On today’s Internet, people are used to seeing a lag when viewing videos from a distant location. Researchers have been working to develop methods that will smooth the transmissions, and reduce the delays and lags. The key components are called routers, which route data from the source to the destination through the maze that is the Internet. The packet transmission algorithms used inside the router to guarantee the quality of service have many variations. One of them is called integrated service, which involves reserving bandwidth for each connection along the transmission path. Another is called differentiated service, which bundles different connections into a single category of transmission, after which the integrated service approach is applied to the bundle.

While reserving bandwidth may lead to wasted resources if not used, bundling different types of traffic may also be difficult or unsuitable, since different connections usually have different requirements. A third method is called time-driven priority (TDP) with pipeline forwarding. This technique uses a global time reference to schedule the packets, and then the transmissions are pipelined.

This paper analyzes the TDP method in terms of timing uncertainties, and shows that TDP can be implemented using an off-the-shelf personal computer. However, in all of the implementations and illustrations, one common weakness is that TDP requires a timing reference that uses a global positioning system (GPS) or Galileo satellite. Most routers are located indoors, which can interfere with reception of the timing information from satellites.

But all of these complexities and hassles may soon be irrelevant. A promising new architecture called the software-defined network (SDN) is becoming very popular and looks very likely to become the major component of future networks. SDN can route and reroute traffic dynamically as needed. Furthermore, as fiber optic technology continues to advance and fiber is deployed at an unprecedented speed, this network lag may not be a problem much longer.