- Email: [email protected]
Small and home networks
Computer Networks 42 (2003) 1–5 www.elsevier.com/locate/comnet
Guest editorial
Small and home networks
In recent years the converging digital technologies of television, publishing, telephony and computers, the ‘‘multimedia revolution’’, combined with access to broadband, has prompted the development of a multitude of high-speed applications in the World Wide Web and the digitization of everyday life. In parallel, there has been a paradigm shift at the network edge. An immediate impact of this evolution is the everincreasing demand for Internet bandwidth, the more intelligent use of already available resources and the use of overlay networks in the home. Cable, DSL and satellite networks bring megabits per second of information and entertainment data to the edge of the home and Small Office Home Office (SOHO). Bridging the last mile, the great motivator of the mid-1990s has been replaced by a new need. The provision of broadband is becoming the distribution of bandwidth and services in the home. The focus is moving from bandwidth to applications. Why? Because the nature of the customer premises has changed. In the past network designers were considering that once the WAN hit the home it would find a single device, more often than not a PC; this was the modem and telephone-line model. Now, homes and SOHOs often contain networks of heterogeneous devices that communicate and share resources. Broadband also enables rich content to be sent to the home as well as integrated multimedia. This combination associated to the means to distribute it in the home creates the incentive for new networking paradigms. Consequently, because of the emergence of the home networks, the nature of networking itself is
changing dramatically. It is moving away from supporting mainly infobusiness applications into the infotainment world where video and audio are now predominant and new applications are developed every day. Home networks? The FCC in the US as well as other governments are recognizing the strategic value of competitive communications driving the current call toward deregulation; in response, Network Service Providers are seeking means of securing their part of the broadband business. In the US broadband connections to homes will grow from 11 million today to over 35 1 million by 2006 creating a multibillion dollar market in the next few years for advanced networking and content distribution gear. Small networks capture this opportunity in a unique way. The Home Local Network (HLN) combines the broadband Internet experience, area networking and entertainment devices. Consequently, the home, the small business or the network on the go (train or planes) can provide services to its connected devices. And in turn those services can be rendered on smaller devices or entertainment gear, not only with PCs or other larger devices. Because of the convergence of multimedia, home controls and traditional communications, the nature of network appliances––especially at the edge––is changing dramatically and creates a need for these devices to adapt to consumer demand. 1
Jupiter Media Matrix 2001.
1389-1286/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S1389-1286(03)00216-0
2
Guest editorial / Computer Networks 42 (2003) 1–5
It is well known that a large percentage of PC sales are now for the second or third multimediaenabled computer: laptops for work and school, home servers, etc. We all carry cell phones that are more and more Internet enabled. Our palmtops can carry wireless networking gear, both WLAN and cellular. Audio and video equipment, even appliances, have Web interfaces and embedded networking capabilities. New gaming systems enable users to play across the Net. But filling our homes and offices with multiple digital means of communications, that generally do not communicate, and our lives with digital files that are scattered and lost across multiple systems will not bring any added value. To increase the value of the digital lifestyle, home networks will foster the development of new protocols for connecting to and managing the digital media we are encountering and using every day. There are already well established standards that have started the evolution from disconnected devices to integrated services. An immediate impact of the growth of home networking is the everincreasing demand for connectivity in all forms and Internet connectivity in particular. In the home environment the all-IP network is emerging as the network layer of choice. Hence, in Internet terms, the home becomes another subnet. This subnet has some specific requirements to accommodate the conflicting requirements of the traffic entering the home. There is the guaranteed high priority traffic, including real-time applications such as high quality video streaming or voice over IP. And, even less QoS critical applications, such as E-mail and Web surfing may end up consuming important resources or requiring guaranteed delivery. Let us look at what seems to be a simple problem: the sharing of devices. Disk space, memory or peripherals like DVD players are more than often tied to one device. The view of the small network as a collaborative entity is still in infancy. Yet the promises are great: use the CPU on a computer when ‘‘in sight’’ instead of a slower palmtop; view DVD movies or training videos on a large television set instead of a small screen; and have content move with the user. This helps use the right device when needed and at the same time
can offer higher quality and leverage the homeÕs capital investment. Home Networks will incorporate the applications that include the well known functions required by the home user, such as MP3 playing, video streaming and Web access, but also provide advanced networking functions based on wireless technology, support for quality of service and resource management and security/privacy functionality. In addition, advance archiving based on Web technology and macro information allows tracking the variety of digital media the end user needs.
