For Christmas 1994 my family bought a CD-ROM drive for the PC, and some games. The Peter Pan game took 4 months to get working, and the other game defeated the 11 year old who found himself out of lives after 10 minutes. So this Christmas (1995) there were no games and we sought to satisfy our craving for electronic stimuli by looking for Santa on the Web.
To reach Santa from home the rather grand sounding Public Switched Telephone Network (PSTN) is used, which is based on analogue transmission via twisted pair telephone wires and requires the use of modems to transmit data across them. Internet Service Providers make banks of modems available for users, and channel the data into networks to which are attached machines running Internet applications such as Web servers and electronic mail. These networks are shared and usually based on Ethernet technology. The networks are interconnected with a variety of small and large capacity electronic pipes rented from Public Telecommunications Operators. The Internet currently requires data to be split into pieces called packets or segments and fired off into these networks, where given good fortune it will find a route to its destination within a reasonable period of time. Software on computers provides for the administration of this data.
One such piece of software called Trumpet Winsock which was launched, and the modem went ... dee...daa...dee...daa. Then we thought "What can we do? Lets search for something about Christmas. Of course Santa must be on the Net somewhere." Net Search option in Netscape very helpfully produced several references. Off we went happily clicking the mouse in search of Santa on the Web.
Unfortunately this communications technology is by no means seamless or foolproof as was discovered when accessing a promising Santa site called Hotshots of Santa Claus. There were colourful pictures on this site but tears flowed when a grown up picked up the phone to make a voice call, and Trumpet Winsock confused the voice and data, and refused to compete, leading to the pictures freezing. Eventually it was discovered that we were no longer connected to Santa, and the number was re-dialled. Dutifully the longed for pictures were down loaded, taking two to three minutes each. The pictures were even saved them to disk, never to be viewed again!
Some parts of the network were also extremely busy with other Santa Seekers. At Santa's OFFICIAL Home Page on the Web. there were some powerful HO HO HO 's, but the hyperlink to the Disney Pocahontas Colouring page did not respond, probably due to network congestion from Pocahontas fans. This site now appears to be defunct.
Santa's Web sites showed a distinct lack of presentation and content for the target audience. For example at the Santa Claus homepage Santa seemed a little deranged during an interview:
Santa:
"What was it the Romans said when I was younger??? Tempora mutantur et nos mutamur in illis. Sorry. I keep remembering old times - I was quite a latinist but that was 2000 years ago. So the times change and what can we do about it, even if we are a Santa Claus? Nothing, I fear."
A large image of Santas workshop( 40 kbytes) which appeared to offer presents took some time to down load only to find the workshop was full of Electronics and Computer Software! In search of some interactivity a Christmas game Tracking Santa was found. But registration was demanded...and if you forgot, Santa's sled busily travelling round the world was interrupted by a flashing message, urging you not to be so naughty. This was really worrying, maybe Santa would still come to our house, despite our mistake!
The best elements of interactivity came not from Web productions but from posting to the Santa's Web of electronic mail from children, such as the Santa Claus of Greenland Homepage.
Some Aussie children seemed very decisive. Amy and Brett (magna.com.au) said,
"Santa, this is what I want from Christmas: a GameBoy and some games for it, and a Rad Board (but mum and dad won't let me have one). My brother Brett would like a Steel Tec set and a Dr Dreadful Living Lab. Thank you for the presents I got last year and all the other years."
At least we did see a little humour in some other letters .
"Dear Santa, Thank you for replacing my broken doll last year. I didn't mean to pull her head off. Her legs were another accident. Well, her arms, that's another story. Her hair got caught in the scissors, it just wasn't her day! Thank you for understanding, and I will try to be better this year. I promise. Love, Janet and Mom"
The concern in the family was that Santa was using some second rate producers. A Christmas cartoon on TV quickly led to Santa being abandoned in his Web. Obviously there is a problem of real content creation on Santa's Web and the North Pole needs a truly multi-disciplinary team in a new Multimedia Centre. A good marketing manager would have made available information on Santa's activities, some games and a video conference with Santa.
