UE 5.6.1 causing extremely high UDP traffic

TheGameAssembly
Tue, 21 Oct 2025 14:58:12 +0000
Getting Started & Setup

Since around the 25th of September this year we have several classroom machines running UE 5.6.1 which constantly spam UDP messages through the network. Around 97% of our total network capacity is being consumed by this traffic, around 9 gbit, which is of course causing quite a lot of problems.

When tracing the packages it seems the machines are sending ChaosVDSessionPing and ChaosVDSessionPong messages between one another at the rate of about a 1000 a second per machine.

This does not happen on all machines running this particular version but the majority of the 50 or so users that run UE daily have this problem. When they all shut down UE the traffic stops like clockwork.

At the same time this error appeared nearly every time they save their work:

/Game/OurLevels/Level_1 Validating asset
/Game/OurLevels/Level_1 Validating asset
/Game/OurLevels/Level_1 Validating asset
/Game/OurLevels/Level_1 Warnings logged while validating asset FUdpMessageProcessor::UpdateReassemblers Discarding 2/4 of stale message segements from Sender=10.xxx.xxx.xxx:57559, Sequence=0
FUdpMessageProcessor::UpdateReassemblers Discarding 3/4 of stale message segements from Sender=10.xxx.xxx.xxx:57559, Sequence=0
FUdpMessageProcessor::UpdateReassemblers Discarding 3/4 of stale message segements from Sender=10.xxx.xxx.xxx:57559, Sequence=0
FUdpMessageProcessor::UpdateReassemblers Discarding 3/4 of stale message segements from Sender=10.xxx.xxx.xxx:57559, Sequence=0
FUdpMessageProcessor::UpdateReassemblers Discarding 3/4 of stale message segements from Sender=10.xxx.xxx.xxx:57559, Sequence=0
FUdpMessageProcessor::UpdateReassemblers Discarding 3/4 of stale message segements from Sender=10.xxx.xxx.xxx:57559, Sequence=0
FUdpMessageProcessor::UpdateReassemblers Discarding 3/4 of stale message segements from Sender=10.xxx.xxx.xxx:57559, Sequence=0
/Game/OurLevels/Level_1 Validating asset
/Game/OurLevels/Level_1 Validating asset
/Game/OurLevels/Level_1 Validating asset
/Game/OurLevels/Level_1 Validating asset

which we are not sure is related but it could be, and started happening at the same time.

Any help or suggestion would be appreciated. We do not run any in-house plugins or other code, nor do we build the engine ourselves. This is stock standard UE from the EGL.

8 posts - 5 participants