Computer Networks: TCP/IP Layers and OSI Model

• Course code is 30102414
• Credit hours are 3
• The instructor is Dr. Ahmad A.M Sharadqh
• Instructor's contact email addresses are [email protected] and [email protected]
• Office hours are on Mondays and Wednesdays from 11:00 AM to 12:00 PM
• Class times are Sundays, Tuesdays, and Thursdays from 11:00 AM to 12:00 PM, and Mondays and Wednesdays from 9:30 AM to 11:00 AM
• Classes take place online
• The course title is Computer Networks with credit hours being 3-0

Course Description

• Covers TCP/IP layers
• Includes Network architectures, Application layer protocols like HTTP and FTP
• Includes Transmission layer protocols: TCP and UDP
• Includes Network Layer services: routing protocols IPV4 and IPV6
• Includes Data link layer services: Error detection and correction, Multiple access Control
• It examines the Open Systems Interconnection (OSI) reference model (ISO/IEC 7498-3:1997 et al) and Transmission Control Protocol/Internet Protocol (TCP/IP)

Course Objectives

• Use basic computer networking terminology
• Define the roles of major components in computer networks and the Internet: host, router, network application, protocol, and network services
• Calculate network performance metrics like packet delay, link utilization, and throughput
• Describe operations of Internet protocols like HTTP, FTP, DNS, DHCP, TCP, UDP, and IP
• Describe principles of reliable data transfer using algorithms like TCP
• Differentiate between virtual-circuit networks and datagram networks
• Explain the IP protocol operation and IP address assignment facilitating packet routing across the network

Course Syllabus

• Weeks 1 and 2: Computer Networks and the Internet and Chapter 1: Introduction
• Weeks 3 and 4: Application Layer and Chapter 2: The Application Layer
• Weeks 5 and 6: Transport Layer and Chapter 3: The Transport Layer
• Week 7: Midterm Exam
• Weeks 8, 9, and 10: Network Layer, Chapter 4: The Network Layer: Data Plane, and Chapter 5: The Network Layer: Control Plane
• Weeks 11, 12, 13, and 14: Link Layer and Chapter 6: The Link Layer and LANs
• Week 15: Final Exam

Chapter 1: Introduction

• Goals include feel and terminology
• Overview includes what is the Internet and protocols, network edges, physical media, network core, losses, security, protocol layers, and history
• Roadmap includes what is the Internet, network edge, network core, delay, security, protocol layers and history

What is the Internet

• Nuts and bolts view involves billions of connected computing devices with hosts running apps using communication links that have specific bandwidth
• Internet is a network of networks
• Protocols control receiving and sending messages
• Has Internet standards, e.g. TCP, IP, HTTP, Skype, 802.11
• Has RFC: Request for comments and IETF: Internet Engineering Task Force
• Service view features infrastructure for applications and programming interfaces
• Provides web, VoIP, email, games, e-commerce and social nets
• Hooks send and connect applications using analogs to the postal service

Protocols

• Human protocols involve actions like asking time, where there are messages sent and interactions between people
• Network protocols involve messages and information being formatted and followed to allow network entities to communicate in transmittion

Network Structure

• Network edge involves clients and servers in data centers
• Physical media and access networks involve wired and wireless communication links
• Network core involves interconnected networks and internetworked routers
• Access networks connect end systems to edge routers
• Residential/institutional and mobile access networks are used
• Important considerations include bandwidth and whether its shared
• DSL uses existing telephone lines to central office DSLAM
• Upstream is less than 2.5 Mbps and downstream is less than 24 Mbps
• Fiber and coax cables use cable headends with channels in different frequency bands where data gets transmitted
• Hybrid Fiber Coax features asymmetric capabilities, e.g. 30Mbps downstream rate
• Unlike DSL, cable shares access to the network at headends
• Home networks include wireless devices connected to central offices
• Enterprise networks use ethernet at 10Mbps to 10Gbps transmission rates
• Wireless networks include shared access to routers via access points
• Wireless LANs support 11 - 450 Mbps transmission and wide area cellular access operates between 1 -10 Mbps
• 3G and 4G use LTE connections
• Hosts send data in packets
• Hosts break message into L bit chunks and transmit at rate R

Physical Media

• Bits propagate between transmitter/receiver pairs along physical links
• Guided media involves propagation of solid mediums like fiber
• Unguided media transmits signals freely, e.g. radio
• Twisted pair cable features insulated wires at 100 Mbps - 10 Gbps
• Coaxial cable uses concentric conductors and bidirectional connections
• Fiber optic cables transmit light pulses and support high-speed operations with low losses
• Radio transmits signals in the electromagnetic spectrum using reflection and frequencies

Network Core

• The network core is a mesh of interconnected routers
• Packet Switching involves breaking messages into data packets to forward between routers
• Forwarding packets includes entering packets upon arrival prior to transmission
• Packet switching takes L/R bits to transmit such as it one way transmissions are valued at 5 seconds
• Arrival rate dictates transmission rate depending on queueing
• Two core functions are moving algorithms and forwarding packets to output

Alternative Core - Circuit Switching

• Resources allocated at the end of connections for calls coming in and circuits are required
• Circuits are idle when not in action, unlike shared networks
• Circuit switching can occur with Frequency Division Multiplexing (FDM) or Time Division Multiplexing (TDM)

Comparision Between Packet and Circuit Switching

• Packet switching allows more network users
• Circuit switching has a call setup, while switching congestion may cause delays
• Packet Switching still must solve issues bandwidth guarentee for media
• Internet structure is a network of networks
• End systems connect by ISPs
• Access ISPs must be interconnected because evolution relies on economic and policy conditions
• Direct Connection is not scalable for new access networks
• ISPs have economic agreements that connect transit networks together
• Competitors which interconnect Internet Exchange points, which sometimes have regional networks
• Content provider networks can also have their own networks such as Google
• Small networks include Tier 1 ISPs like Google and international data which often bi-pass tier 1s
• Points of presence are from and to the backbone of interactions