The bottom line communications issue for visitors to the North Pole Web sites is the restricted bandwidth of the shared networks which make up the Internet and low capacity connections to these networks from home or offices. These problems are compounded by the suggestions that the use of multimedia, and video conferencing can reduce wear and tear on sleds. Several solutions are being offered with potential to transmit large quantities of data between networks and provide higher speed access to users so that children at home can to get through to Santa.
Until recently there has been a sharp difference between technologies which connect local area networks (LANs) and wide area networks (WANs) and the speeds obtainable. Local area networks such as Ethernet (10 Mbps bit rate), Token Ring (4 or 16 Mbps), and FDDI (100 Mbps) carried Internet packets. Wide area networks used X.25 or Internet packets carried on links with speeds from 64 kbps to 2 Mbps. The availability of optical fibre to carry data at rates up to several Gigabits per second has opened up fresh possibilities for what is known as broadband communications. The most important of these new technologies are reviewed below. Options such as the Switched Multi-megabit Data Service (SMDS) and Frame Relay simply offer higher speeds, while Asynchronous Transfer Mode (ATM) can work at high speeds and is equally effective in local or wide area networks.
The Switched Multi-megabit Data Service is a broadband data service. SMDS provides a connectionless data service at speeds from 0.5 Mbps to 25 Mbps for connection of LANs. (British Telecom March 1996). It uses variable length packets up to 9188 bytes in length. There are several access classes that limit the sustained data rate and burst data rate that can be injected into the network by a user. These access restrictions may result in discard of packets that exceed a certain limit. The higher speeds of SMDS will be of benefit to multimedia applications seeking to transfer large volumes of data quickly, but the lack of a time structure, for media synchronisation reduces the video conferencing quality obtainable (Minoli and Keinath, 1994).
The commercial high speed packet switched data service is Frame Relay. Frame relay is a connection oriented services operating at n x 64 kbps or 2.048 Mbps. It has evolved from X.25 packet switching and aims to reduce network delays, protocol overheads and equipment cost. Error correction is done on an end to end basis rather than a link to link basis as in X.25 switching. It must be carried over a physical link such as a Kilostream or Megastream link. While useful for connection of LANs, the combination of low throughput, delay variation and frame discard when the link is congested will limit its usefulness to multimedia offerings from Santa. (Minoli and Keinath, 1994)
ATM uses small constant size packets called cells to reduce and control delay. These cells are switched and virtual circuits set up by ATM switches between source and destination. Control of the priorities of packets in ATM switches enables guaranteed delivery of information. ATM can emulate ISDN channels and Ethernet characteristics. ATM is seen as a universal technology which can be used over physical LANs and WANs and may be able to carry both asynchronous and isochronous time structured data. ATM network technology has strong industrial support. ATM can support different speeds, traffic types and quality of service matched to applications. ATM cells coming from a user are delivered at the other end with low loss rate and low delay.
Wide area network interfaces operate at 155.52 Mbps and 622.08 Mbps, both requiring optical fibre interfaces. Local area networks operate at 25 Mbps, 51 Mbps, and 155 Mbps using copper or fibre. Co-ordination of the implementation of ATM is in the hands of the ATM Forum which consists of a wide cross section of companies. The ATM Forum has developed implementor's specifications to try to insure that equipment manufactured by several companies can inter-operate. (Minoli and Keinath, 1994)
ATM users have a dedicated connection to a high speed ATM switch. Several classes of ATM service have been defined. The variable and constant bit rate, connection-orientated with timing services are most appropriate to the transport of real time multimedia. (Minoli and Keinath, 1994) Mechanisms to ensure the real time delivery of audio and resolve management of quality of service levels have still to be agreed. [HREF2]
ATM technology is equally effective in Local and Wide Area Networks. The costs of public ATM provision are not yet known. Provision of ATM services has been restricted to projects like SuperJANET in the UK [HREF1] or the Telstra pilot of a private ATM backbone which will link multimedia centres. (Quantum CMC, 1996). ATM may become a fast highway to Santa, but much work needs to be done on the road to agree the rules, and the toll charges are unknown. (Lynch, 1995)
Children round the world want to contact Santa on the Internet. This at least requires access to analogue telephony services, and preferably digital services able to offer higher speeds than obtainable by modems. Several technologies are emerging which may provide some form of universal digital services.
