Computer Networks Course

What you will learn in 8 lessons

1. 1

   Packet Switching and Network Performance

   Start here

   Explain how access networks, packet switching and the network of ISPs carry data, and calculate delay, loss and throughput.

   5 learning goals

   What you will learn

   1. 1.Describe how devices connect at the network edge
   2. 2.Compare packet switching and circuit switching
   3. 3.Explain how ISPs form a network of networks
   4. 4.Calculate delay, packet loss and throughput
   5. 5.Measure network paths with traceroute
2. 2

   Application Layer

   Explain how application protocols such as HTTP, DNS and SMTP work, compare client-server and peer-to-peer designs and write simple socket programs.

   6 learning goals

   What you will learn

   1. 1.Explain how networked applications are organized and what they need from the network
   2. 2.Explain how the web delivers pages with HTTP
   3. 3.Explain how DNS translates names into addresses
   4. 4.Explain how email is sent, delivered and read
   5. 5.Explain how large-scale content is distributed
   6. 6.Write simple client and server programs with sockets
3. 3

   Transport Layer

   Explain multiplexing, UDP and the principles of reliable data transfer, and describe how TCP manages connections, sequence numbers and flow control.

   5 learning goals

   What you will learn

   1. 1.Explain what the transport layer does for applications
   2. 2.Use UDP and judge when it fits
   3. 3.Build reliable data transfer from first principles
   4. 4.Explain how TCP sets up connections and numbers its data
   5. 5.Explain how TCP delivers data reliably and matches the receiver's pace
4. 4

   Congestion Control

   Explain the causes and costs of congestion and how TCP congestion control algorithms share bandwidth fairly.

   6 learning goals

   What you will learn

   1. 1.Explain why networks become congested and what congestion costs
   2. 2.Explain how TCP's classic congestion control adjusts its window
   3. 3.Analyze how competing flows share a bottleneck fairly
   4. 4.Explain how routers signal congestion before their buffers overflow
   5. 5.Compare modern congestion control algorithms: CUBIC and BBR
   6. 6.Explain how QUIC carries congestion control into a new transport
5. 5

   Network Layer Data Plane

   Explain how routers forward packets, how IPv4 and IPv6 datagrams are structured and how NAT and generalized forwarding work.

   5 learning goals

   What you will learn

   1. 1.Explain how a router moves packets toward their destination
   2. 2.Read and reason about IPv4 datagrams
   3. 3.Explain how DHCP and NAT connect hosts to the internet
   4. 4.Compare IPv6 with IPv4 and explain the transition
   5. 5.Explain generalized forwarding, SDN and middleboxes
6. 6

   Routing and the Control Plane

   Compute routes with link-state and distance-vector algorithms and explain how OSPF, BGP and SDN controllers build forwarding tables.

   6 learning goals

   What you will learn

   1. 1.Compute routes with link-state and distance-vector algorithms
   2. 2.Route inside an autonomous system with OSPF
   3. 3.Route between networks with BGP
   4. 4.Explain how an SDN controller builds forwarding tables
   5. 5.Report errors and test paths with ICMP
   6. 6.Manage networks with SNMP, NETCONF and YANG
7. 7

   Link Layer

   Explain error detection, multiple access protocols, Ethernet switching, ARP and VLANs, and how Wi-Fi and cellular networks connect mobile hosts.

   6 learning goals

   What you will learn

   1. 1.Explain what the link layer does and detect transmission errors
   2. 2.Share one channel with multiple access protocols
   3. 3.Address and switch frames in Ethernet LANs
   4. 4.Explain data center networks and follow a web request through every layer
   5. 5.Explain how wireless links and Wi-Fi networks work
   6. 6.Explain how cellular networks connect and move mobile users
8. 8

   Security in Computer Networks

   Explain how cryptography provides confidentiality, integrity and authentication in network protocols, and how TLS, IPsec, firewalls and intrusion detection protect networks.

   6 learning goals

   What you will learn

   1. 1.Use cryptography to keep network messages confidential
   2. 2.Protect message integrity and prove who is communicating
   3. 3.Secure TCP connections with TLS
   4. 4.Protect IP traffic with IPsec and VPNs
   5. 5.Secure wireless access in Wi-Fi and cellular networks
   6. 6.Defend networks with firewalls and intrusion detection