In July 2001, a group called IEEE 802.3ah Ethernet in the First Mile Task Force (http:// grouper.ieee.org/groups/802/3/efm/public/) was established to provide solutions for the socalled last-mile issue. Currently, a wide variety of protocols provide services to the last mile. They include ISDN, DSL, cable modems, satellite, and broadband wireless solutions, which offer speeds under 10 Mbps. However, existing Intranets use technologies such as Fast and Giga-Ethernet with speed..
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..
To successfully manage any network, timely and accurate information is required. Not only is current and up-to-date information necessary (that is, "snapshots" of the WLAN in its current state), but also historical reporting capabilities are required to help identify trends. Additionally, alerting capabilities are important. WLAN reporting includes three related areas, as described in the following sections: • Standard/systematic reports • &nb..
Hierarchical Queuing Architecture for Frame Relay
When Frame Relay encapsulation is configured for serial interfaces on Cisco routers, two levels of queuing can exist for the serial interfaces. By default, when the Frame Relay interface is congested, the interface-level queue is used to store the excess packets at the interface level until the interface becomes free to send them. In addition, a second level of queuing at the Frame Relay PVC level is possible with Frame Relay Traffic Shaping. NOTE WFQ is the default queuing..
