diff --git a/src/1-network-fundamentals.md b/src/1-network-fundamentals.md new file mode 100644 index 0000000..ecd48d3 --- /dev/null +++ b/src/1-network-fundamentals.md @@ -0,0 +1,106 @@ +# Network Fundamentals + +This section covers the fundamental concepts of networking, including network components, topologies, cabling, basic protocols, and virtualization. + +## 1.1 Network Components + +A network is made up of various interconnected devices that work together to enable communication. Key components include: + +* **Routers:** Direct network traffic between different networks. They operate at Layer 3 (Network Layer) of the OSI model and use IP addresses to make forwarding decisions. +* **Layer 2 Switches:** Connect devices within the same local area network (LAN). They operate at Layer 2 (Data Link Layer) and use MAC addresses to forward frames. +* **Layer 3 Switches:** Combine the functions of Layer 2 switches and routers. They can perform both MAC-based switching and IP-based routing. +* **Next-Generation Firewalls (NGFWs):** Provide advanced security features like intrusion prevention, application control, and malware protection. +* **Intrusion Prevention Systems (IPSs):** Detect and block malicious network activity. +* **Access Points (APs):** Provide wireless connectivity for devices. +* **Controllers:** Manage and control network devices. Examples include Cisco DNA Center for wired and wireless networks and Wireless LAN Controllers (WLCs) specifically for wireless networks. +* **Endpoints:** Devices that connect to the network, such as computers, laptops, smartphones, and tablets. +* **Servers:** Provide services to other devices on the network, such as file sharing, email, and web hosting. +* **Power over Ethernet (PoE):** Allows network cables to carry electrical power to devices like APs and IP phones. + +## 1.2 Network Topology Architectures + +Network topology refers to the arrangement of network devices and connections. Common architectures include: + +* **Two-Tier:** A simple design with two layers: the access layer (where end devices connect) and the distribution/core layer (which provides routing and other services). +* **Three-Tier:** A more scalable design with three layers: access, distribution, and core. This separation of functions improves performance and manageability. +* **Spine-Leaf:** A modern data center architecture that provides high bandwidth and low latency. It uses a mesh topology between spine switches and leaf switches. +* **WAN:** Wide Area Network connecting geographically dispersed networks. +* **Small Office/Home Office (SOHO):** Small-scale networks for homes or small businesses. +* **On-Premise and Cloud:** Networks can be located on-site (on-premise) or in the cloud (using services from providers like AWS, Azure, or GCP). + +## 1.3 Physical Interface and Cabling Types + +* **Single-Mode Fiber:** Used for long-distance, high-bandwidth connections. +* **Multimode Fiber:** Used for shorter distances and lower bandwidth requirements. +* **Copper:** Commonly used for Ethernet connections. Types include unshielded twisted-pair (UTP) and shielded twisted-pair (STP). +* **Ethernet Shared Media:** Multiple devices share the same cable (e.g., hubs). +* **Point-to-Point:** A dedicated connection between two devices (e.g., switches connected directly). + +## 1.4 Interface and Cable Issues + +Common issues include: + +* **Collisions:** Occur on shared media networks when multiple devices try to transmit simultaneously. +* **Errors:** Can be caused by faulty cables, connectors, or network interface cards (NICs). +* **Duplex Mismatch:** Occurs when one device is configured for full-duplex (can send and receive simultaneously) and the other for half-duplex (can only send or receive at a time). +* **Speed Mismatch:** Occurs when devices are configured for different speeds (e.g., 10 Mbps vs. 100 Mbps). + +## 1.5 TCP vs. UDP + +* **TCP (Transmission Control Protocol):** A reliable, connection-oriented protocol. It provides error checking, flow control, and ordered delivery of data. +* **UDP (User Datagram Protocol):** A connectionless protocol. It's faster than TCP but doesn't guarantee delivery or order of data. + +## 1.6 IPv4 Addressing and Subnetting + +IPv4 uses 32-bit addresses to identify devices on a network. Subnetting divides a network into smaller subnetworks to improve efficiency and security. + +## 1.7 Private IPv4 Addressing + +Private IP addresses are used within internal networks and are not routable on the public internet. Common private address ranges include: + +* 10.0.0.0/8 +* 172.16.0.0/12 +* 192.168.0.0/16 + +## 1.8 IPv6 Addressing and Prefixes + +IPv6 uses 128-bit addresses, providing a much larger address space than IPv4. Prefixes define the network portion of an IPv6 address. + +## 1.9 IPv6 Address Types + +* **Unicast:** Identifies a single interface on a device. Types include: + * Global: Routable on the public internet. + * Unique Local: Similar to private IPv4 addresses. + * Link Local: Used for communication within a local link. +* **Anycast:** Identifies a group of interfaces, and traffic is sent to the nearest one. +* **Multicast:** Used to send data to a group of devices. +* **Modified EUI-64:** A method for automatically generating the interface ID portion of an IPv6 address. + +## 1.10 IP Parameters for Client OS + +Client operating systems (Windows, macOS, Linux) use IP parameters such as: + +* IP address +* Subnet mask (IPv4) or prefix length (IPv6) +* Default gateway +* DNS server addresses + +## 1.11 Wireless Principles + +* **Non-overlapping Wi-Fi Channels:** Wi-Fi channels should be selected to avoid interference. +* **SSID (Service Set Identifier):** The name of a wireless network. +* **RF (Radio Frequency):** Wireless communication uses radio waves. +* **Encryption:** Secures wireless networks by encrypting data. Common encryption protocols include WPA2 and WPA3. + +## 1.12 Virtualization Fundamentals + +* **Server Virtualization:** Allows multiple virtual servers to run on a single physical server. +* **Containers:** Lightweight, isolated environments for running applications. +* **VRFs (Virtual Routing and Forwarding):** Create separate routing tables within a device, allowing for network segmentation. + +## 1.13 Switching Concepts + +* **MAC Learning and Aging:** Switches learn the MAC addresses of connected devices and store them in a MAC address table. Entries are aged out if not used. +* **Frame Switching:** Switches forward frames based on destination MAC addresses. +* **Frame Flooding:** If the destination MAC address is not in the MAC address table, the switch floods the frame out all ports except the one it received it on. +* **MAC Address Table:** A table in a switch that stores MAC addresses and their associated ports. \ No newline at end of file diff --git a/src/SUMMARY.md b/src/SUMMARY.md index 7390c82..8af6352 100644 --- a/src/SUMMARY.md +++ b/src/SUMMARY.md @@ -1,3 +1,3 @@ # Summary -- [Chapter 1](./chapter_1.md) +- [Chapter 1 Network Fundamentals](1-network-fundamentals.md) diff --git a/src/chapter_1.md b/src/chapter_1.md deleted file mode 100644 index b743fda..0000000 --- a/src/chapter_1.md +++ /dev/null @@ -1 +0,0 @@ -# Chapter 1