Default number of anounces sent by uftp

[David]

Hi,

By default uftp sends 10 file announces.

In case a list of clients is defined, when all clients listed have replied, no more announces are sent. This greatly speeds up the startup process.

Would it be possible to reduce the default number of announces? This would greatly speed up the startup in case one receiver is not answering. If the receiver is not answering to the first announce, it is very likely it will not answer to the other one, which means that the waiting time is quite useless, at least in my case.

I could not find any corresponding option switch for uftp. Nor the variable handling this in the code.

Thanks in advance for your help with this,
David

[Dennis Bush]

The robustness factor option (-s on the server) controls how many times the server will retransmit certain messages. This includes ANNOUNCE as well as KEYINFO, FILEINFO, and DONE. It also controls certain timeouts on the client side. This value can be set to as low as 10, however be aware that this increases the chance of a timeout occurring on either side.

[David]

Thanks for this answer.

Actually, I would like to set it to 3 or so for number of ANNOUNCE.

I am using closed group membership (-H switch), but whenever one client goes offline, all my file transfers are delayed by 10 seconds, which is quite annoying.

I know I would do this to my own risk, but can you see potential difficulties when forcing uftp to allow robust < 10 ?

For example making changes here:
/uftp-4.6/server_config.c: if ((robust < 10) || (robust > 50)) {

Thanks in advance for your feedback,
David

PS: But the best would be to have a uftp release doing this job for me ;)

[Dennis Bush]

Since the robustness factor also controls how many times a DONE message is sent when the server is at the end of a pass, if any clients are lagging behind then setting robust = 3 will greatly increase the chances that these clients will get dropped. If congestion control is turned on, this also increases the chance that the CLR (the receiver who is allowed to respond immediately to CONG_CTRL messages) will be reassigned resulting in more rate changes.

On the client side, the robustness factor controls how much inactivity from the server will be tolerated before it aborts the session.

If you want to change the minimum allowed robustness factor in your environment that's fine, just be aware that you'll increase the likelihood of dropped sessions.

[Generic name]

Hi,

I'm just weighing in here that it would be really great if UFTP could include a switch for number of initial announcements that is completely separate from the robustness switch ... As in I want to keep robustness at 20 but announce as 5

I have UFTP working great over a high latency link, but with many millions of files to send the longest part now is waiting for the announces to time out...

Some other items on a wishlist/feature request:

• file stream compression option (e.g. gzip) - i send lots of compressible data but scripting the compression/decompression is difficult

• MD5 (or SHA/crc32 etc etc) hash check after file has been transferred to verify its identical / no corruption

Great software though! Your the cheapest and quickest fix to lack of wan optimization over a VPN i've found !