Technologies and hardware Over 95% of US homes are passed by cable. With a steady annual growth rate of 32%, digital cable is forecast to nearly overtake analog usage by 2006 accounting for 67% of cable subs by yearend 2006. 2 Add to this the number of ADSL users and the result is that broadband in the home is a reality. All of this offers a solid incentive to intelligently distribute content in the home. The rapid rise of WIFI as a local networking solution, with 11 Mbps and 23+ million units by 2005, shows that wireless is a preferred solution for reaching the end devices. 3 New higher bandwidth standards such as 802.11a and Ultra Wide Band offer high-speed alternatives in the 10s of Mbps with better performance. For example, the 802.11a standard allows the definition of multiple priorities to enable quality of service and allow multimedia services to be guaranteed at several predefined and/or customizable levels of performance. The use of the Bluetooth technologies for personal area networks also makes part of the network offerings in the HLN. While the use of the wireless medium to reach all rendering engines in the end-user network is compelling, other wireline technologies, such as phone lines (HPNA) or powerline also allow connectivity to IP appliances––all with expected rates of several Mbps. 2
MIT Internet Telephony Convergence (ITC) January 2002 Meeting. 3 Forward concepts, 2001.
Guest editorial / Computer Networks 42 (2003) 1–5
Products and standards The current wave of connectivity products for the home, following the PC, is currently targeted at entertainment. Slowly, more advanced networking features are being integrated into broadcast receivers and video software. Advanced set-top box manufacturers are developing cable set-top boxes that combine broadcast and broadband. Some of these set-top boxes may soon use wireless technologies to share capabilities with other devices, following the success of wireless access points and combined DSL/WLAN devices. Other startups have concentrated on flexible software architectures that allow combining TV, Internet access and home controls. Internet-enabled gaming devices are also emerging. Some gaming gear currently offers limited networking capabilities: IEEE1394 connectors for cameras, USB connections to printers and integrated modems for Web page access. These are all interfaces that could make them peers in a network in the future. Finally, true home servers and wireless gateways are starting to emerge too. They offer connectivity, centralized management, archiving capabilities and ubiquitous access. These will also build on the gateway standards being currently pushed by software and computer manufacturers such as the Open Service Gateway Initiative (OSGI) and Universal Plug and Play (UPNP), that enable connectivity amongst heterogeneous devices and software, and the middleware consortiumÕs pushing open platforms for interoperability. It is, however, obvious that while it is an early market; it will take off as the needs become more important. Already, service providers are looking into new services and new revenues from home networks. The opportunity for new HLN technology is huge and now. Only D or is there a place for R too? Phone lines, power lines and wireless LANs have enabled connectivity in small networks. But is there networking beyond connectivity? Home devices, while fully supporting the entertainment and home controls required by the end user,
3
should also provide traditional network management. These include real time functions to support quality of service, resource management and load balancing, security/privacy and also non-real time network management such as provisioning, accounting and fault tolerance. Devices in the home go on and off, hence small networks have an aspect of ad-hocness that cannot be disregarded. While PCs and set-top boxes and IP appliances are more or less fixed, laptop, palmtops and audio players are, if not mobile, at least nomadic. Location-based networking may be necessary and issues of handover between home, community networks and public networks puts requirements on quality of service management in between the different network tiers. There are of course a large number of such protocols available today in the Internet. But then there is the issue of scalability. Usually, scalability means from large to larger, in this case it means from larger to small, maybe really small. The need for small and inexpensive devices in the home dictates the use of networking and software architecture standards for implementing and managing devices, ranging from cell phones and fridges to advanced set-top boxes and multimedia PCs. Some techniques may fail or perform poorly for lack of CPU, memory or power. Some may be inappropriate for reasons of complexity. The use of a state- and connection-less architecture may provide robust support to a broad range of services and the means for the HLN to interconnect to existing infrastructure through open interfaces. The development of lightweight protocols and modular middleware offer some means of overcoming the limitations of end devices. But they are in their infancy and should not be implemented at the expense of networking functionality. A variety of networking technologies can be used in the HLN from wired to wireless. Hence traffic engineering and QoS policy must be defined to ensure that attached devices get their assigned service level. The definition of multiple priority and hierarchical queuing classes as well as novel routing techniques will support future quality of service requirements to allow services to be guaranteed at several predefined and/or customizable levels of performance. There is a need for novel
