Precedence, Preemption and the Ietf

Abstract

The Internet Engineering Task Force (IETF) is the primary standards organization for evolution of the Internet architecture and Internet operation. The Internet has supported an ever-changing set of applications by remaining largely agnostic to the information content of the packets transported across the network without resource reservations or preferred treatment. This works because most applications are "elastic" and react to congestion by slowing their sending rate. By default, all information transfers are treated equally. This basic design did not consider application requirements (e.g., Quality of Service) or the mission importance of certain connections (i.e., a Class of Service [CoS] where some transactions are deemed of greater importance than others). However, all information flows are not equal in a military environment, and hence, the military community is taking these requirements to the IETF. While theoretically the IETF's standards are developed for the public Internet, in practice some protocols will be deployed exclusively over private Internet protocol networks such as the global information grid (GiG). The Internet Emergency Preparedness Working Group (IEPREP) has specifically focused on requirements for emergency telecommunications for situations where some communications are vital. For example, IEPREP has produced requirements for session initiation protocol (SIP) to carry priority information, which, in turn, has lead to RFC 4412. SIP facilitates sessions to be set up and with RFC 4412, the protocol can also relate information on CoS, analogous to the Multi-level Precedence and Preemption (MLPP) indication available on some existing military networks. However, there is a much greater problem to be solved; unlike circuit-switched networks, signaling and transport resources are not tightly coupled. Hence, to solve the issues of precedence and preemption will require new architectures; where there are insufficient network capabilities in the underlying network to support such a new architecture, the IETF is the logical organization to develop them