Dan Decasper

Router plugins: a software architecture for next generation routers

Present day routers typically employ monolithic operating systems which are not easily upgradable and extensible. With the rapid rate of protocol development it is becoming increasingly important to dynamically upgrade router software in an incremental fashion. We have designed and implemented a high performance, modular, extended integrated services router software architecture in the NetBSD operating system kernel. This architecture allows code modules, called plugins, to be dynamically added and configured at run time. One of the novel features of our design is the ability to bind different plugins to individual flows; this allows for distinct plugin implementations to seamlessly coexist in the same runtime environment. High performance is achieved through a carefully designed modular architecture; an innovative packet classification algorithm that is both powerful and highly efficient; and by caching that exploits the flow-like characteristics of Internet traffic. Compared to a monolithic best-effort kernel, our implementation requires an average increase in packet processing overhead of only 8%, or 500 cycles/2.1ms per packet when running on a P6/233.

A scalable high-performance active network node

Active networking in environments built to support link rates up to several gigabits per second poses many challenges. One such challenge is that the memory bandwidth and individual processing power of the routers microprocessors limit the total available processing power of a router. In this article we identify and describe three components, which promise a high-performance active network solution. This implements the key features typical to active networking, such as automatic protocol deployment and application specific processing, and it is suitable for a gigabit environment. First, we describe the hardware of the active network node (ANN), a scalable high-performance platform based on off-the-shelf CPUs connected to a gigabit ATM switch backplane. Second, we introduce the ANNs modular, extensible, and highly efficient operating system (NodeOS). Third, we describe an execution environment running on top of the NodeOS, which implements a novel large-scale active networking architecture called distributed code caching.

An active router architecture for multicast video distribution

Video distribution over the Internet poses many challenges. Due to the best-effort nature of todays public data networks, end system applications cannot rely on either bandwidth or delay guarantees. We designed and implemented a prototype of a multicast video distribution architecture involving knowledgeable active routers, a scalable video codec based on the wavelet transformation, and a high-performance video scaling algorithm implemented as a router plug-in. The plug-in scales the video with an average overhead of only 22 /spl mu/s per video datagram and is installed on-the-fly on the routers after the sender starts transmitting video for the first time. Through experiments on our test network, we show that we can dramatically improve the video quality on the receivers (up to 15 dB PSNR) by scaling the video on the routers to almost any target bandwidth. The target bandwidth is evaluated by the router solely based on monitoring of the load situation of the routers downstream links and can be adjusted within 50 ms.

Router Plugins: A Modular and Extensible Software Framework for Modern High Performance Integrated Services Routers

Present day routers typically employ monolithic operating systems which are not easily upgraded and extensible. WIth the rapid rate of protocol development it is becoming increasingly important to dynamically upgrade router software in an incremental fashion. We have designed and implemented a high performance, modular, extended integrated services router software architecture in the NetBSD operating system kernel. This architecture allows code modules, called plugins, to be dynamically added and configured at run time. One of the novel features of our design is the ability to bind different plugins to individual flows; this allows for distinct plugin implementations to seamlessly... Read complete abstract on page 2.

Crossbow: a toolkit for integrated services over cell switched IPv6

The project Crossbow provides a framework to investigate services and mechanisms including resource management and packet scheduling for multimedia/multicast applications. In particular the Internet Protocol version 6 (IPv6, IP next generation, IPng) protocol suite on top of ATM is considered to demonstrate possible synergy between ATM and IPv6. The presented architecture includes IPv6 and RSVP running on BSD Unix using the 1.2 Gbps APIC (ATM port interconnect controller) chip, as well as support for Ethernet networks.

Tags for high performance active networks

We propose the use of selectors for (active) packet flows similar to tags employed in the IP world. Their impact on the performance of an active network node is significant, as active packets have to be demultiplexed not only to the network layer, but all the way to an application level execution environment. We have built an Active Network Node that implements the selector based Simple Active Packet Format (SAPF). Our measurements show that SAPF packets can be processed 30% faster than regular IP packets that use the traditional Active Network Encapsulation Protocol (ANEP) header.