1. Basic Network Gear Created by Alex Schatz

2. Hub A hub is a very basic internetworking device. Hubs connect multiple machines together and allow them to connect with the rest of a network. Machines connected to the hub share bandwidth, and are only allowed to transmit information one at a time. Incoming network traffic is sent to all the connected devices, relying on the fact that the intended host will accept it, while others will ignore it. A hub would be best suited for joining a number of close machines together to form a small private network, or connecting a small room of desktops to a switch or router. Hub PC Network 100Mbps 33Mbps A typical 5 port hub with uplink

3. Switch Switches are essentially an improved form of a hub. Bandwidth is not shared between the hosts and communication can be run in full duplex mode, which allows machines to transmit and receive data at the same time. Each host only receives the traffic that is intended for it. Switches can be used in the same situations as hubs, and support a larger number of hosts. Due to the fact that small switches are now relatively inexpensive, hubs can be difficult to find in retail stores. A switch can cost between $10 for a small model, and over $2000 for enterprise models. Network 100Mbps 50Mbps 100Mbps PC Switch PC 50Mbps 100Mbps Hub A simple 5 port switch vs. a 48 port enterprise switch

4. Router Routers are capable of all the features available in switches, however on top of this, routers are the typical starting point for handling layer 3 traffic. Modern routers are capable of assigning IPs to machines, acting as a gateway between networks, protecting your network with a firewall and acting as a wireless access point. Due to the large feature set, routers are more expensive than switches, ranging from $20 for low end consumer products to several thousand dollars for enterprise environments. In homes routers tend to be the only device aside from a modem, in businesses however, routers aggregate networks out to switches. PC Network Switch Router Switch PC A wireless capable home router vs. an enterprise router.

5. Bridge A bridge connects two similar networks to give the appearance that they are one. Bridges are largely transparent for hosts on the network. Many routers have bridging capabilities built in. Bridges tend to cost around the same amount as routers. PC Switch Gateway WAN Router PC Switch Bridge A wireless capable bridge

6. Gateway The purpose of a gateway is to allow devices in one network to interface with another network. The networks that gateways communicate are usually very different and require protocol conversion. Home routers typically act as a gateway, however due to the amount of traffic in enterprise environments a separate gateway server is often used. These servers can also act as a firewall server. PC Switch Router Gateway WAN Gateway PC Switch Router Network B Network A A rack mountable Gateway server

7. Firewall Firewalls are security devices designed to monitor network traffic and block unwanted traffic from entering or exiting the network. In home networks, routers have a software based firewall, much like the one that resides on desktop PCs. Enterprise environments use either a standalone firewall or a software firewall residing on a gateway server. PC Switch Gateway WAN Router Firewall Various firewall devices

8. Wireless AP A wireless access point transmits and receives wireless signals. A standalone wireless AP allows wireless devices to connect to a wired network. Routers typically act as the access point for home networks. A WAP for small businesses such as the one pictured below can cost between $100- $300, however these are intended to support a large number of clients. WAP PC Switch Network A wireless AP

9. Network Example Hub PC WAN Switch Router Switch PC Hub PC Wireless AP PC Switch Gateway & Firewall Server Switch PC Bridge