The latest articles on DEV Community by Iwasnever-here (@iwasneverhere). https://dev.to/iwasneverhere https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3333230%2Fa4aec0fa-a653-458b-a079-46926cc7ca54.jpeg https://dev.to/iwasneverhere en Iwasnever-here Sun, 10 Aug 2025 16:53:35 +0000 https://dev.to/iwasneverhere/essential-networking-devices-roles-functions-and-key-details-3b6b https://dev.to/iwasneverhere/essential-networking-devices-roles-functions-and-key-details-3b6b <h2> Router </h2> <ul> <li> <strong>Role</strong>: routes traffic between different IP subnets</li> <li> <strong>Details</strong>: <ul> <li>OSI layer 3 device</li> <li>Routers integrated into switches are sometimes called layer 3 switches</li> <li>connects diverse network types: LAN, WAN, copper, fibre</li> </ul> </li> </ul> <h2> Switch </h2> <ul> <li>Role: performs bridging in hardware using Application-Specific Integrated Circuits (ASICs), forwards data based on data link (MAC) address</li> <li> <strong>Details</strong>: <ul> <li>OSI layer 2 device</li> <li>many ports and advance features</li> <li>core component of enterprise networks</li> <li>may provide Power over Ethernet (PoE)</li> <li>some switches include layer 3 (routing) functionality</li> </ul> </li> </ul> <h2> Firewall </h2> <ul> <li> <strong>Role</strong>: acts as a barrier filtering traffic by port number, protocol or application</li> <li> <strong>Details</strong>: <ul> <li>can encrypt traffic and provide VPN between sites</li> <li>most operate at layer 3 (can function like routers)</li> <li>often placed at network ingress/egress points</li> <li>support Network Address translation (NAT)</li> <li>may support dynamic routing protocols</li> </ul> </li> </ul> <h2> IDS &amp; IPS </h2> <ul> <li> <strong>Role</strong>: IDS detects intrusions and raises alerts, IPS detects and prevents intrusions before they enter the network</li> <li> <strong>Details</strong>: <ul> <li>monitor network traffic for suspicious activity</li> <li>identify attacks inbound to the network</li> <li>can detect exploits like buffer overflow, cross-site scripting and other vulnerabilities</li> </ul> </li> </ul> <h2> Load Balancer </h2> <ul> <li> <strong>Role</strong>: distributes network or application traffic across multiple servers or devices to improve performance and availability</li> <li> <strong>Details</strong>: <ul> <li>manages multiple servers (web farms, database farms)</li> <li>transparent to end users</li> <li>not effected by server outages</li> <li>very fast convergence</li> </ul> </li> <li> <strong>Functions</strong>: <ul> <li>configurable load distribution</li> <li>TCP offload (handles protocol overhead)</li> <li>SSL offload (handles encryption/decryption)</li> <li>caching for faster responses</li> <li>prioritising traffic (QoS)</li> <li>content switching (application-centric balancing)</li> </ul> </li> </ul> <h2> Proxy server </h2> <ul> <li> <strong>Role</strong>: intermediary between user and external networks, forwarding requests on behalf of users</li> <li> <strong>Details</strong>: <ul> <li>useful for caching, access control, URL filtering, content scanning</li> <li>explicit proxies require client configuration</li> <li>transparent proxies are invisible to clients</li> </ul> </li> </ul> <h2> Network attached storage (NAS) </h2> <ul> <li> <strong>Role</strong>: provides file-level access to shared storage over server</li> </ul> <h2> Storage Area Network (SAN) </h2> <ul> <li> <strong>Role</strong>: provides block level access to storage, appearing as local disk to host</li> <li> <strong>Details</strong>: <ul> <li>efficient reading and writing</li> <li>requires high bandwidth, often runs on isolated high-speed networks</li> </ul> </li> </ul> <h2> Access Point (AP) </h2> <ul> <li> <strong>Role</strong>: enables wireless communication and connects wireless clients to the wired network</li> <li> <strong>Details</strong>: <ul> <li>OSI layer 2 device</li> <li>acts as bridge to extend wired network wirelessly</li> <li>not the same as wired router</li> </ul> </li> </ul> <h2> Wireless Network </h2> <ul> <li> <strong>Role</strong>: a network environment composed of multiple access points covering one or more locations</li> <li> <strong>Details</strong>: <ul> <li>pervasive convergence with many APs</li> <li>configurations may vary across sites (access points, security...)