Overview
This lecture covers the main types of network devices found in a data center, their purposes, and how they interact to manage data flow, security, storage, and wireless connectivity.
Network Routing and Switching Devices
- Routers move data between different IP subnets, connecting LANs (Local Area Networks) and WANs (Wide Area Networks).
- Routers operate at OSI Layer 3 (network layer) using IP addresses to direct traffic.
- Layer 3 switches combine switching and routing functions within the same device.
- Network switches operate at OSI Layer 2 (data link layer) using MAC addresses to forward traffic.
- Switches typically use ASICs (Application-Specific Integrated Circuits) for fast hardware processing.
- Power over Ethernet (PoE) allows switches to supply power over Ethernet cables.
Network Security Devices
- Firewalls control traffic using port numbers and can filter based on application with Next Generation Firewalls (NGFW).
- NGFWs often support VPNs (Virtual Private Networks) for encrypted communication and can provide Network Address Translation (NAT).
- Firewalls may support dynamic routing protocols and operate as routers (Layer 3).
- Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS) monitor and respond to network attacks.
- IDS alerts to threats, while IPS can actively block malicious traffic.
Load Balancers and Proxies
- Load balancers distribute traffic across multiple servers to maximize uptime and optimize server use.
- Load balancers can perform TCP/SSL offloading and cache frequently accessed data.
- Proxies sit between users and the Internet to process requests, provide access control, filter content, and cache data.
- Transparent proxies work without manual configuration on user devices.
Storage Solutions
- Network Attached Storage (NAS) provides file-level access, transferring entire files over the network.
- Storage Area Networks (SAN) offer block-level access, allowing more efficient modifications to large files.
- NAS and SAN are usually placed on high-bandwidth, isolated networks for performance.
Wireless Networking
- Access points provide wireless connectivity, bridging wireless and wired (Ethernet) networks, and operate at OSI Layer 2.
- Multiple access points are managed in large environments to ensure seamless wireless coverage.
- Wireless LAN controllers provide centralized management and automatic deployment/configuration of access points.
Key Terms & Definitions
- Router — Device that directs data between different IP subnets at OSI Layer 3.
- Switch — Device forwarding data at OSI Layer 2 using MAC addresses.
- Firewall — Security device filtering network traffic based on rules.
- NGFW (Next Generation Firewall) — Advanced firewall capable of application-level filtering and additional security features.
- IDS/IPS — Intrusion Detection/Prevention Systems for monitoring and blocking attacks.
- Load Balancer — Distributes network/website traffic across multiple servers.
- Proxy — Intermediary device for client-server communication, often used for security and caching.
- NAS (Network Attached Storage) — File-level centralized storage device.
- SAN (Storage Area Network) — Block-level centralized storage network.
- Access Point — Device enabling wireless devices to connect to a wired network.
- Wireless LAN Controller — Centralized access point management device.
Action Items / Next Steps
- Review the characteristics and functions of each network device type discussed.
- Prepare for quiz on definitions and OSI layers associated with each device.
- Read next chapter on virtualized network appliances.