[JDEV] File Transfer Proposals

David Sutton dsutton at legend.co.uk
Fri Feb 15 19:26:34 CST 2002

*nod* What the trick around that is that you basically put the file
somewhere, and simply send the person the url to collect the file from.
It keeps the traffic out of the xml stream, and better suited protocols
can be used for collection.


On Sat, 2002-02-16 at 02:10, Tom Jackson wrote:
> I have to admit that I have not looked much at the proposals but the
> main issue that needs to be addressed is that there is an internal limit
> on message size in Jabber. 
> For text messages, this limit is more than adequate. However, for a
> generic file transfer protocol inside jabber you need to deal with
> arbitrary file sizes.
> The current max limit is in the xml parser from what I have heard and it
> is around 1/2 megabyte. 
> This is a buffer limit I think, so a different protocol implimentation
> could have a lower limit, and some other part of the system could also
> have unanticipated limits that are not specified in the protocol.
> What would be most helpful is to have an application level protocol that
> would chop up the file and transfer it in less than MTU size chunks,
> possibly low enough to support udp. Each packet would have to specify
> the byte range, and maybe a sequence number, but I doubt the sending
> client would keep track of what packet was what, and would have to
> reconstruct based on byte range. 
> This would allow arbitrary sized file transfer, but also, it would allow
> clients to receive large files while still being able to chat. Otherwise
> most clients would probably handle the one large message until it was
> finished.
> --Tom Jackson
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