Previewing Data Center Components

The word infrastructure has been used several times in this book so far, most often in reference to the electrical and data cabling provided to Data Center cabinet locations. In truth, it is a broader term that traditionally applies to seven basic Data Center facility systems: physical space, raised flooring, in-room electrical, standby power, data cabling, cooling, and fire suppression. (The term can also apply to the collection of networking devices in a Data Center, but si..

Updating the Routing Table in Passive Mode with DUAL

When a path is lost, DUAL first looks in the topology table for a feasible successor. If one is found, the router stays in passive mode (passive, in this sense, means that the router is not actively querying for an alternative path).  Figure 3-5 provides an example network.  Figure 3-5. The Use of Feasible and Advertised Distance—Passive Mode   The following list explains Figure 3-5 with the metrics and actions that EIGRP takes in determining the path..

Changing Privilege Level of IOS Commands

Cisco routers support sixteen privilege levels, ranging from zero to fifteen. By default, Cisco assigns commands to only three of these privilege levels: zero, user, and enable. There are five commands with privilege level zero: disable, enable, exit, help, and logout. The user level (privilege level 1) has a wide variety of commands available that cannot alter the router's configuration. Enable mode (privilege level 15), by contrast, allows complete access to all router comm..

Supported Cisco Platforms for Frame Relay to ATM Interworking

This section presents an overview of the Cisco router platforms that support the Frame Relay to ATM Interworking feature. During the early development stage, not all Cisco router platforms offer the support for the Frame Relay to ATM interworking function. The early supported router platforms include the Cisco MC3810, the Cisco 2600 series, the Cisco 3600 series, and the Cisco 7200 series. For Cisco IOS software support, the Frame Relay to ATM Interworking feature is availab..

Providing a Backup to Frame Relay Virtual Circuits

Using secondary connections to back up the main Frame Relay virtual circuits allows organizations to continue their business operations by ensuring network connectivity in the event of failures to the primary connections. Provisioning a secondary backup connection to the primary Frame Relay virtual circuit can prevent a single point of failure in the network. Some Frame Relay carriers offer network redundancy services by provisioning a secondary virtual circuit as a backup t..