...
Websocket API - Originally part of HTML5 specification. It provides two-sided communication with a remote host. It is now supported natively in Google Chrome.
CometD on a cluster:
- Cometd servers may be aggregated into a cluster using Oort, which is a collection of extensions that use the java CometD client to link the servers together. The Oort class allows cometd servers to observe each other, which means to open bayeux connections in both directions.
- Every comet server creates an instance of Oort which creates a BayeuxClient to connect to all other known comet servers (These URLs must be passed to the Oort object during instantiation). It then adds listeners to whatever channels it is interested in. Thus, each server communicates both ways with each other server in the cluster.
- There is a special set of channels, "/oort/*" for cluster communication. There is a special channel called '/oort/cloud' on which comet servers can broadcast the URLs of comet servers they know of.