Abstract: In one embodiment, a distributed environment for supporting on-line collaborative meetings among a plurality of users includes a plurality of applications executing on different client machines. A sequence of messages is transmitted from a first application of the distributed environment to a second application of the distributed environment, using a multicast form of delivery. A request for re-transmission is received from the second application specifying at least one message of the sequence that was not received by the second application. In response to the request, the specified at least one message of the sequence is retransmitted from the first application to the second application using a reliable unicast form of delivery.

Abstract: An apparatus, method and computer program product for emulating a persistent connection using http. According to one embodiment, the method includes receiving an empty get from a first client; receiving a get from a second client, the get containing data to be sent to the first client; and sending a response to the first client, in response to the empty get, the response containing the data. According to another embodiment, the method includes receiving, from a client, a get containing first data to be sent to an application server; sending the first data to the application server; sending an ack response to the client in response to the get; receiving a response from the application server, the response containing second data to be sent to the client; waiting for an empty get from the client; receiving an empty get from the client; and sending the second data to the client in response to the empty get.