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SONET is not only fast; it's versatile. Voice calls from one office to another can be multiplexed and placed on a SONET fiber along with data. With the bandwidth SONET affords, compression or encapsulation into an IP packet is unnecessary. A single OC-3 connection can carry more than 2,000 uncompressed simultaneous voice calls, and all data types can be multiplexed right beside the calls. Frame relay signals can be taken directly from DS-0 to DS-3 and placed into a SONET frame along with ATM cells from DS-1 up. You won't need separate networks carrying varied data types from office to office, because they can be combined into SONET frames.

Because many of SONET's advantages are unmatched by other Layer 1 protocols--such as the capability to combine data types along with voice calls over a single fiber--installing a SONET network is a smart choice for many businesses. And whether you are calling your national carrier or LEC (local exchange carrier) to provide fiber or calling out the backhoes to run your own, it is important to understand everything involved in how SONET works.

SONET offers bandwidth up to OC-192 (9,953.28 Mbps) and can carry a wide variety of information. SONET also offers exceptional BERs (bit-error rates) of 1x10-10 (1 error in 10 billion bits) compared with copper transmission methods of 1x10-6 (1 error in 1 million bits). Even with these pluses, SONET networks need to be carefully designed to facilitate growth and protection based on your needs.

Backhoe Not Required

Before you start tearing up the street, note that SONET services can be provided by a carrier or LEC that may also help you design your network efficiently (see "No Competition Among Local Providers," page 136, for more information on leasing these services). Everything starts with a pair of fibers. Fiber is usually available from national carriers or LECs in either lit or dark form. For the purpose of this article, lit fiber is connected to a provider's network and has a signal that is generated by the provider's equipment. Dark fiber connects nodes without attaching to the provider's network. If lit fiber is installed, your choice of equipment will be limited. Usually, the provider will supply the equipment or at least offer a list of devices you can use.

Although SONET is a standard, vendors use a few bytes as they please. Most vendors, however, maintain code that will allow interoperability between their equipment and someone else's. Using lit fiber lets you move voice and data over the provider's network to PSTN or Internet services.

Dark fiber has the advantage of being yours to manipulate, within reason. You can place any brand equipment on the line at possibly any OC speed, as long as no repeaters are on the line. Repeaters placed on the line by the carrier or LEC will be designed for whatever data rate you specify but won't be able to repeat the data on the line if you begin sending data at a higher rate. Dark fiber can be installed as point-to-point connections between buildings in a campus environment or between offices within the same city.

Building a Network

SONET networks can be built in one of three fashions: linear, ring or a combination of the two. Linear networks are just as they sound: SONET switches are connected in a linear fashion with two end points and a number of switches in between. The best example of a linear network is a 10BASE-2 Ethernet network. Ring networks connect SONET switches in a round-robin fashion similar to a token-ring network.

Information can travel over two types of fiber: single mode or multimode. Multimode fiber has a larger diameter and uses infrared light (or diodes) at the transmitting end. Because of the infrared signal's wavelength, it can travel only less than a mile before it needs to be regenerated. It is therefore used primarily in LANs or short-hop campus connections. If your data needs to travel a longer distance, then single-mode fiber is the way to go. The fiber is thinner and more fragile than multimode, so it should be handled carefully.

In a simple SONET linear network, PTE (path-terminating equipment) sits at each end. This equipment takes subrate signals and multiplexes them into a SONET frame. Between the PTE devices may be several LTE (line-terminating equipment) devices. An LTE is an ADM (add/drop multiplexer); instead of demultiplexing the entire signal, as the PTE does, it pulls out only the subrate services that it needs and inserts different signals down the line. If your network is long enough, STE (section-terminating equipment) will be in the fiber somewhere. These repeaters or regenerators take the incoming signal from one side and rebroadcast it out the other side. Placement of STE in the network depends on the strength of the signal being transmitted down the fiber.

Single-mode fiber can have three or more strengths of lasers broadcasting the signal: LH (long haul), MH (medium haul) or SH (short haul). LH is the most powerful in this example and lets a signal travel approximately 90 miles before regeneration. MH has a maximum transmission distance of approximately 15 miles to 25 miles, and SH is rated for 1 mile to 2 miles. Because the lasers' strengths are tuned to the distances they need to travel, you should make sure your equipment matches your distance needs. You would burn out the receivers on both ends if you connected two single-mode LH switches with only 10 feet of fiber.

