AT&T, for instance, is in the process of upgrading its network to deploy SONET rings in Sacramento, San Francisco, Atlanta, Washington, and Baltimore at a cost of about $2.7 billion [10-23]. Sprint in 1994 announced the completion of the Silicon Valley Test Track, linking seven companies and several learning institutions to test ATM switching technologies. The initial OC-1 ring was planned to be upgraded to OC-3 in early 1995 and to OC-12 later in the year [10-24]. More recently, Sprint deployed the first international SONET ring, linking four cities in New York and three in Canada. The capacity of that OC-48 SONET ring will be increased to 10 Gbps through the use of Wave Division Multiplexing (WDM) equipment in order to derive four OC-48 channels [10-25]. MCI recently announced a similar nonstandard SONET deployment to provides 10 Gbps between Washington, DC and Richmond, VA. The SONET ring will be used in support of MCIs e-mail messaging service [10-26]. Finally, AT&T announced in May 1996 plans to beef up its network with WDM equipment to realize 20 Gbps over OC-48 SONET fiberan eight-fold increase [10-27].
SONET also finds application in campus environments, including not only institutions of higher learning, but also business campuses. In such an environment, significant volumes of data and image information often are transmitted between buildings (e.g., mainframe-to-mainframe). In the future, internetworking of Gbps LANs will be requiredin such applications, fiber makes sense and SONET makes even more sense. Mission-critical environments, such as airports, find the redundancy and resulting resiliency of a SONET infrastructure to be particularly attractive.
As interesting and recent application of SONET technology is that of the 1996 Summer Olympics in Atlanta. BellSouth, the incumbent LEC, deployed 40 OC-48 SONET rings to transport CD-quality voice, broadcast-quality video, and data simultaneously to nine cities in the Greater Atlanta area where the 26 various competitions took place. All information flowed through the SONET pipes, including competition results, accreditation, data, voice, and video. The uncompressed digital video signals traveled to the International Broadcast Center, where the signals were sold to other broadcasters and produced 40 worldwide video satellite feeds for 3,000 hours of Olympic coverage [10-28].
Independent end users can gain access to SONET transmissions that are offered by a number of the LECs (Ameritech, BellSouth, Pacific Bell and US West), IXCs (AT&T, LDDS Worldcom, and Sprint) and CAPs (MFS and TCG). The costs, however, can be high; coast-to-coast SONET circuits at 155 Mbps (OC-3) are quoted at almost $425,000 per month [10-29].
References
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