Understanding UDP

Discover the steps you need to take to send log data to ElasticSearch via UDP in this help article from Logit.io.

Chris Cottam avatar
Written by Chris Cottam
Updated over a week ago

What is UDP?

The two most common network transmission protocols are TCP (transmission control protocol) and UDP (user datagram protocol).

TCP is often used for traffic where guaranteed delivery is more important than the speed of delivery and includes protocols to confirm that traffic has been delivered or not. Examples include HTTP and most non-live streaming traffic.

UDP doesn't offer the same delivery guarantees and is often used in situations where speed of delivery is more important than being able to retry a failed delivery.
Examples include VOIP traffic where minimising the latency is more important, or DNS traffic where minimising the overhead is valuable.

What are there risks to sending logs via UDP? 

UDP can offer faster delivery due to the reduced overhead and may be a reasonable choice for transferring logs over a local network where packet loss is unlikely. 

On a large/global network like the internet, some/occasional packet loss can reasonably be expected. This may result in logs failing to be delivered to your stack successfully.

Why is UDP even supported then?

UDP support for shipping logs is largely there for legacy reasons. We would advise a customer to choose an encrypted log shipping method whenever possible.

What's next?

  • Learn about sending logs using UDP

  • Learn about sending logs using TCP

  • Learn about sending logs using Filebeat

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