Computer Networks Lecture 1: Introduction and Application Layer

Book Overview

• The primary focus of the book 'Computer Networking: A Top Down Approach' is on the Internet and its networks.

Internet Architecture

• The Network Layer is concerned with packet/circuit switching and Internet structure.
• The Internet is described as a network of networks.

Components of the Internet

• The components of the Internet include Access Networks, Network Core, and Network Edges.

Access Networks

• The primary function of access networks is to connect devices to the Internet.

Performance Concerns

• The primary aspect associated with performance concerns such as loss, delay, and throughput is Network Core.

Protocols

• A protocol refers to a set of rules and standards that govern data communication between devices in a network.

Data Transmission

• When one end system has data to send to another end system, it breaks the data into packets and transmits them through the network.
• Packet-switching devices, such as routers, are used for forwarding packets between different networks.

Packet Switching

• A packet switch is a device that forwards packets between different networks.

Communication Links

• The transmission rate of a link is measured in bits per second (bps).
• Physical media that can be used for communication links include Twisted Pair Copper, Coaxial Cable, Fiber Optic Cable, and Radio Waves.
• Coaxial cable transmits data in analog format.

Network Edges

• Examples of network edges include homes, offices, and mobile devices.

Non-Traditional Computing Devices

• Non-traditional computing devices connected to the Internet include smartphones, tablets, and laptops.

Wireless Networks

• WAN stands for Wide Area Network.
• The 802.11 (WiFi) protocol is commonly used in Wireless LANs, offering a typical transmission rate of up to 100 Mbps.
• Wide-area wireless networks, such as cellular networks, use technologies like GSM and offer transmission rates between 1 and 10 Mbps.
• The primary difference in network coverage between Wireless LANs and Wide-area wireless networks is the coverage area.
• Wireless LANs use the 802.11 (WiFi) protocol for data transmission.

Transmission Rates

• The average transmission rate offered by Wide-area wireless networks using 3G, 4G, or 5G technologies is up to 100 Mbps.
• The transmission rate of Category 6 twisted pair copper is up to 1 Gbps.

Physical Media

• Radio waves are a type of physical media that allow signals to propagate freely.
• Fiber optic cable is a type of physical media that transmits data through glass fiber carrying light pulses.
• The primary characteristic of fiber optic cable is that it is resistant to electromagnetic interference.

Circuit Switching

• The primary characteristic of circuit switching is the establishment of a dedicated communication path between two devices before data transmission begins.
• Circuit switching is a method that involves the establishment of a dedicated communication path between two devices before data transmission begins.

Packet Switching

• Packet switching is a method that involves dividing data into smaller units called packets.
• The primary characteristic of packet switching is the transmission of packets through the network without a dedicated communication path.