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Various internetworking devices offer services that are critical to the network. In this section, I will review three important components and the role each plays in making the network function in a secure fashion.

Firewalls

Firewalls are hardware appliances or special software running on servers that control the flow of traffic between parts of the network. Routers can also be configured to perform this service.

These devices are network security systems that monitor and control the incoming and outgoing network traffic based on predetermined security rules, and they are usually intrusion protection systems (IPSs). The Cisco Adaptive Security Appliance (ASA) firewall typically establishes a barrier between a trusted, secure internal network and the Internet, which is not secure or trusted. Cisco's new acquisition of Sourcefire puts it at the top of the market with Next Generation Firewalls (NGFW) and Next Generation IPS (NGIPS), which Cisco now just calls Firepower. Cisco's new Firepower runs on dedicated appliances, Cisco ASAs, ISR routers, and even Meraki products.

Access Points

These devices allow wireless devices to connect to a wired network and extend a collision domain from a switch and are typically in their own broadcast domain, or what is referred to as a virtual LAN (VLAN). An AP can be a simple standalone device, but today they are usually managed by wireless controllers either in-house or through the Internet.

Wireless Controllers

These are the devices that network administrators or network operations centers use to manage access points in medium to large to extremely large quantities. The WLAN controller automatically handles the configuration of wireless access points and was typically used only in larger enterprise systems. However, with Cisco's acquisition of Meraki systems, you can easily manage a small to medium-sized wireless network via the cloud using its simple-to-configure web controller system.

Exam Essentials

Describe the features of infrastructure components in an enterprise network. These include but are not limited to access points, WLAN controllers, and firewalls. Specific firewall solutions include the Cisco Adaptive Security Appliance (ASA), Next Generation Firewalls (NGFW), and Next Generation IPS (NGIPS), which Cisco now just calls Firepower.