The most advanced of these is the Integrated Services Digital Network (ISDN) which uses existing copper digital telephone lines from local telephone exchanges up to 4 km away. The standard bit rate available from ISDN is two 64 kbps channels.
Other technologies are being tested by cable TV (Craft, 1995) or Public Telecommunication Operators (PTO's) can deliver higher bit rates using an optical fibre path from the central telecommunications switch is used to a point close enough (a kerbside junction box) to several homes to enable short connections to be made to several homes using cheaper copper twisted pair cables, or coaxial cable.
Mobile radio networks and fixed multiple access systems have to date only been able to deliver low bit rates from 2.4 to 9.6 kbps. (Honkasalo, 1995). However current work is envisages data rates from 64 kbps to 155 Mbps being possible for mobile, fixed multiple access and internal building communications. Much of this work is being undertaken under the umbrella of the ITU task group for Future Public Land Mobile Systems (FPLMTS) which hopes to provide a single radio interface which will remain compatible with wire or optical fibre based systems. (MacFarlane, 1995)
These technical advances together with the demands of rural areas and producers in developing countries to become part of electronic trading networks makes it reasonable to argue that provision of voice services alone are not now enough and at minimum the ITU should redefine the concept of universal access to mean provision of narrow band ISDN. This redefinition would be extremely useful for subscribers in rural Australia, who find it difficult to obtain ISDN from Telstra.
The key issue for all subscribers is the cost of delivering high bit rates to the home, office or factory. The prospects for a world wide internet do not look good. Four billion of the worlds five billion people still lack basic telecommunications facilities. To fund conventional telecommunications projects in developing countries an estimated US$30 billion is needed each year according to the World Bank (Ras-Work, 1995). Existing development institutions have been unable to provide this level of funding. A new institution promoted by the International Telecommunications Union (ITU) called WorldTel believes that good telecommunications assist economic development, and are necessary to attract private investment in the economies of developing countries. WorldTel hopes that private investment can be attracted to large telecommunication projects by guaranteeing a high rate of return on capital and investing in wireless access technologies to reduce the capital investment per subscriber.
In fact no single access technology will provide a low cost solution. A mix of copper, fibre and radio systems are going to be deployed according to local economic considerations. (Cayla, 1995) All these systems will have to interface with the developing narrowband ISDN and broadband ISDN (ATM) and cable operator networks.
ISDN offers point to point delivery, network access, and network interconnection for multimedia. Different data rates from 64 kbps up to 2 Mbps are commercially available which can meet many needs for transporting multimedia. Call set-up times are under one second. Although ISDN is relatively expensive at present, it is likely to continue be cheaper than ATM connections and more widespread in availability for a long time. It is therefore an important tool in bringing multimedia applications to a wide range of users.
The cost of ISDN hardware was high, but is now decreasing. PC cards are available for AUS$400 upwards. Video conferencing cards cost around AUS$6000. [HREF3] Many manufacturers are now beginning to produce products that will use the Point to Point protocol standards, and others are implementing the major European Application Programming Interface (API) called CAPI 2.0 [HREF5]
Both telecommunications and cable TV operators are testing a number of potential technologies which could be used to deliver high bit rates over a few hundred metres of copper cable. The most promising of these is Asymmetric Digital Subscriber Lines (ADSL) and Very High Speed Asymmetric Digital Subscriber Lines (VDSL) which can carry ISDN or ATM as well as video which has been trailed in several countries, including Australia (Shephard, 1995). ADSL technology is aimed at using two wire copper loops at data rates of 6 Mbps (and 25 Mbps using VDSL) in the network to user direction and lower bit rates from the user to network. (Young et al, 1996) This is achieved by using better modulation and coding techniques. The driving force behind this technology is the delivery of on demand compressed VHS quality video to the home by Telecommunication operators wishing to compete with cable TV operators.
