Fourcault process the pit must be "heated back" and then the process can continue anew. Glass chemistry has a huge impact on the process since it controls the melting, forming and annealing temperatures, liquidus temperature (point where various chemicals that make up the glass start to crystallize out of the glass) and rates of change of characteristics of the glass itself. Occasionally the ribbon will break or crack, leading to failure of the drawing process. Such breaks, known as "checks" can be alleviated by using proper operating parameters. Sometimes an expedient measure, using a portable source of heat, can be used to
Traffic shaping such cases per-client traffic shaping is more effective without creating potential controversies about what traffic is being controlled. To ISPs, mere protocol identification (classification) gives the intangible yet significant benefit of seeing what internet traffic is flowing through the network. From this they can see which subscribers are doing what on their network and can target services to the subscriber base they have attracted. However, as time progresses, more and more protocols are using tunneling and encryption to defeat these methods. Also, many protocols are very difficult or impossible to detect. In such cases, per-client shaping is more effective. By