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Questions and Answers
What is a characteristic feature of Asynchronous Transfer Mode (ATM) compared to Ethernet or the internet?
What is a characteristic feature of Asynchronous Transfer Mode (ATM) compared to Ethernet or the internet?
Which type of ATM service guarantees a minimum capacity but allows for bursts of higher capacities when traffic is low?
Which type of ATM service guarantees a minimum capacity but allows for bursts of higher capacities when traffic is low?
Which of the following is NOT a use case that ATM was designed to handle effectively?
Which of the following is NOT a use case that ATM was designed to handle effectively?
What challenge did ATM designers face when developing the network?
What challenge did ATM designers face when developing the network?
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What year saw the launch of the new Wi-Fi standard 802.11ac, which offered significantly faster speeds?
What year saw the launch of the new Wi-Fi standard 802.11ac, which offered significantly faster speeds?
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Which of the following components is NOT typically part of a Large Scale Network?
Which of the following components is NOT typically part of a Large Scale Network?
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What distinguishes a Wide Area Network (WAN) from a Local Area Network (LAN)?
What distinguishes a Wide Area Network (WAN) from a Local Area Network (LAN)?
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What significant advancement in the history of WAN occurred in 1964?
What significant advancement in the history of WAN occurred in 1964?
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Which protocol is most commonly used for communication over WANs?
Which protocol is most commonly used for communication over WANs?
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Which concept is used to describe WANs in a similar way to a banking system?
Which concept is used to describe WANs in a similar way to a banking system?
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Study Notes
Large Scale Networks / Wide Area Networks
- Large scale networks (LSN) or Wide Area Networks (WAN) are computer networks that connect computers over a distance greater than 100km.
- WANs connect multiple Local Area Networks.
- They are typically deployed on a larger scale than a LAN.
- WANs are similar to a banking system where multiple branches in different cities are connected to share data.
- The TCP/IP (Transmission Control Protocol/Internet Protocol) is typically used for WANs in coordination with routers, switches, firewalls, and modems.
Components of a WAN
- Hosts
- Clients
- Bridges
- Servers
- Routers
- Links of various media
- Applications
- Protocols
- Hardware, software
Brief History of WANs
- 1940: George Stibitz invented the teletype.
- 1964: IBM implemented SABRE, a reservation system and online transaction processing system.
- 1980s: ARPANET (Advanced Research Projects Agency Network) was the first wide-area packet-switched network.
- Access to the ARPANET was expanded in 1981.
- The Internet Protocol Suite (TCP/IP) was introduced in 1982.
- 2000s: ADSL (Asymmetric Digital Subscriber Line) was launched in the UK.
- 2011: Fiber-optic broadband and new DOCSIS standards allowed broadband speeds of 100 Mbps.
- 2014: The Wi-Fi standard 802.11ac launched, offering speeds of over 2 Gbps and better signal coverage.
Standards for WANs
- ATM (Asynchronous Transfer Mode)
- Dial-up Internet
- DSL (Digital Subscriber Line)
- ISDN (Integrated Services Digital Network)
- SONET
- SD-WAN (Software Defined-WAN)
- Cellular technologies
ATM (Asynchronous Transfer Mode)
- A switching technique used in telecommunication networks that utilizes asynchronous time-division multiplexing.
- Data is encoded into small, fixed-sized cells for efficient transmission.
ATM Types
- ABR (Available Bit Rate): Guaranteed minimum capacity with bursts to higher capacities during low traffic periods.
- CBR (Constant Bit Rate): Fixed bit rate, similar to a leased line.
- UBR (Unspecified Bit Rate): No guaranteed throughput, suitable for applications tolerant of delays.
- VBR (Variable Bit Rate): Specified throughput with uneven data transmission, making it ideal for voice and video conferencing.
Development of ATM
- ATM designers had to meet diverse requirements of voice, video, and data.
- Voice and video require low delay and jitter for smooth delivery.
- Video requires a higher data rate than audio.
- Data networks often introduce jitter.
ATM Cell Structure
- 53 Octets (Bytes): 5 octets for the header and 48 octets for data.
- Header Information: Flow Control, VPI (Virtual Path Identifier), VCI (Virtual Channel Identifier), Payload Type, PRIO (Priority), Cyclic Redundancy Check.
ATM Advantages
- Supports fixed-length cells of 53 bytes.
- Virtual data circuits ranging from 45 Mbps to 622 Mbps.
- Low system overhead and straightforward implementation.
- No limitations on the frequency or timing of data packet transfer.
ATM Disadvantages
- Not widely accepted.
- Expensive, complex, and lacks interoperability with other technologies.
Dial-up Internet
- Access to the Internet through a public switched telephone network (PSTN).
- Uses a modem to encode data into audio frequency signals.
Dial-up Internet Architecture
- Modem
- PSTN (Public Switched Telephone Network)
- ISP (Internet Service Provider)
Dial-up Internet Speeds
- Measured in Baud (bits per second).
Disadvantages of Dial-up Internet
- Slow speeds (up to 56 kbps).
- Landline is tied up during use.
DSL (Digital Subscriber Line)
- Allows for high-speed internet access over telephone lines.
- Typically referred to as DSL broadband.
DSL Network Architecture
- DSL modem
- Telephone line
- DSLAM (Digital Subscriber Line Access Multiplexer)
ISDN (Integrated Services Digital Network)
- A set of communication standards for digital transmission of voice, video, data.
- Uses existing circuits of the PSTN (Public Switched Telephone Network).
ISDN Services
- Digitized voice services, multimedia quality exchange, enhanced digital services, entertainment services (TV, VOD).
ISDN Network Architecture
- ISDN terminal adapter (TA)
- ISDN network
- PSTN
ISDN Bit Rates
- Vary depending on the application.
DSL Advantages
- Faster data transmission than ISDN.
- Continuously connected; no dialling required.
- Higher frequencies provide faster speeds compared to dial-up.
SONET / SDH (Synchronous Optical Networking / Synchronous Digital Hierarchy)
- Standardized protocols for transferring digital bit streams over optical fiber.
- Employs lasers or LEDs to transmit data.
- SONET is the US standard, while SDH is used internationally.
SONET Network Architecture
- Optical carrier (OC)
- Digital signal (DS-n)
- Optical fiber network
Advantages of SONET / SDH
- Backbone of modern carrier networks.
- Supports high-speed transmission (up to 10 Gbps).
- Multiplexing and synchronization methods are standardized.
SD-WAN (Software Define-WAN)
- An application of SDN (Software Defined Networking) for WAN connections.
- Connects enterprise networks across large geographic distances.
SD-WAN Network Architecture
- SD-WAN controllers
- SD-WAN routers
- WAN connections
- MPLS (Multiprotocol Label Switching)
SD-WAN Advantages
- Combines bandwidth from multiple WAN connections.
- Easier WAN connection management (add/remove).
- Cost-effective compared to carrier-grade MPLS.
- Enhanced security through encryption and network segmentation.
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Description
Explore the fundamentals of Large Scale Networks (LSN) and Wide Area Networks (WAN) with this quiz. Learn about their components, history, and operation principles, including the role of TCP/IP. Test your knowledge on how WANs connect multiple local networks and their significance in communication systems.
