May be – I hoped rules about software allowed on personnel notebooks should be better defined in non-academic environments )).

I’d also, however, wonder about the eventual consequences to bandwidth of forcing all UDP to be converted to TCP. It seems like it would eventually defeat any purpose involving conservation of bandwidth.

TCP is not only about acknowledgment of packets arrival and retransmission of lost packets, it is much more about self-regulation – if a peer (in TCP connection) doesn’t receive couple of ACK’s, it decreases the rate of sending and this is built in the OS TCP stack, not in torrent (or any other) client. So a fall-back to TCP really alleviates the bandwidth problem even without any traffic shaping (btw, the first time I experienced the UDP problem and its TCP alleviation was about 12yrs ago, when a guy in our campus “experimented” with an outbound X11-session over 119 Kbit line and saturated it… after being warned and some bitching about our “mostly incoming activity” he switched to ssh X11 forwarding, and problem was solved).

I’d expect to run into it outside of academia as well.

I’d also, however, wonder about the eventual consequences to bandwidth of forcing all UDP to be converted to TCP. It seems like it would eventually defeat any purpose involving conservation of bandwidth. Maybe not.

Anyway, I definitely agree with keeping TCP fall-back in mind. That especially depends upon the environment within which the application must run. It’s one thing to create an app that’s intended for local users; it can be very different when there are totally unknown network segments to cross.

Tom

Now, from a sysadmin point of view – recently, torrent clients switched to UDP and, at least in an academic environment like ours , several student’s notebooks are able to saturate the outgoing link. So now, all UDP except DNS (p. 53) and NTP (p. 123) is forbidden and torrent clients (un?)happily fall-back to TCP. In such environment an UDP-based chat program will not work in spite its traffic requirements are very small (e.g., all-UDP based old Skype clients are not working; newer, which can fall-back to TCP are operative) .

So, if you decide to have UDP functionality, better make a provision for TCP fall-back.