friend having to be involved.
This process continues until all packets are received and arranged in the right order, ensuring the data is complete and in sequence.

Sequenced packet exchange benefits

It ensures data arrives correctly and in order — very important when sending files or having video calls.
It keeps data safe by preventing mistakes or damage.
If some data gets lost or damaged during sending, it helps to correct those mistakes by sending them again.
It manages how fast data is sent so that the internet doesn’t get too congested, ensuring everything works well.
SPX is widely supported in networking technologies and compatible with various software.
SPX helps keep video calls and online games smooth and lag-free, providing a great user experience.
In some cases, sequenced packet exchange can boost data security by checking that it’s received in the expected order and detecting any tampering.