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Data networks are telecommunications networks installed and operated for information exchange between data communication devices such as computers. Because of the dramatic changes that have occurred to Data Networks, such as high-speed data and evolving Ethernet technology, almost all professionals in the datacom and telephone industries have been impacted. These new data networking products and services that are being introduced into the marketplace have advanced features and services that will enhance or replace ineffective or outdated systems. This excerpted chapter from Telecom Made Simple explains many fundamentals of data networks, including: Local area networks (LAN), the Internet, data terminals, network access control, protocols, other types of networks, networking devices, data communications systems, phoneline networking, and data network services. Low speed and high-speed data networks are also explained along with upcoming enhancements.
Sample Diagrams
There are 17 self explanatory diagrams in this book
Data Router Operation
This figure shows a how a router can dynamically forward packets toward their destination. This diagram shows that a router contains a routing table (database) that dynamically changes. This diagram shows a router with address 100 is connected to two other routers with addresses 800 and 900. Each of these routers periodically exchanges information allowing them to build routing tables that allow them to forward packets they receive. This diagram shows that when router 100 receives a packet for a device number 952, it will forward the packet to router 900. Router 900 will then receive that packet and forward it on to another router that will help that packet reach its destination.
Internet Data Routing
This figure shows that the Internet is the network of networks and it communicates using the universal protocol language TCP/IP. This diagram shows a user who is sending email through the Internet. In this diagram, the application is email. The data from the email is divided into packets and given sequence number by TCP protocol. The destination address is appended to each packet by the IP layer. The IP packets are then sent through an Ethernet LAN by encapsulating the IP datagram within the Ethernet data packet. When the data packet is extracted from the Ethernet, it is placed on the E1 transmission line. When the IP data packet reaches the ATM network, it is subdivided into very small 53 byte data packets that travel through the ATM network. When the ATM packets reach their destination in the ATM network, the original IP datagram is recreated and transferred via the T1 communication line. The T1 communication line interfaces to another Ethernet data network. This Ethernet data network encapsulates the IP datagram and forwards it on to the NIC of the receiving computer. The NIC of the receiving computer removes the IP address and reassembles the IP data packets to form the original email message.
Table of Contents
Data Networks
- Data Terminals
- Network Interface Card (NIC)
- LAN Wiring
- Network Distribution and Routing
- Network Access Control
- Protocols
- Network Management
Overview
- Premises Distribution Networks (PDN)
- Local Area Networks (LANs)
- Metropolitan Area Networks (MAN's)
- Wide Area Networks (WAN's)
- Wireless Data Networks
Technologies
- Data Modems
- Digital Service Unit (DSU)/Channel Service Unit (CSU)
- Hub
- Bridge
- Routers
- Gateways
- Firewall
Data Communications Systems
- Ethernet
- Token Ring
- Fiber Distributed Data Interface (FDDI)
- Internet
- Asynchronous Transfer Mode 25 (ATM 25)
- Phoneline Networking
- Universal Serial Bus (USB)
- FireWire
Services
- Internet Service Provider (ISP)
- Virtual Private Networks (VPN's)
Future Enhancements
- 10 Gigabit Ethernet (10 GE)
- LAN Telephony
- Storage Area Networks (SANs)
About the Author
Mr. Lawrence Harte is the president of Althos, an expert information provider covering the communications industry. He has over 29 years of technology analysis, development, implementation, and business management experience. Mr. Harte has worked for leading companies including Ericsson/General Electric, Audiovox/Toshiba and Westinghouse and consulted for hundreds of other companies. Mr. Harte continually researches, analyzes, and tests new communication technologies, applications, and services. He has authored over 30 books on telecommunications technologies on topics including Wireless Mobile, Data Communications, VoIP, Broadband, Prepaid Services, and Communications Billing. Mr. Harte’s holds many degrees and certificates include an Executive MBA from Wake Forest University (1995) and a BSET from the University of the State of New York, (1990). Mr. Harte can be contacted at LHarte@Althos.com.
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