Linear SONET networks are the easiest to design and install. They don't offer the redundancy available with ring networks but are good if point-to-point, noncritical connections are needed. Two fibers are typically used--a transmit and receive--at the end points (PTE). By comparison, ADMs (LTEs) in the network will have four fibers: one transmit and receive pair from both the upstream and downstream. Although ring networks also use four fibers (one pair each from the upstream and downstream), they should never be called "transmit" and "receive." Because the information travels in a circle, a working fiber and a backup or protection fiber are connected to the upstream and downstream switches. Ring networks require two fibers for redundancy; with only one fiber all data transmission would cease if the fiber were cut.

Ring Around the Rosy

If you're connecting several offices in a city or MAN (metropolitan area network) and need redundancy for failover, consider a ring topology. SONET rings can be either unidirectional or bidirectional. Each has advantages for particular situations. Unidirectional rings use only one fiber at a time--the working fiber--and transmit in one direction only. In "Traffic Direction in a Simple SONET Ring," below, a signal from A to B would travel on the working fiber from A to B. For B to send something to A, the signal would travel from B to C to D to A on the working fiber. If a unidirectional ring fails, it will switch transmission from the working fiber to the protection fiber. The protection fiber travels in the opposite direction from the working fiber, so transmission from A to B would be A to D to C to B.

If both fibers are cut, the equipment will switch to bidirectional mode. This is called a UPSR (Unidirectional Path Switched Ring). Even though the same amount of fiber can be used, bidirectional rings differ from unidirectional rings because they can use both fibers at the same time and can transmit in both directions. In the "Traffic Direction" diagram, a bidirectional ring would transmit from A to B clockwise on the working fiber, and from B to A counter-clockwise on the protection fiber.

Bidirectional rings of four fibers (two active, two protection) use a system called span switching. Span switching lets the ring continue functioning by not only switching from the working fibers to the protection fibers, but by allowing for complete failover by transferring from the pair of working/protection fibers that are experiencing a failure to a complete second pair of working/protection fibers. In "Span-Switching SONET Ring," at right, if a failure occurred on either the working fiber or both fibers of span 1 between switches A and B, then A and B would begin talking to each other on span 2. Span switching allows the best redundancy but has the highest cost.

APS to the Rescue

Just choosing a ring versus a linear network is not enough to ensure failover protection. The SONET switch provides extra help by managing redundancy with APS (Automatic Protection Switching). APS offers three types of protection for the data on a fiber: 1+1 (one to one), 1:1 (one for one) and 1:n (one for n).

1+1 provides the best redundancy by simultaneously transmitting on the working fiber and the protection fiber. Data transmissions are sent in one direction on the working fiber and in the opposite direction on the protection fiber. Such redundancy provides immediate backup to all data transmitted because at least one signal will get to the destination switch on the working fiber or the protection fiber. Because the switch has two sources for the data (upstream and downstream), it should receive at least one, which eliminates the wait to switch to the protection fiber in case of an outage on the working fiber. The data flow continues without interruption or loss by using the data on the protection fiber automatically. 1+1 is the best solution for mission-critical data but is also the most expensive because every working fiber requires a protection fiber.

1:1 protection is less expensive than 1+1, as it uses the protection fiber as a backup only; that fiber is either idle or carrying only low-priority data from switch to switch. Since full traffic is not normally transmitted on the fiber, and it requires no network resources, most carriers will discount the protection fiber. In the event of a working-fiber failure, there will be a pause (usually no more than 20 ms) while the switches move data from the working fiber to the protection fiber--thereafter known as the working fiber.

1:n protection is the least expensive APS method. It uses only one fiber as a protection fiber for n fibers between switches. If a working fiber fails, the data is placed on the protection fiber. If more than one fiber fails simultaneously, the switch will place the highest-priority fiber's traffic on the protection fiber. If two or more equal-priority fibers fail at the same time, the switch will place the traffic from the fiber with the lowest port number on the protection fiber. 1:n is used when multiple fibers carrying different data streams from the same switch cabinet are transmitting to the next node.

While you may be inclined to incorporate rings into your entire worldwide network, they can be cost prohibitive outside of the MAN. When working with cross-country or cross-continent SONET networks, it is best to build interconnected rings. By creating multiple MANs, each as a ring network with point-to-point connections between them, large, cost-effective networks can be built and expanded by simply adding another ring to the network. "Interconnecting Campuses via SONET," above, shows a nationwide network with local rings in Dallas, Los Angeles and New York, and a single node in San Francisco. This setup controls costs by running a ring only in the MAN. It also creates failover if one intercity link fails. If calls from the PSTN to the support center in Dallas (B1) needed to be routed to San Francisco (D1), they could be routed in one of two ways: through the ring in New York (B1 to B2 to A4 to A5 to A1 to D1) or through the ring in Los Angeles (B1 to B2 to B3 to C2 to C3 to C4 to C1 to D1). Creating two paths to each ring is called Drop and Continue, and is used to make connections between nested rings (ring within ring) by forming multiple connection points.

