What This Document Is
This document presents lecture notes from an Introduction to Communication Networks course (ELENG 122) at the University of California, Berkeley. It focuses on the crucial layer of network architecture dedicated to application-level protocols – the systems that enable the everyday functions of the internet. It delves into how applications interact with the underlying network infrastructure to deliver services users rely on. This material provides a foundational understanding of the protocols that govern communication across networks.
Why This Document Matters
This resource is ideal for students enrolled in networking courses, particularly those seeking to solidify their understanding of how applications function *on* a network. It’s beneficial for anyone preparing for exams or quizzes covering application layer protocols, or for those wanting a deeper understanding of the internet’s inner workings. It’s particularly useful when combined with hands-on network programming and simulation exercises, offering a conceptual framework for practical application. Accessing the full content will provide a comprehensive overview of these essential networking concepts.
Topics Covered
* The relationship between application protocols and the core network services.
* A comparison of TCP and UDP transport protocols and their suitability for different applications.
* The Domain Name System (DNS) – its history, features, and hierarchical structure.
* The administrative organization of DNS and the roles of different types of DNS servers.
* An overview of common application layer protocols and their corresponding transport protocols.
* The evolution of host name resolution and the challenges overcome in scaling the internet.
What This Document Provides
* A detailed exploration of the roles of host-to-host, host-to-network, and network-to-network protocols.
* An explanation of the hierarchical namespace used in DNS and its administrative structure.
* Insights into the functions of Top-Level Domain (TLD) servers and authoritative DNS servers.
* A conceptual overview of how application layer protocols leverage transport layer services.
* A historical context for the development of the Domain Name System.
