Hi, Martin.
I assume that you are talking about GravityChannel which is used for Push messages and also internal GraniteDS information transfers via this type of channel.
As far as I see during my work with GraniteDS. There are at least 3 operations that will be always sent via this channel.
1. Granite will send Ping operation to ensure that server is reachable.
2. Granite will send Subscribe operation which will subscribe client to the particular node (if it is in a cluster).
3. Granite will send Connect operation. The http request for this operation will be opened until there are some pending messages except Connect operation.
As far as I see this request is using async mechanisms and if your APP server doesn't support Servlet3 - you will be facing some issues. For example, if this request fail by timeout - then you will have to relogin when you client reaches @PreAutorise method.
At this point I haven't seen any multiple async requests.
Here is what I see in my working app. It uses GraniteDS and JMS Push mechanism. It is all working on Weblogic 12c. Pending http request - is Connect Operation about which I was talking. Hope I spread some light on your question..