CCNA
Cisco Certified Network Associate certification resources
Mastering Duplex and Speed Settings for Ethernet Switches in 2025
Duplex and Speed settings are the most basic settings for each switch port. By default, Cisco switches will auto-negotiate the speed and duplex settings. However, the switch port and connected devices, such as a computer or another switch, can mismatch the duplex and speed settings. Two types of duplex settings are used for communications on an...
Master Memory Buffering on Cisco Switch: Techniques for 2026 Networks
Ethernet switches employ memory buffering to manage data traffic efficiently, ensuring frames (data units) are temporarily stored when destination ports face congestion. Effective buffering is crucial to prevent frame loss, which can degrade network performance, increase latency, and trigger retransmissions, ultimately impacting user experience and reliability. This article explores buffering methods, their evolution, and their...
Switching Fundamentals – Everything to Know
An Ethernet switch is a Layer 2 device. Therefore, the switch uses MAC addresses for switching decisions. It is unaware of the protocol being carried in the data portion of the frame, such as an IPv4 packet. The Ethernet hub repeats bits out of all ports except the incoming port, but an Ethernet switch consults...
Address Resolution Protocol (ARP)
The source host uses Address Resolution Protocol (ARP) to determine the destination MAC address. Although the destination MAC address can be a unicast, broadcast, or multicast, the source MAC address must always be unicast. Every device with an IP address on a network also has an Ethernet MAC address. When a device sends an Ethernet...
Mastering Unicast, Multicast, and Broadcast Addresses in 2025
In Ethernet, Multicast, and Broadcast Addresses always describe a group of recipients. However, the unicast explains communication where data is sent from one point to another. Unicast Address A unicast address means a packet has been sent from a single source to a specific destination. All Ethernet and IP networks support unicast transmission. A unicast...
Understanding MAC Addresses: Structure, Importance, and How to Find Them in 2025
A media access control address, or a device’s MAC address, is a worldwide unique identifier assigned to a network interface controller. It is also known as “hardware address” or “physical address” and is very important for communication within network segments. Most IEEE 802 network technologies, including Ethernet, Wi-Fi, and Bluetooth, use a Media Access Control address for within-network...
Ethernet Frame Structure: A Guide to IEEE 802.3 in 2025
In 2025, the Ethernet frame structure, defined by IEEE 802.3, is the backbone of wired and wireless networking, enabling reliable data transfer in everything from smart homes to data centers. This guide explores the components of an Ethernet frame, their roles, and their relevance in modern networks like 400GbE and IoT. Overview of Ethernet Frame...
Understanding LLC and MAC Sublayers in the Data Link Layer (2025)
In 2025, the Data Link Layer is critical for reliable network communication, enabling devices to transfer data efficiently across wired and wireless networks. Its two sublayers—Logical Link Control (LLC) and Media Access Control (MAC)—play distinct roles in framing, addressing, and error control. This guide explores their functions, differences, and relevance in modern networking, from Ethernet...
Ethernet Standards: The Backbone of Modern Networking in 2025
In 2025, Ethernet standards remain the cornerstone of reliable, high-speed networking for homes, businesses, and data centers. From streaming 8K videos to powering smart cities, Ethernet’s balance of speed, affordability, and scalability makes it the go-to technology for wired networks. This guide explores Ethernet’s evolution, key standards, and how to choose the right one for...
Network Interface Card (NIC) and Ethernet: Essential for Modern Networking (2025)
A Network Interface Card (NIC), also known as an Ethernet card, is a hardware component that enables a computer to connect to a network, such as a home network or the Internet, using an Ethernet cable with an RJ-45 connector or wireless technologies. Network Interface Cards provide a dedicated, full-time connection to a network, and...