Download An Introduction to Computer Networks by Peter L Dordal, A free general textbook about computer networking, complete with diagrams and exercises. it's appropriate because the primary text for an undergraduate or introductory graduate course in computer networking, or as a supplemental text for a wide style of network-related courses. Download the pdf from below to explore all topics and start learning.

BOOK CONTENTS-

1 An Overview of Networks
2 Ethernet
3 Other LANs
4 Links
5 Packets
6 Abstract Sliding Windows
7 IP version 4
8 IP version 6
9 Routing-Update Algorithms
10 Large-Scale IP Routing
11 UDP Transport
12 TCP Transport
13 TCP Reno and Congestion Management
14 Dynamics of TCP
15 Newer TCP Implementations
16 Network Simulations: ns-2
17 The ns-3 Network Simulator
18 Mininet
19 Queuing and Scheduling
20 Quality of Service
21 Network Management and SNMP
22 Security
23 Bibliography
24 Selected Solutions