Hessian is a binary web serviceprotocol that makes web services usable without requiring a large framework, and without learning a new set of protocols. Because it is a binary protocol, it is well-suited to sending binary data without any need to extend the protocol with attachments.
Although Hessian is primarily intended for web services, it can be adapted for TCP traffic by using the HessianInput and HessianOutput classes in Caucho's Java implementation.