Select the “Edit” tab to edit an article or select the “Leave a Comment” tab to submit questions or comments about the article. This article provides wan technologies cisco pdf for understanding internetworking technology.
Different components of internetwork and the protocols used are described. Cisco IOS documentation on www. An internetwork is a collection of individual networks, connected by intermediate networking devices, that functions as a single large network. Internetworking refers to the industry, products, and procedures that meet the challenge of creating and administering internetworks.
A LAN is a high-speed data network that covers a relatively small geographic area. LANs offer computer users many advantages, including shared access to devices and applications, file exchange between connected users, and communication between users via electronic mail and other applications. A WAN is a data communications network that covers a relatively broad geographic area and that often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.
This article provides a broad introduction to specifications that comprise the Internet protocols. Discussions include IP addressing and key upper-layer protocols used in the Internet. Specific routing protocols are addressed individually later in this document. Bridges and switches are data communication devices that operate principally at Layer 2 of the OSI reference model. As such, they are widely referred to as data link layer devices. Several kinds of bridging have proven important as internetworking devices. Transparent bridging is found primarily in Ethernet environments, while source-route bridging occurs primarily in Token Ring environments.
Today, switching technology has emerged as the evolutionary heir to bridging-based internetworking solutions. Switching implementations now dominate applications in which bridging technologies were implemented in prior network designs. Superior throughput performance, higher port density, lower per-port cost, and greater flexibility have contributed to the emergence of switches as replacement technology for bridges and as complements to routing technology. Routing is the act of moving information across an internetwork from a source to a destination. Along the way, at least one intermediate node typically is encountered. This distinction provides routing and bridging with different information to use in the process of moving information from source to destination, so the two functions accomplish their tasks in different ways.
Network management means different things to different people. In some cases, it involves a solitary network consultant monitoring network activity with an outdated protocol analyzer. In other cases, network management involves a distributed database, auto polling of network devices, and high-end workstations generating real-time graphical views of network topology changes and traffic. In general, network management is a service that employs a variety of tools, applications, and devices to assist human network managers in monitoring and maintaining networks. Service providers are attracted by the lower-cost model-the cost of packet voice is currently estimated to be only 20 to 50 percent of the cost of a traditional circuit-based voice network. Likewise, enterprise network designers are interested in direct cost savings associated with toll-bypass and tandem switching.
Both are also interested in so-called “soft savings” associated with reduced maintenance costs and more efficient network control and management. Finally, packet-based voice systems offer access to newly enhanced services such as Unified Messaging and application control. These, in turn, promise to increase the productivity of users and differentiate services. Integration of voice and data technologies has accelerated rapidly in recent years because of both supply- and demand-side interactions. On the demand side, customers are leveraging investment in network infrastructure to take advantage of integrated applications such as voice applications. On the supply side, vendors have been able to take advantage of breakthroughs in many areas, including standards, technology, and network performance. Wireless communication is the transfer of information over a distance without the use of electrical conductors or “wires”.
When the context is clear, the term is often shortened to “wireless”. Wireless communication is generally considered to be a branch of telecommunications. Other examples of wireless technology include GPS units, garage door openers and or garage doors, wireless computer mice, keyboards and headsets, satellite television and cordless telephones. Historically, CATV has been a unidirectional medium designed to carry broadcast analog video channels to the maximum number of customers at the lowest possible cost. CATV was introduced in the 1940s and 1950s and for many decades little changed beyond increasing the number of channels supported.
The technology to provide high-margin, two-way services remained elusive to the operator. The 2000s and the rise of IPTV saw this delivery model change. Today CATV providers utilize IP protocols for two-way data traffic while simultaneously delivering interactive video programing. The AS3600, AS5200, AS5300, and AS5800 are all examples of routers that have the capability to run a PRI along with banks of digital modems. The AS2511, on the other hand, is an example of a router that communicates with external modems. Since the time of Internetworking Technologies Handbook, 2nd edition, the carrier market has continued to grow, and there have been demands for higher modem densities.