4
Guest editorial / Computer Networks 42 (2003) 1–5
methods to reduce signaling overhead and session establishment delays while still following open standards and APIs. Recent device discovery mechanisms based on JINI and XML will enable OS- and/or platformindependent tools to implement advanced services and Web-based management tools as well as personalized user interfaces. In addition, open software platforms can enable the gateway to rely on a rich base of new and reliable tools to implement advanced networking functions. Finally, future enhancements of personal gateways, taking cues from advanced cost-based routing based on end to end parameters to interlayer signaling to ad hoc networking and active routing can also lead to interesting research in the field. This special issue This special issue addresses the networking functions of a new generation of Internet/entertainment gateways dedicated to the Home Local Network (HLN). Home networking (and small networks) should allow a network design, and a network management environment, that fosters innovation. The services that the Network Service Providers offer are changing: the Internet, deregulation of communications and advances in ubiquitous computing technology, all are contributing to the changes. It will be a very competitive business and designs will need to adapt. For this reason, we will see that the proposed approaches in this issue favor modular approaches and are more or less independent of the source of the broadband connectivity. At this point, we would like to express our sincere thanks to the authors, reviewers and the Editors-in-Chief for their efforts in putting this issue in place. The first paper, authored by A. Ganz, K. Wongthavarawat and A. Phonphoem proposes a novel software architecture, called Q-Soft, for supporting Quality of Service (QoS) in an HLN. This architecture is implemented in the form of a middleware between the IP and the Network Interface Card (NIC) layers. Using emulation, the authors provide experimental data illustrating the benefits of their architecture when used over wireless and phoneline home networks.
The second paper, by P. Manzoni and J.C. Cano, proposes a new clustering framework, called FRANCA, which aims at minimizing the power consumption of lightweight devices in an HLN. Similarly to the architecture proposed in the first paper, this framework is independent of the underlying mode of communication. FRANCA is expected to be especially useful for providing interoperability between IEEE 802.11 and Bluetooth mobile devices. It used to be that space was the last frontier and Global Area networks were the ultimate dream. On a more human scale, and in an era of realism, it may well turn out that the last frontier is the home. Marie-Jose Montpetit 168 Mystic Valley Parkway Arlington, MA 02474, USA E-mail address: [email protected] David Starobinski 8 St. MaryÕs Street Boston, MA 02215, USA E-mail address: [email protected] Marie-Jose Montpetit holds a Ph.D. in Electrical Engineering from Ecole Polytechnique in Montreal with a focus on coding and communication theory. She has been leading advanced product development in internet over wireless and satellite media for the last 10 years. She is also active in the IETF and the IEEE and had participated in conferences and workshops, as Technical Program Committee Member, Chair, Panelist and Author. Finally she is concerned by the training and continuing education of engineers and has given professional tutorials and courses in the field of satellite networks and wireless systems and directed undergraduate and graduate students. Her research interests cover Internet over heterogeneous media, quality of service, Internet performance and multimedia networking. David Starobinski received his Ph.D. in Electrical Engineering from the Technion, Israel Institute of Technology, in 1999. In 1999–2000, he was a visiting post-doctoral researcher at the EECS Department in the University of California, Berkeley. In 2000, he joined the Electrical and Computer Engineering Department at Boston University, as an Assistant Professor. Dr. Starobinski received a fellowship for prospective researchers from the Swiss National Science Foundation in 1999– 2000, and awards from Intel Corp. in
Guest editorial / Computer Networks 42 (2003) 1–5 1998 and the Gutwirth Foundation in 1996, 1998, and 1999, for outstanding academic achievements. He also received an NSF CAREER award in 2002 for his work on Quality of Service and
5
multiple time-scale traffic. His research interests are in networks performance evaluation, Internet traffic engineering, and highspeed and wireless networking.
