Network Devices OB 1.2

Physical Appliances

Dedicated hardware devices that perform specific network functions. High performance, reliable, expensive.

Virtual Appliances

Software-based solutions that run on virtual machines. High flexibility, cost effective, less performance.

Routers

Devices that connect networks with IP addresses and can also provide security, firewalls, and VPN.

Switches

Data Link Layer devices that connect devices on the same network. They forward data frames between devices based on MAC addresses.

Collision Domain

A network segment where data packets can collide

Firewalls

Monitors incoming and outgoing network traffic, Can be software or hardware. Sets a barrier between the internal and external network.

IDS/IPS

Systems that monitor network and/or system activity for malicious activities or policy violations and can operate at multiple layers

Intrusion Detection System (IDS)

A system that detects malicious network activity using signature detection and anomalous behavior analysis but does not take action to block it

Intrusion-Prevention System (IPS)

A system that actively drops malicious packets or connections based on configured rules. Operate at multiple layers.

Load Balancer

A device that prevents a single server from being overwhelmed by distributing incoming traffic across multiple servers. Operates at various layers of the OSI Model.

Proxy Server

An intermediary device between a user's device and the internet that forwards client requests and returns responses. Often implemented on firewalls.

Proxy Server Functions

Provides content caching,

Network Attached Storage (NAS)

A dedicated file storage device accessible to users over the network. Scalable and cost-effective.

Storage Area Network (SAN)

Dedicated (has its own switch) high-speed network that provides access to consolidated block-level storage. Used in enterprise environments for storage solutions and data management.

Access Point (AP)

A Data Link layer device that allows wireless devices to connect to wired networks and extends the wireless coverage of a network

Wireless LAN Controller (WLC)

A centralized device that manages wireless access points. Configurations are set at the WLC not individual APs.

Content Delivery Network (CDN)

A globally distributed network of proxy servers that cache content in multiple locations (edge servers) worldwide to reduce latency for users

How CDNs Work

Users upload a video to the origin server. Origin server then sends that to the edge servers. When users want to stream video they connect to the closest and fastest edge server instead of to the origin server.

Virtual Private Network (VPN)

A technology that creates a safe and encrypted connection between two networks over a less secure network

Quality of Service (QoS)

A set of technologies and policies used to assign different priorities to network traffic

Time To Live (TTL)

A field in the header of IP packets indicating the maximum time or number of hops a packet is allowed to traverse before being discarded to prevent indefinite looping. Routers decrement the TTL and the packet is dropped when TTL reaches zero