l2tpv3 bridge & slow performance

I am testing a l2tpv3 bridge between two data centers. I have successfully configured the bridge and passed traffic through; however when doing transfers they will pause and then resume throughout the copy. The files transfer does complete, but it the start/stop behavior slows down the process.

I have been able to confirm that the WAN links are stable as transfers over it that do not utilize the bridge are successful.

Any ideas?

My guess is you are trying to use Samba/CIFS (Windows file transfer)?
It’s horrible on internet links, so Microsoft started BranchCache.
(What's New in BranchCache | Microsoft Learn)

For example, I get about 8Mbps on Windows File transfers, but around 20Mbps on iperf3 going from two OVH servers 1 in RBX (France) and 1 in BHS (Canada).

I just went ahead used GRE, works without a problem.