Guest editorial
Small and home networks
In recent years the converging digital technologies of television, publishing, telephony and computers, the ‘‘multimedia revolution’’, combined with access to broadband, has prompted the development of a multitude of high-speed applications in the World Wide Web and the digitization of everyday life. In parallel, there has been a paradigm shift at the network edge. An immediate impact of this evolution is the everincreasing demand for Internet bandwidth, the more intelligent use of already available resources and the use of overlay networks in the home. Cable, DSL and satellite networks bring megabits per second of information and entertainment data to the edge of the home and Small Office Home Office (SOHO). Bridging the last mile, the great motivator of the mid-1990s has been replaced by a new need. The provision of broadband is becoming the distribution of bandwidth and services in the home. The focus is moving from bandwidth to applications. Why? Because the nature of the customer premises has changed. In the past network designers were considering that once the WAN hit the home it would find a single device, more often than not a PC; this was the modem and telephone-line model. Now, homes and SOHOs often contain networks of heterogeneous devices that communicate and share resources. Broadband also enables rich content to be sent to the home as well as integrated multimedia. This combination associated to the means to distribute it in the home creates the incentive for new networking paradigms. Consequently, because of the emergence of the home networks, the nature of networking itself is
changing dramatically. It is moving away from supporting mainly infobusiness applications into the infotainment world where video and audio are now predominant and new applications are developed every day. Home networks? The FCC in the US as well as other governments are recognizing the strategic value of competitive communications driving the current call toward deregulation; in response, Network Service Providers are seeking means of securing their part of the broadband business. In the US broadband connections to homes will grow from 11 million today to over 35 1 million by 2006 creating a multibillion dollar market in the next few years for advanced networking and content distribution gear. Small networks capture this opportunity in a unique way. The Home Local Network (HLN) combines the broadband Internet experience, area networking and entertainment devices. Consequently, the home, the small business or the network on the go (train or planes) can provide services to its connected devices. And in turn those services can be rendered on smaller devices or entertainment gear, not only with PCs or other larger devices. Because of the convergence of multimedia, home controls and traditional communications, the nature of network appliances––especially at the edge––is changing dramatically and creates a need for these devices to adapt to consumer demand. 1
Jupiter Media Matrix 2001.
1389-1286/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S1389-1286(03)00216-0
2
Guest editorial / Computer Networks 42 (2003) 1–5
It is well known that a large percentage of PC sales are now for the second or third multimediaenabled computer: laptops for work and school, home servers, etc. We all carry cell phones that are more and more Internet enabled. Our palmtops can carry wireless networking gear, both WLAN and cellular. Audio and video equipment, even appliances, have Web interfaces and embedded networking capabilities. New gaming systems enable users to play across the Net. But filling our homes and offices with multiple digital means of communications, that generally do not communicate, and our lives with digital files that are scattered and lost across multiple systems will not bring any added value. To increase the value of the digital lifestyle, home networks will foster the development of new protocols for connecting to and managing the digital media we are encountering and using every day. There are already well established standards that have started the evolution from disconnected devices to integrated services. An immediate impact of the growth of home networking is the everincreasing demand for connectivity in all forms and Internet connectivity in particular. In the home environment the all-IP network is emerging as the network layer of choice. Hence, in Internet terms, the home becomes another subnet. This subnet has some specific requirements to accommodate the conflicting requirements of the traffic entering the home. There is the guaranteed high priority traffic, including real-time applications such as high quality video streaming or voice over IP. And, even less QoS critical applications, such as E-mail and Web surfing may end up consuming important resources or requiring guaranteed delivery. Let us look at what seems to be a simple problem: the sharing of devices. Disk space, memory or peripherals like DVD players are more than often tied to one device. The view of the small network as a collaborative entity is still in infancy. Yet the promises are great: use the CPU on a computer when ‘‘in sight’’ instead of a slower palmtop; view DVD movies or training videos on a large television set instead of a small screen; and have content move with the user. This helps use the right device when needed and at the same time
can offer higher quality and leverage the homeÕs capital investment. Home Networks will incorporate the applications that include the well known functions required by the home user, such as MP3 playing, video streaming and Web access, but also provide advanced networking functions based on wireless technology, support for quality of service and resource management and security/privacy functionality. In addition, advance archiving based on Web technology and macro information allows tracking the variety of digital media the end user needs.
