IP addresses come in two forms: public addresses, which are assigned by a central network authority and may be used to reach systems located across the Internet and private addresses, which are available for anyone’s use but may only be used on local networks and will not work across the Internet. Learn the differences between public and private IP addresses and the use of Network Address Translation (NAT).
- [Narrator] Networks carry all types of data over distances short and far. Whether it's a trans-Atlantic video conference or an e-mail across the room, many different networks carry the ones and zeroes that make communications work. Switches and routers are the core building blocks of these networks. Network engineers use switches to create networks. These are simple looking devices, such as the switch shown here, that contain a large number of network ports. Switches may be very small with eight or fewer ports, or they can be quite large with 500 or more ports.
The switch shown here is a typical 48 port switch. Switches are normally hidden away inside wiring closets and other secure locations. Each switch port is connected to one end of a network cable. Those cables then disappear into special pipes, known as conduits, for distribution around a building. When the cable reaches the final destination, it usually terminates in a neat looking wall face plate, like the one shown here. This provides an easy way for users and technicians to connect and disconnect computers from the network without damaging the cables inside the wall or having unsightly unused wires lying around the room.
Some devices directly connect to switch ports through the use of wired networks. Many other devices don't use wires, but instead depend upon radio based wireless networks. These networks are created by wireless access points like the one shown here. These APs as they're called contain radios that send and receive network signals to mobile devices. The AP itself has a wired connection back to the switch, allowing wireless devices to connect to the rest of the network. Switches do create networks, but they're limited to creating local networks.
Routers play a higher level role, connecting networks together by serving as a central aggregation point for network traffic heading to or from a large network. The router serves as the air traffic controller of the network, making decisions about the best paths for traffic to follow as it travels to its final destination. Routers also perform some security functions, using access control lists to limit the traffic that may enter or leave a network based upon the organization's security policies.
Routers come in many different sizes, engineered to support different size networks. These two network building blocks play an important role in connecting systems together to create enterprise networks.
Learn about communication and networking best practices, including TCP/IP networking, network security devices, and secure network design and management. Instructor and cybersecurity expert Mike Chapple also includes coverage of converged protocols, network encryption, and wireless networking. You can find Mike's companion study books for this series at the Sybex test prep site and review the complete CISSP Body of Knowledge at https://www.isc2.org/cissp-domains/default.aspx.
- IP addressing
- Switches and routers
- Content distribution networks
- Designing secure networks
- Specialized networking
- Managing secure networks
- Working with virtualized networks like SDNs
- Detecting and preventing network attaches
- Transport encryption
- Wireless networking
- Host security