For any content to be available anywhere, we need a ubiquitous network that will carry this content. As of today, there are two networks, which are ubiquitous. One is the teleconununication network and the other is the Internet network. Both these networks are in real terms network of networks. Different networks have been joined together using a common protocol (glue). In loose terms it can be stated that SSIt7 is the glue for telecouununicarion network whereas TCP/IP is the glue for Internet. We need one of these networks to transport content from One place to another.
We have three types of ba.sic contents: audio, video and text Some of these contents can tolerate little delay in delivery whereas some cannot. Packet switched networks like Internet are better suited for contents which can tolerate little delay. Telecommunication or circuit switch networks are better-suited for realtirne contents that cannot tolerate delays. A ubiq-uitous application needs to use these networks for taking the content from one place to another. A network can be divided into three main segments viz., Core, Edge and Access. Core: As the name signifies; core is the part of the network that is the backbone. This is the innermost part of the network. The primary functions for the core network is to deliver traffic efficiently at the least cost. Core looks at the traffic more from the bit stream point of view. Long-distance operators and backbone operators own core net-works. This part of the network deals with transmission media and transfer points.
Edge: As the name suggests, this is at the edge of the network. These are generally man-aged and owned by ISPs (Internet Service Providers) or local switches and exchanges. Edge looks at the traffic more from the service point of view. It is also responsible for the distribution of the traffic.
Access: This part of the network services the end point or the device by which the serv-ice will be accessed. This deals with the last mile of transmission. This part is either through a wireline or die wireless. From the mobile computing point of view, this will be mostly through the wireless.
Internet is a network of networks and is available universally. In the last few years, the popularity of web-based applications has made more and more sewices available through the Internet. This had a snowball effect encouraging more networks and more contents to be added to the Web. Therefore, Internet is the preferred bearer network for audio, video or text contents that can tolerate delay. Internet supports many protocols. However, for ubiquitous access, web based application is desirable. A web-based appli cation in the Internet uses HTTP protocol and works like a request/response service. This is similar to conventional client/server application. The fundamental difference between a web application and a conventional client/server paradigm is that in the case of conventional client/server application, the user facing client interface contains part of the business logic. However, in the case of web applications, the client will be a thin client without any business logic. The thin client or the agent software in the diem device will relate only to the rendering functions. Such user agents will be a web browser like Mozila, Internet Explorer or Netscape Navigator.
The types of client devices that can access the Internet are rapidly expanding. These client devices are networked either through the wireless or through a wireline. The server on the contrary, is likely to be connected to the access network through wired LAN. In addition to standard computers of different shapes and sizes, client devices can be Personal Digital Assistants (PDA) such as the PaImPilot, Sharp Zaurus, or il'aq; hand-held personal computers such as the EPOC, Symbian, Psion and numerous Windows-CE machines; mobile phones with GPRS/WAP and 3G capability such as Nokia, Sony Ericsson etc; Internet-capable phones such as the Smartphone (cellular) and Screenphone (wired); set-top boxes such as WebTV etc. Even good old voice-based telephone can be used as the client device. Voice-activated Internet browser will be very useful for visually challenged people. To fulfill the promise of universal access to the Internet, devices with very diverse capabilities need to be catered to. For the wireless, the devices range from the small footprint mobile phone to the large footprint laptop comouters.
Edge: As the name suggests, this is at the edge of the network. These are generally man-aged and owned by ISPs (Internet Service Providers) or local switches and exchanges. Edge looks at the traffic more from the service point of view. It is also responsible for the distribution of the traffic.
Access: This part of the network services the end point or the device by which the serv-ice will be accessed. This deals with the last mile of transmission. This part is either through a wireline or die wireless. From the mobile computing point of view, this will be mostly through the wireless.
Internet is a network of networks and is available universally. In the last few years, the popularity of web-based applications has made more and more sewices available through the Internet. This had a snowball effect encouraging more networks and more contents to be added to the Web. Therefore, Internet is the preferred bearer network for audio, video or text contents that can tolerate delay. Internet supports many protocols. However, for ubiquitous access, web based application is desirable. A web-based appli cation in the Internet uses HTTP protocol and works like a request/response service. This is similar to conventional client/server application. The fundamental difference between a web application and a conventional client/server paradigm is that in the case of conventional client/server application, the user facing client interface contains part of the business logic. However, in the case of web applications, the client will be a thin client without any business logic. The thin client or the agent software in the diem device will relate only to the rendering functions. Such user agents will be a web browser like Mozila, Internet Explorer or Netscape Navigator.
The types of client devices that can access the Internet are rapidly expanding. These client devices are networked either through the wireless or through a wireline. The server on the contrary, is likely to be connected to the access network through wired LAN. In addition to standard computers of different shapes and sizes, client devices can be Personal Digital Assistants (PDA) such as the PaImPilot, Sharp Zaurus, or il'aq; hand-held personal computers such as the EPOC, Symbian, Psion and numerous Windows-CE machines; mobile phones with GPRS/WAP and 3G capability such as Nokia, Sony Ericsson etc; Internet-capable phones such as the Smartphone (cellular) and Screenphone (wired); set-top boxes such as WebTV etc. Even good old voice-based telephone can be used as the client device. Voice-activated Internet browser will be very useful for visually challenged people. To fulfill the promise of universal access to the Internet, devices with very diverse capabilities need to be catered to. For the wireless, the devices range from the small footprint mobile phone to the large footprint laptop comouters.
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