Technologies and hardware Over 95% of US homes are passed by cable. With a steady annual growth rate of 32%, digital cable is forecast to nearly overtake analog usage by 2006 accounting for 67% of cable subs by yearend 2006. 2 Add to this the number of ADSL users and the result is that broadband in the home is a reality. All of this offers a solid incentive to intelligently distribute content in the home. The rapid rise of WIFI as a local networking solution, with 11 Mbps and 23+ million units by 2005, shows that wireless is a preferred solution for reaching the end devices. 3 New higher bandwidth standards such as 802.11a and Ultra Wide Band offer high-speed alternatives in the 10s of Mbps with better performance. For example, the 802.11a standard allows the definition of multiple priorities to enable quality of service and allow multimedia services to be guaranteed at several predefined and/or customizable levels of performance. The use of the Bluetooth technologies for personal area networks also makes part of the network offerings in the HLN. While the use of the wireless medium to reach all rendering engines in the end-user network is compelling, other wireline technologies, such as phone lines (HPNA) or powerline also allow connectivity to IP appliances––all with expected rates of several Mbps. 2
MIT Internet Telephony Convergence (ITC) January 2002 Meeting. 3 Forward concepts, 2001.
Guest editorial / Computer Networks 42 (2003) 1–5
Products and standards The current wave of connectivity products for the home, following the PC, is currently targeted at entertainment. Slowly, more advanced networking features are being integrated into broadcast receivers and video software. Advanced set-top box manufacturers are developing cable set-top boxes that combine broadcast and broadband. Some of these set-top boxes may soon use wireless technologies to share capabilities with other devices, following the success of wireless access points and combined DSL/WLAN devices. Other startups have concentrated on flexible software architectures that allow combining TV, Internet access and home controls. Internet-enabled gaming devices are also emerging. Some gaming gear currently offers limited networking capabilities: IEEE1394 connectors for cameras, USB connections to printers and integrated modems for Web page access. These are all interfaces that could make them peers in a network in the future. Finally, true home servers and wireless gateways are starting to emerge too. They offer connectivity, centralized management, archiving capabilities and ubiquitous access. These will also build on the gateway standards being currently pushed by software and computer manufacturers such as the Open Service Gateway Initiative (OSGI) and Universal Plug and Play (UPNP), that enable connectivity amongst heterogeneous devices and software, and the middleware consortiumÕs pushing open platforms for interoperability. It is, however, obvious that while it is an early market; it will take off as the needs become more important. Already, service providers are looking into new services and new revenues from home networks. The opportunity for new HLN technology is huge and now. Only D or is there a place for R too? Phone lines, power lines and wireless LANs have enabled connectivity in small networks. But is there networking beyond connectivity? Home devices, while fully supporting the entertainment and home controls required by the end user,
3
should also provide traditional network management. These include real time functions to support quality of service, resource management and load balancing, security/privacy and also non-real time network management such as provisioning, accounting and fault tolerance. Devices in the home go on and off, hence small networks have an aspect of ad-hocness that cannot be disregarded. While PCs and set-top boxes and IP appliances are more or less fixed, laptop, palmtops and audio players are, if not mobile, at least nomadic. Location-based networking may be necessary and issues of handover between home, community networks and public networks puts requirements on quality of service management in between the different network tiers. There are of course a large number of such protocols available today in the Internet. But then there is the issue of scalability. Usually, scalability means from large to larger, in this case it means from larger to small, maybe really small. The need for small and inexpensive devices in the home dictates the use of networking and software architecture standards for implementing and managing devices, ranging from cell phones and fridges to advanced set-top boxes and multimedia PCs. Some techniques may fail or perform poorly for lack of CPU, memory or power. Some may be inappropriate for reasons of complexity. The use of a state- and connection-less architecture may provide robust support to a broad range of services and the means for the HLN to interconnect to existing infrastructure through open interfaces. The development of lightweight protocols and modular middleware offer some means of overcoming the limitations of end devices. But they are in their infancy and should not be implemented at the expense of networking functionality. A variety of networking technologies can be used in the HLN from wired to wireless. Hence traffic engineering and QoS policy must be defined to ensure that attached devices get their assigned service level. The definition of multiple priority and hierarchical queuing classes as well as novel routing techniques will support future quality of service requirements to allow services to be guaranteed at several predefined and/or customizable levels of performance. There is a need for novel
