Description

The issue occurs when both instances have a significant difference between their last sent and last ack'd sequence number, as they will begin waiting for the sequence history to be flushed for a packet. While they wait for this ack, they will reject incoming packets, causing them to stop sending acks for received packets. With both instances doing this, neither will receive an ack for the sequence number they're waiting on.

Steps to Reproduce

Issue seems to occur rarely under poor networking conditions, particularly when bandwidth is being throttled. With significant latency, packet loss, and bandwidth limiting, a client and server sending a high amount of traffic between each other can end up in this state.

Have Comments or More Details?

There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-317903 in the post.

0
Login to Vote

Unresolved
CreatedSep 4, 2025
UpdatedSep 5, 2025
View Jira Issue