Packet sequencing: a layer-2 WAN switching technology for per-flow ideal QoS and secure IP networking

Viewing the Internet as simply a best-effort, unreliable datagram network has recently given way to new, more-demanding service expectations, driven in part by the goal of multiple services delivered via a single converged IP infrastructure. However, the associated goals of an ultimate quality-of-service (QoS) that support real-time and mission-critical applications, along with utmost security and reliability, remain elusive. This paper describes a fundamental technological advance that not only attains ideal QoS with unique security and reliability capabilities but also supports full interworking with traditional IP networks, inasmuch as it does not require modification (e.g., labeling) or higher-layer/proprietary interpretation of IP packets. We describe an advanced wide-area network composed of traditional end-points, dual-mode switch/routers, and sequencing agents that provide per-flow admission and scheduling of packets on a link-by-link basis from source to destination. The network is fully scalable and can readily provide reachability across multiple domains that span the globe. Sequencing agents assure an individual, time-deterministic path for every critical application-i.e., those that require minimal transport delay (i.e., no packet queueing), no jitter and no packet loss. Moreover, since sequencing is accomplished on a per-flow basis and invokes a temporal paradigm for packet switching, we show that applications are completely immune to extraneous network influences, notably network congestion or Denial-of-Service attacks. As discussed in this paper, commercial-off-the-shelf (COTS) equipment realization has demonstrated these attributes for both customary realtime flows (examples of which include voice- and video-over-IP) and sequenced TCP flows. The latter is especially significant, in that it makes possible for the first time a system for fully managed and guaranteed throughput of TCP data while maximizing goodput, a significant advance for reliable, deterministic, secure data transmission and networked storage. This paper further makes clear that traditional end-points (e.g., videoconferencing units and IP phones) can readily operate in packet-sequenced networks. Moreover, we note that the sequencing protocol permits per-flow reuse of preallocated-but unused-throughput. Consequently, nonsequenced packets (e.g., best-effort, asynchronous data) are "backfilled" and amenable to conventional routing in either sequenced networks or interconnected, conventional IP networks, thereby providing facile interworking with the large embedded base of legacy IP equipment.