4
Guest editorial / Computer Networks 42 (2003) 1–5
methods to reduce signaling overhead and session establishment delays while still following open standards and APIs. Recent device discovery mechanisms based on JINI and XML will enable OS- and/or platformindependent tools to implement advanced services and Web-based management tools as well as personalized user interfaces. In addition, open software platforms can enable the gateway to rely on a rich base of new and reliable tools to implement advanced networking functions. Finally, future enhancements of personal gateways, taking cues from advanced cost-based routing based on end to end parameters to interlayer signaling to ad hoc networking and active routing can also lead to interesting research in the field. This special issue This special issue addresses the networking functions of a new generation of Internet/entertainment gateways dedicated to the Home Local Network (HLN). Home networking (and small networks) should allow a network design, and a network management environment, that fosters innovation. The services that the Network Service Providers offer are changing: the Internet, deregulation of communications and advances in ubiquitous computing technology, all are contributing to the changes. It will be a very competitive business and designs will need to adapt. For this reason, we will see that the proposed approaches in this issue favor modular approaches and are more or less independent of the source of the broadband connectivity. At this point, we would like to express our sincere thanks to the authors, reviewers and the Editors-in-Chief for their efforts in putting this issue in place. The first paper, authored by A. Ganz, K. Wongthavarawat and A. Phonphoem proposes a novel software architecture, called Q-Soft, for supporting Quality of Service (QoS) in an HLN. This architecture is implemented in the form of a middleware between the IP and the Network Interface Card (NIC) layers. Using emulation, the authors provide experimental data illustrating the benefits of their architecture when used over wireless and phoneline home networks.
The second paper, by P. Manzoni and J.C. Cano, proposes a new clustering framework, called FRANCA, which aims at minimizing the power consumption of lightweight devices in an HLN. Similarly to the architecture proposed in the first paper, this framework is independent of the underlying mode of communication. FRANCA is expected to be especially useful for providing interoperability between IEEE 802.11 and Bluetooth mobile devices. It used to be that space was the last frontier and Global Area networks were the ultimate dream. On a more human scale, and in an era of realism, it may well turn out that the last frontier is the home. Marie-Jose Montpetit 168 Mystic Valley Parkway Arlington, MA 02474, USA E-mail address: [email protected] David Starobinski 8 St. MaryÕs Street Boston, MA 02215, USA E-mail address: [email protected] Marie-Jose Montpetit holds a Ph.D. in Electrical Engineering from Ecole Polytechnique in Montreal with a focus on coding and communication theory. She has been leading advanced product development in internet over wireless and satellite media for the last 10 years. She is also active in the IETF and the IEEE and had participated in conferences and workshops, as Technical Program Committee Member, Chair, Panelist and Author. Finally she is concerned by the training and continuing education of engineers and has given professional tutorials and courses in the field of satellite networks and wireless systems and directed undergraduate and graduate students. Her research interests cover Internet over heterogeneous media, quality of service, Internet performance and multimedia networking. David Starobinski received his Ph.D. in Electrical Engineering from the Technion, Israel Institute of Technology, in 1999. In 1999–2000, he was a visiting post-doctoral researcher at the EECS Department in the University of California, Berkeley. In 2000, he joined the Electrical and Computer Engineering Department at Boston University, as an Assistant Professor. Dr. Starobinski received a fellowship for prospective researchers from the Swiss National Science Foundation in 1999– 2000, and awards from Intel Corp. in
Guest editorial / Computer Networks 42 (2003) 1–5 1998 and the Gutwirth Foundation in 1996, 1998, and 1999, for outstanding academic achievements. He also received an NSF CAREER award in 2002 for his work on Quality of Service and
5
multiple time-scale traffic. His research interests are in networks performance evaluation, Internet traffic engineering, and highspeed and wireless networking.