I'm designing a P2P system. I need to decide an ideal packet size that maximizes the efficiency of my system. This answer claims a 508 bytes is the maximum safe size, but I believe larger packets should also have low drop rates in modern equipment. I wonder what is a reasonable size in practice, today. Is there any research tracking drop and fragmentation rates across multiple routes in different places based on packet size?

  • Regardless of size, you will lose UDP datagrams because UDP is connectionless with no guarantees. You either need to build tracking and resending into your application, or you need to use a protocol, e.g. TCP, that provides guaranteed delivery.
    – Ron Maupin
    Aug 3, 2021 at 19:53

1 Answer 1


There is no general rule - some networks pass packets up to the over-standard-Ethernet MTU (1500 bytes), some don't. 508 bytes for UDP payload is derived from the minimum MTU of 576 bytes and looks plausible - but is not efficient.

The ideal way to deal with this - for maximum efficiency - is to make your system support variable datagram sizes and use path MTU discovery (PMTUD) to select the optimal size. It's fairly simple really.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.