OCI's Middleware News Brief (MNB) features news and technical information about open source middleware technologies (e.g., TAO, OpenDDS, JacORB, OpalORB), including case studies and other technical content.
DDS (Data Distribution Service) is an OMG standard and a potentially excellent technology for the (Industrial) Internet of Things (IIoT), since it allows developers to create robust, secure, and interoperable distributed applications by providing publish/subscribe semantics to a shared cache.
Interoperability for DDS applications is achieved by using the Real-Time Publish Subscribe (RTPS) protocol. However, the discovery procotols in RTPS assume that the underlying network supports multicast and that datagrams are not subject to network address translation (NAT). Both of these assumptions are violated in a typical IIoT application. Thus, in order for DDS and RTPS to become viable technologies for IIoT, we must expand the reach of RTPS to include networks where multicast is not supported and packets are subject to NAT.
This article presents a solution to these problems by introducing a service that relays RTPS messages.