ATM at 25 Mbps is already standardised to run over Category 3 copper pairs [HREF4] . There is therefore considerable interest in using ATM over ADSL or from the kerbside to the home (Sharpe, 1995). This data rate is more than sufficient for a single machine, and can provide for video and audio. The problem at present is the cost of putting an ATM switch into a kerbside box.
Another option being proposed as a possible standard (IEEE 802.14 which is not yet public) is some form of cable modem, delivering high speed data, possibly in an Ethernet format. Cable TV companies in the UK are seriously talking of offering Ethernet connections to the home at 10 Mbps. Ethernet uses a contention method to enable workstations attached to the same cable to share the data bandwidth on the cable. Nodes transmit to the network on demand, but continually monitor the network to see if another node is transmitting at the same time. If this occurs both nodes cease transmission, and try again later at random intervals. The throughput with such a system is limited to about half the available bandwidth or 5 to 6 Mbps. Video in MPEG form requires 1 to 2 Mbps per user (Tudor, 1995), so it is clear that only a handful of users can run video applications simultaneously. Audio requires lower bandwidth but is sensitive to unpredictable delays. For instance an intensive file transfer or video stream could prevent an audio application from transmitting for several tens of milliseconds, which is sufficient to reduce the intelligibility of voice. Improved performance is possible if the Ethernet is divided up into segments with only a few attached users. Since Ethernet is a shared medium security issues may arise in sharing segments between homes. Consequently for reasons of performance, quality and security Ethernet is not the best medium to transport last minute Christmas Eve video messages from worried children.
Recent developments in virtual worlds (Whalley, 1996) have highlighted the need networks with sufficient peak bandwidth, reliability, low transit delay, conference management, multicasting and security. Only cell switched data using ATM cell transmission can possibly offer such service guarantees to users and providers on the Internet because media and equipment are shared in a predictable manner.
As ATM is introduced into the public telecommunications backbone Public Telecommunications Operators, (PTO's) can begin to offer sufficient intelligence in their switches to determine if an incoming call is voice, data, video, or some form of conference call while charging accordingly. If it is a data call it can be switched directly to a distant ATM network. ATM is cell switching technology, and can provide such guarantees of a level of service in terms of bit rate, and priority delivery. Effective support for high quality simultaneous video and audio streams is one of the critical capabilities that is being called for to capture the attention of network operators and information providers of interactive broadband services (e.g.., cable television industry and partners). ATM can provide those capabilities and for this reason the Internet community have decided that the next generation Internet (IPng) protocol [HREF7] should be able to work over ATM virtual circuits. (Schulter, 1996)
While some of motivation behind IPng is due to the need to increase the address space available, the opportunity is also being taken to increase the performance of Internet protocols, for multimedia applications. The potential for IPng to provide a universal inter-networking solution is a very attractive possibility, but there are many hurdles to be overcome. For instance, MPEG-2 packetised video might have to be described differently than G.721 PCM packetised voice, although both data streams are real time traffic channels. Hence the network will have to include flexible capabilities for defining these parameters.
ATM will not be available universally for a long time, although international pilot ATM connections are being planned. The only international digital service for many years will be narrow band ISDN. The cost of narrowband ISDN should fall from the current high levels as ATM networks grow because the cost of subscribing to ATM will in part be related to the bandwidth required, so charges should be less for lower bandwidth services such as ISDN.
Direct ISDN based Web calls can provide better performance than Internet routes assuming Telstra and other PTO's install sufficient international ISDN capacity, for which there is every incentive. The technology to do this is here now. Direct calls with 64 kbps or 128 kbps bit rate could be made directly to ISDN equiped Web servers using the Point to Point Protocol (PPP). [HREF6]This protocol incorporates password authentication, which could allow a password to be dynamically allocated on transfer of credit card information. Dynamic allocation of IP addresses (DHCP) is possible but not yet widely used. Java applets are capable of transferring dialling and configuration information to client machines, and assist in setting up calls if such capabilities are not built into client browsers.
