Enabling encryption causes an occasional bad bytes

I am using a Digi Connect SP to send some simple serial data across the network. On my Windows laptop, I am using Realport to receive the data.

It works great! It runs for hours and everything works fine.

But I want to enable encryption. When I do this, it works mostly fine … but about once a minute I will get some kind of “garbled” data through RealPort. This doesn’t happen when encryption is off!

I know this because the data should come across in a very specific format (so my code can understand it). But when encryption is enabled, my code sees errors in the data format (about once a minute).

Any tips here?

I did a bit more digging and discovered that when I turn on encryption, it causes serial overflow errors. I confirmed this by telneting to the device and running the “serial info” command.

It seems like encryption reduces the max throughput. Can someone point me to a document where the throughput reduction caused by encryption is documented?