Endpoints (End Devices)
Learn what end devices (endpoints) are in CCNA. Understand roles, routing, addressing, and security of endpoints to build a strong networking foundation.
Data Link Layer
In this lesson, we examine the 2nd layer of the OSI model, called the Data Link Layer. Its main job is to move data between two devices that are directly connected at the physical layer. It adds framing, error detection, and MAC addressing.
Network Layer
Explore the Network Layer (Layer 3) of the OSI model, focusing on IPv4 and IPv6, IP addressing, routing, and how routers forward packets using destination IPs.
Transport Layer
In this lesson, we examine the 4th layer of the OSI model called the Transport Layer. There are a few protocols that operate at the Transport layer. However, by far the most widely used ones are TCP and UDP.
Application Layer
In this lesson, we examine the top three layers of the OSI model, layers 5, 6, and 7, called the Application, Presentation, and Session.
Network Fundamentals
Learn networking basics with the Network Fundamentals course. Build a CCNA-ready foundation through clear lessons, labs, and real Cisco practice.
Understanding the OSI model
In this lesson, we explain what the OSI model is in an easy and understandable language. It is one of the most important concepts in networking, so we break it down into pieces to help you understand exactly what its purpose is.
Standard Numbered ACL
Learn how Standard Numbered IPv4 ACLs work. This lesson covers packet matching, wildcard masks, implicit "deny any," and configuring ACLs with global or named-style commands.
ACL Basics
ACL Basics: Learn how access control lists match and manage traffic on Cisco devices.
HTTP and DNS essentials
This lesson continues our exploration of TCP/IP protocols that are important in the context of Access Control Lists (ACLs). It explores the most common use of the Internet: browsing the World Wide Web (www).