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Duration: 3Ìýhours

Welcome to Network Systems Foundations, over the next five weeks you'll explore topics related to network systems. This will center on the layered design of networks, and cover the link layer (Ethernet), network layer (IP), transport layer (TCP, UDP), and application layer (HTTP, gRPC). ÌýWith those as a foundation, you will learn about network security problems and how current solutions work at different layers. We'll start the course Ìýby understanding the Link Layer, comprehending its critical role, and exploring why it's vital in the realm of network communication. You'll explore the intriguing behavior of network switches, investigating how they react when receiving frames with various destination MAC addresses. You'll learn to distinguish between the characteristics of different channel partitioning methods, offering valuable insights into network efficiency. You'll explore the Ethernet Frame Check Sequence (FCS) field, uncovering its role and significance in data integrity. Finally, you'll have the opportunity to put your knowledge to the test by designing and developing Python code that can skillfully manage route announcements and withdrawals, ensuring the efficient maintenance of a routing table.

Duration: 6Ìýhours

This week, you will explore the network layer, which is responsible for routing packets between different networks and deals with logical addressing, routing, and forwarding. Throughout the week, you'll learn about the intricacies of the Internet Protocol (IP) and its pivotal role in orchestrating the efficient routing of data. Then, you will explore the intricate operations of router data planes and the concept of routing, focusing on the distinctions between Routing Link State Protocol and Routing Path Vector Protocol. You will then turn your attention to troubleshooting techniques for resolving network layer issues. At the end of the week, you will be tasked with the development of a Python program that simulates the functionalities of a simplified router akin to those employed in the Border Gateway Protocol (BGP).Ìý

Duration: 4Ìýhours

This week, you will explore the transport layer, which ensures end-to-end communication, error detection, and data flow control, and protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) work at this layer. You'll begin the week with an overview of the transport layer and its relationship with the other layers. Then, you learn about multiplexing and how to efficiently combine multiple data streams into a single channel. Then the TCP protocol will be explored, beginning with the establishment of connections and extending to the nuances of congestion control. The concludes with a programming assignment in Python, where you will analyze a pcap file containing a single TCP flow to determine the maximum bytes in flight—a hands-on exploration of the week's concepts.Ìý

Duration: 5Ìýhours

This week, you will explore the application layer, where application-specific protocols and services reside. It includes protocols for services like email (e.g., SMTP), web browsing (e.g., HTTP), and file transfer (e.g., FTP). You'll begin the week with an overview of the application layer and its relationship with the other layers. Then, you'll explore the Domain Name System (DNS), unraveling its role in translating domain names to IP addresses. A vital aspect of network application development, socket programming, will be discussed, equipping you with the knowledge to facilitate network communication. The week further delves into application protocols, specifically HTTP and gRPC, detailing their structures and functions. This week, you'll have two programming assignments: one to explore gRPC, and the other, a graded assignment, to create a client-server using socket programming for RPC functionality.

Duration: 3Ìýhours

In this final week, you will delve into network security. The week begins with the basics of network security, then focuses on the intricacies of IPsec, securing the network data plane, and the role of RPKI in fortifying the network control plane. You will examine the bedrock of secure communication—TLS/HTTPS, which extends its protective embrace to the transport and application layers. The week will end with a programming assignment where you will create a digital certificate for a web server.

Duration: 2Ìýhours

This module contains materials for the final exam. If you've upgraded to the for-credit version of this course, please make sure you review the additional for-credit materials in the Introductory module and anywhere else they may be found.