Does anyone know the underling network protocol that is used between host and client for the shipping of binary files from:

  • OneDrive
  • Google Drive
  • DropBox
  • iCloud

I suspect the answer is some variant of WebDav. But I suspect they may be doing some optimizations for incremental updates, and I would like to understand that. Does anyone have a clue how they do it? What sort of polling for updates do they do to minimize net traffic & server load?

  • 10
    Let me just quickly state that it is appreciated that you came to meta to ask. Every time we get to explain why something is or isn't on topic is one less close vote, and hopefully one less frustrated user.
    – Reaces
    Dec 2, 2016 at 7:04
  • 1
    Microsoft has documented a significant portion of their protocols for interoperability. The same is unlikely to be true for the others (at the time of this writing) and the previously suggested network capture is likely your best bet. To get you started, you can see an example of a Microsoft protocol document detailing BITS upload of large files to OneDrive. https://msdn.microsoft.com/en-us/library/dn858877.aspx You can search from there for other protocol documents, including BITS itself. Dec 13, 2016 at 20:33
  • Thanks Matthew, do you have any gut feeling if BITS would be slower than a custom tcp stack as is used by Aspera, which our US government clients really love.
    – Dr.YSG
    Dec 14, 2016 at 18:58

1 Answer 1


No, this is not on-topic. You're a user of those services, not an administrator of them.

That said, it's trivial to perform a packet capture (with an SSL bump proxy) to examine the protocols involved on your own, which is something you should do.

  • 1
    Maybe just your first sentence makes sense. What has his/her relationship to the service got to do with anything. How is triviality relevant anyway? You mean when it is or is not trivial his questions becomes on or off topic?
    – Chris
    Dec 2, 2016 at 18:49
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    @Chris The OP's relationship with the service is relevant due to the charter of Server Fault. If this person was in charge of running the services mentioned, it would be on-topic. Of course, if this were the case, the person would not be asking this question. As to my last sentence, this is something that any network or sysadmin should know how to do. I'm a strong believer in not spoonfeeding people step-by-step instructions on how to do things. One learns better when they have to put thought and effort into whatever it is they're learning. So I dropped hints as to what the OP should do.
    – EEAA
    Dec 2, 2016 at 19:00
  • I agree with you one hundred percent about not spoonfeeding.
    – Chris
    Dec 2, 2016 at 19:34
  • So where should this be posted? Super User?
    – mlhDev
    Dec 7, 2016 at 12:15
  • My best bet would be Stack Overflow, but it may be too broad for a question. It may be better to find the customer support for each service. Dec 7, 2016 at 15:37
  • It's not a programming question, so I'd say Super User. Dec 12, 2016 at 15:00

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