WebSockets - connection keeps closing after 1 minute

[WGH]

Hello!

My WebSocket connections keep closing after precisely one minute. 
The configuration is the same as provided in that commit comment.
http://trac.nginx.org/nginx/changeset/5073/nginx

Direct connections to the server (without intermediate nginx) happily live
for many hours.

What option should I change to fix that?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,236382,236382#msg-236382