Drawing Tools Available to Create Your Data Center Layout

Part of creating a productive Data Center is a logical layout of all its constituent parts. From air handlers to electrical panels, sprinkler pipes to server rows, floor tiles to telephones, you must specify not only what components go in your server environment but also where exactly the components are to be located. One of the most effective ways to communicate the layout is the creation of a detailed map of the Data Center. While it is possible to create an informative de..

IPv6 Address Formats

IPv6 addresses have eight quartets of hex digits, separated by colons. Each quartet consists of four hex digits, which together represent 16 bits. The rules for encoding the actual hex values are as follows: ■ Each quartet is separated by a colon (:). ■ In a quartet, leading hex 0s can optionally be omitted. ■ If one or more consecutive quartets are hex 0000, then the set of consecutive all-0 quartets can be represented as a null quartet (::), no matter how many cons..

Voice Services

Voice service over wireless LANs is becoming the killer application that is causing the industry to explode. Many mobile device makers are beginning to include integrated Wi-Fi in smart phones and PDAs along with cellular interfaces, and enterprises are beginning to understand the significant advantages of using voice services, along with data, over wireless LANs. The Cisco Wireless IP Phone 7920, for instance, interfaces with 802.11b access points. Incredible gains in effi..

Integrated Services Digital Network

ISDN is a digital service that enables network users to send and receive data, voice, and video transmissions over a network. ISDN offers a variety of link speeds, ranging from 64 kbps to 2.048 Mbps (including a signaling channel of 64 kbps). With the advent of DSL and cable, ISDN may not be a viable network solution for anything other than a backup link, because of the expense involved. Basic Rate and Primary Rate Interfaces ISDN can be supplied by a carrier in two main fo..

Using Time-Based Access-Lists

To filter application data based on the time of day, use the following commands: Router1#configure terminal Enter configuration commands, one per line.  End with CNTL/Z.Router1(config)#time-range NOSURFRouter1(config-time-range)# periodic weekdays 9:00 to 17:00Router1(config-time-range)#exitRouter1(config)#ip access-list extended NOSURFINGRouter1(config-ext-nacl)# deny   tcp any any eq www time-range NOSURFRouter1(config-ext-nacl)# permit ip any anyRouter1(con..