</li> </ul> </li> </ul> <h2> Wireless LAN controller </h2> <ul> <li> <strong>Role</strong>: centralised management platform for multiple access points </li> <li> <strong>Details</strong>: <ul> <li>provides a single management interface ("pane of glass")</li> <li>deploys and configures new APs remotely</li> <li>monitors performance and security</li> <li>reports on AP usage</li> <li>usually proprietary and paired with specific AP brands</li> </ul> </li> </ul> Iwasnever-here Sat, 09 Aug 2025 18:22:21 +0000 https://dev.to/iwasneverhere/osi-model-7-layers-explained-5c67 https://dev.to/iwasneverhere/osi-model-7-layers-explained-5c67 <h2> Overview </h2> <p>the OSI (Open Systems Interconnection) model is a framework that describes the broad overview of how data transverses our systems. It divides networking into 7 layers, each with different responsibilities</p> <h2> layer summary: </h2> <div class="table-wrapper-paragraph"><table> <thead> <tr> <th>layer</th> <th>name</th> <th>description</th> <th>example</th> </tr> </thead> <tbody> <tr> <td>7</td> <td>application</td> <td>layer we see - network services to end users</td> <td>HTTP, FTP, DNS, POP3</td> </tr> <tr> <td>6</td> <td>presentation</td> <td>character encoding, application encryption- combines with application layer</td> <td>SSL/TLS</td> </tr> <tr> <td>5</td> <td>session</td> <td>Manages communication between devices</td> <td>control protocols, tunnelling protocols</td> </tr> <tr> <td>4</td> <td>transport</td> <td>transport from one device to another</td> <td>TCP, UDP</td> </tr> <tr> <td>3</td> <td>network</td> <td>routing and addressing</td> <td>IP addresses, routers, packets</td> </tr> <tr> <td>2</td> <td>data link</td> <td>physical addressing, switching, data link control protocols</td> <td>MAC address, frames, switches</td> </tr> <tr> <td>1</td> <td>physical</td> <td>signalling, cabling, connectors</td> <td>cables, fibre, connectors, electrical signals</td> </tr> </tbody> </table></div> <h2> How to remember layer order: </h2> <p><strong>A</strong>ll <strong>P</strong>eople <strong>S</strong>eem <strong>T</strong>o <strong>N</strong>eed <strong>D</strong>ata <strong>P</strong>rocessing</p> <p>(layer 7 to layer 1)</p> <h2> Layer details: </h2> <h3> Layer 1 - Physical </h3> <ul> <li>Role: signalling, cabling, connectors</li> <li>examples: cables, fibre optics, electrical signals</li> </ul> <h3> Layer 2 - Data Link </h3> <ul> <li>Role: data link control protocols (MAC) - "switching layer"</li> <li>Examples: Frame, MAC address, EUI-48, EUI-64, switches</li> </ul> <h3> Layer 3 - Network </h3> <ul> <li>Role: routing, logical addressing, fragmenting frames to traverse different networks - "routing layer"</li> <li>Examples: IP addresses, routers, packets</li> </ul> <h3> Layer 4 - Transport </h3> <ul> <li>Role: transport from one device to another - "post office"</li> <li>Example: TCP, UDP</li> </ul> <h3> Layer 5 - Session </h3> <ul> <li>Role: communication management between devices</li> <li>Example: control protocols, tunnelling protocols</li> </ul> <h3> Layer 6 - presentation </h3> <ul> <li>Role: character encoding, application encryption - combines with the application layer</li> <li>Examples: SSL/TLS</li> </ul> <h3> Layer 7 - Application </h3> <ul> <li>Role: the layer user directly interacts with - provides network service to the user</li> <li>Examples: HTTP, FTP, DNS, POP3</li> </ul> networkfundamentals