No matter what type or size network you build, keeping all the data synchronized is vital. The term SONET starts with synchronous; however, SONET should really be considered plesiochronous--that is, almost synchronous. SONET floats all data from the DS-1 level up within an SPE (Synchronous Payload Envelope). (For a detailed look at how this works, see "Shedding Light on SONET"). This floating allows different timing to be used for each subrate piece of data. In larger networks, such as the one shown in the diagram above, this floating becomes even more important to the task of placing data from each city on the network without having to match timing perfectly.

Although SONET employs intelligence in its framing, a timing source is still required. Because of the speeds and data-transmission rates, this clock needs to be fairly accurate. SONET switches require at least a Stratum 3 clock that traces directly back to a PRS (Primary Reference Source) Stratum 1 clock. Stratum 1 clocks have an accuracy of .001 ppm (part per million), which is less than one-second deviation in 31.7 years, while a Stratum 3 is 4.7 ppm. If you are building your SONET network attached to a carrier, you should try to trace back to the carrier's Stratum 1 clock, as such equipment is very expensive. If you are using dark fiber, a Stratum 3 clock can save you money while still providing some accuracy. SONET switches are capable of timing off a loop clock source. Because many SONET and ATM devices have built-in Stratum 3 clocks, you can choose one to be your clock source. Bits 5 through 8 of LOH (line overhead) Byte S1 let switches on the network know what quality of sync is available on the loop (see "Timing Signal Quality," below).

Danger Will Robinson!

Once your network is complete, you still have to keep it running. SONET equipment can monitor several aspects of a network's health, so it is important to be aware of just what those red lights mean. Most SONET equipment can watch for three types of failures: LOS (loss of signal), LOF (loss of frame) and LOP (loss of pointer). The least severe failure, LOP, occurs when the equipment on the line can no longer correctly determine where the payload resides within a SONET frame. LOF occurs when the A1 and A2 framing bytes (1111 0110 0010 1000) cannot be found within the data stream or are found at intervals not associated with the expected frames. LOS is simply no signal found on the line.

PTE and LTE devices can recognize all three conditions, while STE devices (which don't care about the payload) can determine only LOS and LOF. When an alarm condition has been met, the upstream equipment will send an AIS (alarm indication signal, also known as "all ones") to the downstream equipment, which will generate an RDI (remote defect indication) signal toward the upstream. The equipment will also begin APS and/or notify network operations for repair.

Network notification of health was built into the SONET standard as a means to centralize operations. The SONET frame can carry OAM&P (operations, administration, maintenance and provisioning) information to facilitate network management. This is transported within the DCC (data communications channel) bytes of the line and section overheads and is used by an operations system to report and maintain the network's health as monitored from a network operations center. Traditional network management techniques are still employed.

In addition to basic lit-fiber services, we asked the vendors whether they provide any sort of managed network services over their SONET networks. To our surprise, many vendors actually offer data-networking services beyond the lit fiber. However, most of these services are negotiated on a per-customer basis, and pricing varies widely depending on which services you want the carrier to manage. The national carriers offered the most complete managed-service options. Most notably, MCI WorldCom's plan manages everything from the SONET fiber all the way up to your Internet-connected servers.

We did not award an Editor's Choice because there's so little local competition. However, AT&T showed that it is the most well-prepared and most eager to address this market, judging by the thoroughness of its response and its ability to address every one of our questions quickly. Your experience may vary, but no other company impressed us with its knowledge of the SONET market the way AT&T did.

AT&T Corp.
AT&T provided us with extensive information regarding pricing and network services on its global SONET network. In dealing with all the local and national carriers, we found it eminently clear that AT&T has one of the best technical sales teams out there. The company provided us with exact quotes for local and nationwide service, and left no stone unturned. In contrast with other carriers, both local and national, AT&T's data-services staff members were fast and efficient, and understood their network very well.

