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Phase 3: Switched Ethernet

At least, based on the live experiments, CIBER now had a better idea of capacity requirements. The order called for 10 kiosks to deliver audio and video and 15 to handle audio only. CIBER estimated that they would need 2.6 Mbps of capacity to deliver video to each of 10 workstations and 0.9 Mbps to deliver audio to the other 15. This amounted to 40 Mbps required to meet their needs. They weren't going to get that from a shared Ethernet or even token ring, but switched Ethernet with a 100BASE-T backbone might do the trick, provided that the software was beefed up.

CIBER found a software solution that seemed to work: Starlight's StarWorks, which is a software package that runs on Sun workstations and provides efficient video delivery. For example, with StarWorks, video data is organized in stripes, on separate disks in a disk array. Pulling video from more than one drive speeds up access time and enables StarWorks to stream packets in long groups, cutting back on handshaking with the workstations.

With the software plan in hand, the task was to deploy a 100BASE-T backbone to link the servers and 10BASE-T switched Ethernet to the Macintosh workstations. This would give each workstation a dedicated 10 Mbps link with a 100 Mbps capacity back to the servers. But this phase, too, ran into unexpected problems. The configuration used LANnet hubs that provided both 100BASE-T and 10BASE-T ports, but when these were linked to the SunSPARC servers, many problems cropped up. Working with both the hub and server vendors, it's likely that the problems could eventually have been solved, but the team was running on a tight deadline. On another project, CIBER has integrated Sun servers with Cisco switches. Cisco switches were brought in that supported 25 switched 10BASE-T ports and 9 100BASE-T links.

Figure 1 shows the final configuration. The 25 kiosks are located in two exhibition areas. Each kiosk gets about 100 hours of use per week. Each kiosk includes a speaker and a touch-control monitor that are hooked up to a Macintosh workstation, at distances up to 500 feet. All of the workstations and other network equipment are located in a control room. Once an option is chosen, the signal travels over video cable to the workstation. If video clips are requested, the request goes to one of the servers, which pumps the data down to the workstation. Data move from the server to the switch at 100 Mbps and then to a workstation at 10 Mbps. Each server stores all of the audio and video clips, providing full redundancy. Finally, an HP Vectra with a large-capacity tape drive stores all of the files in backup.

Figure 1

Network configuration for the Rock and Roll Hall of Fame and Museum.

Recently, the museum has extended this networked approach to its Web site (www.rockhall.com), spreading the rock 'n' roll gospel to the networked masses on many platforms. Web users can download the same audio and video clips available to museum visitors and play the clips using Apple's QuickTime. The site provides the QuickTime software for Apple and Windows platforms.

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