Multi-Terabit/s IP Switching with Guaranteed Service for Streaming Traffic

Abstract

As traffic on the Internet continues to grow exponentially, there is a real need to solve transmission and switching scalability. Moreover, future Internet traffic will be dominated by streaming media flows, such as video-telephony, video-conferencing, 3D video, virtual reality, and many more. Consequently, network solutions will need to offer quality of service and traffic engineering together with the abovementioned scalability-i.e., over-provisioning is not likely be a viable solution to accommodate streaming media traffic. This paper describes the architecture of a ultra-scalable IP switch and the first experiments with a prototypal implementation. The switch scalability is a consequence of it operating pipeline forwarding of packets, which also results in quality of service guarantees for UDP-based streaming applications, while preserving elastic TCP-based traffic as is, i.e., without affecting any existing applications based on "best-effort" services. Moreover, the prototype demonstrates the low complexity of pipeline forwarding implementation as the deployed network gear was realized from off-the-shelf components in only nine months through the design, implementation, and testing efforts of the authors. I. THE PROBLEM The steady Internet growth over the past few years is impressive, but services so far deployed over the Internet are nothing compared to the ones that can still be deployed. One likely scenario is that the future Internet will be dominated by applications such as (3D) video on demand, high quality videoconferencing, distributed gaming, (3D) virtual reality, remote surveillance, and many more. These applications generate traffic that is either by nature streaming or can be effectively handled as such (e.g., large file transfers). Moreover, most of these applications need a minimum guaranteed quality in order to be usable. Consequently, there is a real need to solve scalability and traffic engineering simultaneously-specifically, without using over-provisioning in order to provide predictable service. Concerning scalability, it is interesting noting that Cisco's top-of-the-line router, CRS-1, has a per chassis switching capacity of 640 Gb/s (the announcement of 92 Tb/s is to be divided by 2, to avoid twice packets first entering and exiting the switch, and then by 72 chassis's), which represents an improvement over the Cisco 12000 by a factor of only 2 after 5 years of development-not the 18 months during which the Internet traffic doubles. This paper shows how the Internet can benefit from UTC-based pipeline forwarding of IP packets that enables (i) ultra-scalable IP switches-10-50 Tb/s in a single chassis, (ii) quality of service (QoS) for UDP-based streaming applications (as a bonus since a deterministic service is inherent to the switching solution itself), while (iii) preserving elastic TCP-based best-effort traffic as is. Notice that no change can be seen when observing a link: standard (whole) IP packets encapsulated into Ethernet or PPP frames transit. II. UTC-BASED PIPELINE FORWARDING...