David Banks

A high-performance network architecture for a PA-RISC workstation

With current low-cost high-performance workstations, application-to-application throughput is limited more by host memory bandwidth than by the cost of protocol processing. Conventional network architectures are inefficient in their use of this memory bandwidth, because data is copied several times between the application and the network. As network speeds increase further, network architectures must be developed that reduce the demands on host memory bandwidth. The authors discuss the design of a single-copy network architecture, where data is copied directly between the application buffer and the network interface. Protocol processing is performed by the host, and transport layer buffering is provided on the network interface. They describe a prototype implementation for the HP Apollo Series 700 workstation family that consists of an FDDI network interface and a modified 4.3BSD TCP/IP protocol stack, and report some early results that demonstrate twice the throughput of a conventional network architecture and significantly lower latency. >

User-space protocols deliver high performance to applications on a low-cost Gb/s LAN

Two important questions in high-speed networking are firstly, how to provide Gbit/s networking at low cost and secondly, how to provide a flexible low-level network interface so that applications can control their data from the instant it arrives. We describe some work that addresses both of these questions. The Jetstream Gbit/s LAN is an experimental, low-cost network interface that provides the services required by delay-sensitive traffic as well as meeting the performance needs of current applications. Jetstream is a combination of traditional shared-medium LAN technology and more recent ATM cell- and switch-based technology. Jetstream frames contain a channel identifier so that the network driver can immediately associate an incoming frame with its application. We have developed such a driver that enables applications to control how their data should be managed without the need to first move the data into the applications address space. Consequently, applications can elect to read just a part of a frame and then instruct the driver to move the remainder directly to its destination. Individual channels can elect to receive frames that have failed their CRC, while applications can specify frame-drop policies on a per-channel basis. Measured results show that both kernel- and user-space protocols can achieve very good throughput: applications using both TCP and our own reliable byte-stream protocol have demonstrated throughputs in excess of 200 Mbit/s. The benefits of running protocols in user-space are well known- the drawback has often been a severe penalty in the performance achieved. In this paper we show that it is possible to have the best of both worlds.

Afterburner (network-independent card for protocols)

Many current implementations of protocols such as the Transmission Control Protocol/Internet Protocol (TCP/IP) are inefficient because data are often accessed more frequently than necessary. Three techniques that reduce the need for memory bandwidth are proposed. The techniques are copy-on-write, page remapping, and single-copy. Afterburner, a network-independent card that provides the services that are necessary for a single-copy protocol stack, is described. The card has 1 MByte of local buffers and provides a simple interface to a variety of network link adapters, including HIPPI and asynchronous transfer mode (ATM). Afterburner can support transfers to and from the link adapter card at rates up to 1 Gbit/s. An implementation of TCP/IP that uses the features provided by Afterburner to reduce the movement of data to a single copy is discussed. Measurements of the end-to-end performance of Afterburner and the single-copy implementation of TCP/IP are presented.<<ETX>>

Content-Centered Collaboration Spaces in the Cloud

Emphasizing communication, collaborative work, and community, the authors envision a cloud-based platform that inverts the traditional application-content relationship by placing content rather than applications at the center, enabling users to rapidly build customized solutions around their content items. The future of collaboration will focus on building and sustaining communities around content, tasks, and ideas. Hosted entities known as content spaces will support ecosystems of users and developers around this content. To make their case, the authors review the dominant trends in computing that motivate the exploration of new approaches for content-centered collaboration and discuss ways to address certain core problems for users and organizations.

Breaking open the set top box

In this paper we describe the work being done at HP Labs Bristol in the area of home networks and gateways. This work is based on the idea of breaking open the set top box by physically separating the access network specific functions from the application specific functions. The access network specific functions reside in an access network gateway that can be shared by many end user devices. The first section of the paper present the philosophy behind this approach. The end user devices and the access network gateways must be interconnected by a high bandwidth network which can offer a bounded delay service for delay sensitive traffic. We are advocating the use of IEEE 1394 for this network, and the next section of the paper gives a brief introduction to this technology. We then describe a prototype digital video broadcasting satellite compliant gateway that we have built. This gateway could be used, for example, by a PC for receiving a data service or by a digital TV for receiving an MPEG-2 video service. A control architecture is the presented which uses a PC application to provide a web based user interface to the system. Finally, we provide details of our work on extending the reach of IEEE 1394 and its standardization status.

AAL5 at a Gigabit for a Kilobuck

We present a novel LAN that has been designed to meet three criteria: it should be low cost, support standard protocols, and provide high performance. The LAN interconnects many workstations in a ring topology with a link rate of 1 Gbit/s. The packet format is the same as that of a B-ISDN cell except that our packets can have arbitrary length. The network also provides hardware support for ATM Adaptation Layer 5 as weIl as TCP/IP.We have implemented the ring network and we describe a network interface card which provides hardware support for critical functions such as calculating checksums. This card is used in conjunction with a second card that supports a single-copy implementation of the TCP/IP protocols. The application-to-application throughput has been measured at rates in excess of 200 Mbit/s between two workstations.