AT&T offers service in local, regional, national and international markets. The carrier offers lit SONET point-to-point services between two states at speeds up to OC-192 (10 Gbps); OC-48 and OC-192 contracts are negotiated only on an individual basis. AT&T also provides metropolitan area SONET rings in all 50 states and internationally at speeds of OC-3, OC-12 and OC-48 (155.52 Mbps, 622.08 Mbps and 2.488 Gbps, respectively). AT&T offers linear point-to-point connections, as well as unidirectional path-switched ring and bidirectional line-switched ring service at the metropolitan level.

AT&T gave us pricing information for both local and national service. For local service, one-time provisioning costs ranged from no charge in Washington to $390 per node in Chicago for OC-3 service. That figure soared to $3,155 per node for OC-48 service. Monthly charges for OC-3 service in Chicago were $12,340, while they were $20,771 in Los Angeles. OC-12 charges were more than double in Chicago and Washington but only 13 percent more in Los Angeles. OC-48 SONET ring charges ranged from $39,800 to $87,986 monthly, depending on the city of deployment.

In examining the responses from the national carriers, we quickly realized the cost of doing business at 622 Mbps on a private line--too much even for our widget juggernaut, e-Widgets. A point-to-point SONET connection between Los Angeles and Washington (2,400 miles), for example, will cost you a hefty $3.4 million per month. Building a three-point, two-route OC-12 network using point-to-point connections between Washington, Los Angeles and Chicago adds up to $7.4 million monthly. All AT&T's long-haul, private-line fiber is priced per mile, so shorter distances will carry lower charges.

This is where the consolidation of voice and data services really starts to come into play. With SONET, you can easily carve out bandwidth for all the DS-1s and DS-3s you need to run your routers, PBXes, VPN devices and anything else you might want to tie across this 622 Mbps, coast-to-coast network. AT&T does not offer OC-3 service between the selected cities.

AT&T offers managed service up to the multiplexor and provides managed-data services on a custom basis. The company's Accu-Ring service is a managed ring service that allows advanced customers to manage path routing and bandwidth allocation from their own premises via a GUI tool. These changes can take place in "near real time," according to AT&T officials.

AT&T's outlook for the next 12 to 18 months includes rolling out OC-192 services to 30 major cities as well as plans for optical switching using DWDM (dense wave-division multiplexing). The carrier is also aggressively partnering with smaller companies to expand their SONET services nationwide, with plans to roll out more than 13,000 miles of additional high-capacity fiber by the end of 2001.

AT&T Corp., (800) 326-5583, (212) 387-5400. www.att.com or www.att.com/data/contactus/index.html

Bell Atlantic Corp.
Bell Atlantic did not complete our survey. However, we were able to glean the following information from the company's Web site. Bell Atlantic offers SONET from OC-3 to OC-48 in Delaware, the District of Columbia, Maryland, New Jersey, Pennsylvania, Virginia and West Virginia. Plans are under way to make it available soon in Maine, Massachusetts, New Hampshire, New York, Rhode Island and Vermont. We tried three times to call the carrier's customer-service division and obtain information about its SONET services; none of the technicians who spoke with us could help, however, and two didn't know what SONET services were. We were finally informed that SONET services are sold only by large-accounts salespeople and that we should contact our local sales representative for a quote. The press relations team at Bell Atlantic ignored our repeated requests for information about its services.

Bell Atlantic Corp., (800) 846-1200, Ext. 1200. www.bellatlantic.com or www.bellatlantic.com/about/contact_email.htm

BellSouth
BellSouth's footprint covers Alabama, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina and Tennessee. The company provides OC-3, OC-12 and OC-48 service today, with OC-192 service planned for the future. BellSouth can provision service for linear point-to-point connections, in a unidirectional path-switched ring or in a bidirectional line-switched ring. Dark fiber is also available on a per-mile basis.

Regardless of the optical rate you choose, a lit-fiber configuration from BellSouth has a $1,020 nonrecurring provisioning cost. OC-3 service prices out at $5,675 per month for a linear configuration, OC-12 costs $10,075 monthly and OC-48 goes for $20,875. Dark fiber can also be provisioned for $241 per fiber per route mile, but that price excludes special construction costs.

BellSouth offers managed service at the SONET and data layers only on a custom basis--that is, for large customers. BellSouth's specific data services include frame relay and ATM service over the SONET backbone. BellSouth is planning to provide OC-192 capability to its backbone in the next 12 to 18 months and will also add support for asymmetrical interfaces.