The Point to Point Protocol is an example of one small step forward in the networking world, which makes it possible to connect up very different machines anywhere in the World and demonstrates the importance of inter-operablity.
ISDN as conceived 20 years ago was meant to provide a universal interface for data, voice, video, faxes etc. It is obviously not going to achieve this aim, since technology has moved so fast. ATM is the latest candidate for the universal interface. This begs the question. Is it worth trying to create standards for universal services and interfaces. The answer is that if simple, inter-operable technology is politically and economically advantageous then the creation of standards and common interfaces is necessary task.(Taylor, 1995)
Inter-operability is possible. Dual mode ATM and 10 Mbps Ethernet cards are now available. A World Wide Web hyper-link can make a video or audio call on ISDN or ATM which in real time. Data and video inter-operablity between ISDN and ATM is now available [HREF11]. The glue which will make this possible is a multimedia programming architecture.
By having this common underlying infrastructure, users could select their desired/required application services based on their unique needs, with assurance that the intermediate networking service will support their communication requirements. [HREF8] Designers of a common multimedia architecture face three problems :-
Achieving inter-operability and resource sharing is difficult. For example, sharing bandwidth on a link may not work effectively if one protocol suite backs off in its demands and the other does not. Inter-operability and resource sharing both require co-operation between the various developers and users. In fact the Multimedia Communications Forum (MMCF) [HREF9] are developing a reference model for multimedia architecture to allow easy application development for independent software producers. The first result of this work will be Transport Services Interface which will be a type of multimedia WinSocket specification, able to negotiate bandwidth, delay, priority and other quality of service parameters required by multimedia.
The MMCF have developed the concept of Middleware to provide multimedia interfaces to the application and transport levels via application programming interfaces (API's). Ideally there should only be one API for an ISDN or ATM user cards. In practice ISDN cards have several API's [HREF5] and the status of an API for ATM cards is unclear.
Cochrane (1996) has called for systems to be engineered as a whole, rather than as disconnected hardware, networks, and applications. This paper argues that public digital service provision should be engineered so that plugging in an ISDN or ATM card into the public network was as easy, or easier than plugging in an Ethernet card into a PC and LAN. Then both customers and providers would be able to use Web or Internet services connected to both public and private networks as easily as the telephone is used today to access a weather forecast.
If a Web Browser incorporated real-time multimedia technology and was able to select different networks or levels of service, tremendous possibilities open up. We are used to having to put up with painfully slow delivery of large data files, video and audio files (Can U See Me with difficulty, Real Audio with a sore throat). Users browsing the Web, could click on a hyperlink to:
ISDN can deliver data faster than many parts of the network during busy periods. Bottlenecks in the Internet could be totally bypassed. [HREF10] If files were large for ISDN speeds e.g.. a distance learning package, a student could 'order' its delivery by an ISDN return call at a later time.
Some PTO's may be beginning to appreciate that seamless access to a switched Internet would render the role of the specialised Internet provider obsolete. Of course present day Internet access service providers could construct a similar service. They do have the disadvantage of having to rent bandwidth from the public telecommunications operators, who could undercut their offerings. The provision of Internet service is already undergoing an industry shakeout in the UK. It is likely that the current Internet service providers will become allied with PTO's or move towards publishers and media corporates so that they can concentrate more on the provision of content than access.
Ritchie (1996) envisages that:
Yet use of the World Wide Web running over the existing Internet would currently be a risky business proposition given a number of major deficiencies in the technology. Market size is small since does not have a truly world wide coverage, because the availability of Internet nodes and telecommunications facilities is very uneven. Response and access times are poor. Facilities that can be offered are limited due to inter-operability or compatibility problems. Reliable methods for generation of revenue are not yet widely implemented.
This situation could not be tolerated by a publishing company using paper media. The problem for publishers on the Web is the current structure of the Internet, as a shared network with un-predictable performance, provides no incentive to provide a better, faster service to users. But if users were charged extra, for additional or faster service, good or useful content, information, products and services and these features were readily deliverable to specific groups of users then an incentive would exist to make investments and develop services.
