Apple Time Capsule related technical question.
In short, - does there exist a way to disable at the Time Capsule the SMB signing feature?
Regarding the original SMB1 protocol, the signing mechanism is slowing down the overall performance extremely. For example, writing to the Time Capsule network share is over a Gigabit LAN connection at around 15 MB/s and goes down to around 2 - 3 MB/s when a lot of smaller files are transferred.
This behavior is SMB1 related and is therefore present on different operating systems and (older) NAS network devices. Newer SMB2+ versions have a different, more efficient, design which results in much reduced overhead in conjunction with the signing feature. I can confirm this for several older Windows 7 computers where their (SMB2 based) network shares can handle transfer speeds up to 100 MB/s.
The usual solution is to disable the SMB signing. This can be done on macOS (and other OS) quite easy: https://dpron.com/os-x-10-11-5-slow-smb/
In my case, however, it is somewhat more complex. Regarding the Time Capsule -- I had to do this at the "server side" which is effectively the Time Capsule. I have experimented to deactivate the signing at the client side (Mac OS, Windows 7) but it shows no effect. The SMB1 network share speed is always very slow because the SMB1 signing remains active.
So, my idea is to find a BSD command which deactivates the signing at the Time Capsule. The earlier Time Capsule models (up to the fourth generation) are NetBSD 4.0 based. The last model, the fifth generation, is based on NetBSD 6. There exists a non-official way to access the Time Capsule through SSH. ;-)
And finally, a switch to the Apple AFP protocol is not a real solution because the Time Capsule share is also used under Linux and Windows. AFP is therefore only a solution for macOS based systems. However, Apple itself regards AFP as deprecated. It is no longer supported with the new APFS file system. Apple uses for APFS based network shares newer SMB versions.