Some academic networks could apparently remain free at the point of use, although experience shows that such networks never allow for sufficient capacity to meet demand. The provision of popular useful services and academic courses will require the provision of additional network bandwidth or switched ISDN/ATM circuits. Reports indicate that Telstra will spend AUS$15 million to upgrade the US connection to 34 Mbps, with a 100 Mbps connection anticipated at a cost of AUS$75 million (The Australian, 1996). It seems unlikely that Telstra will cover these costs from new telephone subscribers using the Internet, and call charges, so a more direct charging mechanism for Internet use is needed to fund higher levels of international capacity.
When the network can guarantee access and performance, new opportunities will open up for information providers, who will sell their information directly or via a new copyright process (Nelson, 1994). Hopefully this will result in a higher quality of information since publishers will be able to recover their costs. We will be able to dial directly via ISDN, the local campus cable TV or ATM network, over guaranteed physical or virtual circuits which we will pay for by the session or by contractual arrangements. We will look at Santa's toy database, talk to him in a video call, and enjoy whatever delights can be transmitted down the line. Santa may have to consider an alliance with a publishing or media tycoon to build his web site, but hopefully he will make it worth missing the cartoons on TV!
The Australian, (1996), Tuesday, January 23rd, p32.
British Telecom (1996) Information Exchange, March 1996, p14-15.
D. Cartwright (1996) Waiting to catch the right wave, Network Week , 24th January 1996, p27-32. R. Sharpe and H. Lalani, (1995) Taking ATM Home, Telecommunications,December 1995, p30-36.
G. Cayla, (1995) Wireless Local Loop: At last, the last mile, 7th World Telecommunication Forum, Technology Summit, Vol2, International Telecommunications Union, Geneva, October, 1995, p331-335.
P. Cochrane, (1996) I see and I remember, 3D and Multimedia on the Internet, WWW and Networks, International Conference, National Museum of Photography, Film and Television, Bradford, April 1996.
K. Craft, (1995) Integrated Cable Telephony Solutions, 7th World Telecommunication Forum, Technology Summit, Vol1, International Telecommunications Union, Geneva, October, 1995, p657-662.
H. Honkasalo, (1995) The Technical Evolution of GSM, 7th World Telecommunication Forum, Technology Summit, Vol2, International Telecommunications Union, Geneva, October, 1995, p15-19.
D. Lynch and J Jowett, (1995) ATM - From Curse to Profit, Telecommunications, July 1995, p80-81.
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D. Minoli and R. Keinath (1994) Distributed Multimedia Through Broadband Communications, 1994, p150-175, Artech House, Norwood, USA.
T.H. Nelson (1994) Publishing in the Point and Click Universe, National Covergence Symposium, Sydney, Australia, April 1994
Quantum (1996) CMC, Brisbane, QLD, Proposal Documents.
T. Ras-Work (1995) The WorldTel Concept in International Telecommunication Union, Celebrating 130 years 1865-1995, p454-457 published by International Systems and Communications, London, UK.
I. Ritchie, (1996) Commercial Publishing on the Internet, 3D and Multimedia on the Internet, WWW and Networks, International Conference, National Museum of Photography, Film and Television, Bradford, April 1996.
P. Schulter (1996) A Framework for IPv6 Over ATM Draft Request for Comment held as file draft-schulter-ipv6atm-framework-01.txt, .ps in local mirrors of RFC documents.
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A. Taylor (1995) The Reality of ISDN for Small Business, 7th World Telecommunication Forum, Technology Summit, Vol1, International Telecommunications Union, Geneva, October, 1995, p203-207.
P.N.Tudor, (1995) MPEG-2 Video Compression, 1995, Electronics and Communication, Volume 7 Number 6, December 1995, p257-264
S. Whalley, (1996) Using Virtual Worlds over Public Networks, 3D and Multimedia on the Internet, WWW and Networks, International Conference, National Museum of Photography, Film and Television, Bradford, April 1996.
G. Young, K.T. Foster and J.W. Cook (1996) Broadband multimedia delivery over copper, 1996, Electronics and Communication, Volume 8 Number 1, February 1996, p25-36
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