BellSouth Corp., (404) 471-0568; fax (404) 471-0959. www.bellsouth.com or kathy_boughey@bbs.bellsouth.com

MCI WorldCom
Where AT&T highlights its extensive national markets and high-speed SONET services, MCI WorldCom touts its joint (MCI + WorldCom) national and international fiber resources. The company boasts coverage of 89 major metropolitan areas in the United States and a 40-Gbps transatlantic connection to 44 European and East Pacific/Asian markets. MCI WorldCom provided detailed maps of its coverage areas. In addition to offering its nationwide backbone, the company has no qualms about working with local and regional carriers to bring customers the exact type of service they need. If MCI WorldCom can't provide SONET service on its own fibers, the company will work with the appropriate regional carrier to get you the connectivity you want.

The biggest advantage we saw in MCI WorldCom's response was the ability to add incremental bandwidth as an enterprise's network requirements increase. The national carrier offers the full range of standard OC services, from OC-3 all the way up to OC-192. The carrier also uses "volume options" such as VO-6 or VO-24 (concatenated OC-3s and OC-12s) to provide incremental speeds of 155.52 Mbps, 311.04 Mbps, 622.08 Mbps, 1.244 Gbps and 2.488 Gbps.

Customer provisioning options are linear or unidirectional path-switched ring. The MCI WorldCom backbone is built on a bidirectional line-switched ring for ultra-high reliability in the network core.

Installation costs for any volume of service are $1,250 (to terminate the SONET service into an add/drop multiplexor), plus multiplexor interface charges, which range from $25 to $100 per interface, for the customer premise side.

Monthly costs for OC-3 service start at $13,500 in the configuration we requested. OC-12 service starts at $22,800 and OC-48 service at $53,100 monthly. VO-6 and VO-24 pricing falls in at $18,225 and $30,780, respectively. VO-96 service starts at $71,685.

MCI WorldCom's base prices do not include the monthly cost of customer-side multiplexor interfaces to use the bandwidth. MCI WorldCom's prices are comparable with AT&T's city-specific prices. However, MCI WorldCom refused to provide us with coast-to-coast pricing information. We suspect the company was bashful to disclose its private-line pricing structure.

While long-distance carriers AT&T and Sprint spent little time telling us about their managed-service offerings, MCI WorldCom surprised us with complete managed-SONET-service and managed-data- service options for our proposed network. The MCI WorldCom crew offers a complete range of managed-data services and can manage any part of the network--from just the SONET service to the enterprise Web server.

The power of the Uunet-MCI-WorldCom merger really shows here, with a complete data-application-LAN-WAN solution that can be managed entirely by the company's support staff. Whether you choose this level of integration or just SONET device management, these types of contracts are all negotiated on a per-incident basis.

MCI WorldCom's long-term growth plan is one of the strongest presented. The carrier provides OC-192 capacity today, using 16- and 32-wavelength DWDM equipment in its core backbone, and is targeting 60 to 160 wavelengths in the near future. The carrier also successfully tested a 1-terabit network between Dallas and Longview, Texas--a 150-mile fiber run with 100 DWDM channels over a single fiber. Likewise, the company's local market penetration is one of the strongest--neck and neck with AT&T--covering 74 U.S. cities (42 of the 50 largest in the country) and 89 metropolitan areas. In addition, MCI WorldCom has fiber resources that provide coverage to more than 60 percent of all businesses in the United States.

MCI WorldCom, (888) 624-9266, (601) 360-8600. www.wcom.com or sales@wcom.com

SBC Communications
SBC Communications is "undoing" the Ma Bell breakup of the '80s. The parent company of Southwestern Bell, this regional Bell has also quietly swallowed up both Pacific Telesis (Pacific Bell's parent company) and Ameritech, and offers SONET services in 12 states (Arkansas, California, Illinois, Indiana, Kansas, Michigan, Missouri, Ohio, Oklahoma, Nevada, Wisconsin and Texas) and 23 countries.

Because the regional Bells were allowed to provide only non-long-distance, or intra-LATA (local access transport area), services until the mid-1990s, SBC provides only local MAN connectivity. That is, SBC can provide SONET services for offices in Wisconsin and California but can't connect the two. However, the company is planning to expand to national and international markets in the coming year. SBC used the Ameritech pricing model when quoting specifics for SONET services in all 12 states. Pricing may vary in other coverage areas, but the company was unable to be more specific on the Pacific Bell and Southwestern Bell markets.

SBC's offerings include bare lit fiber, as well as a partially managed service that includes proactive connectivity and Web site performance monitoring. In terms of bandwidth, SBC/Ameritech offers OC-3, OC-12 and OC-48 services, as well as aggregated multiple OC-3/OC-12 service, which allows you to have incremental bandwidth between OC-3 and OC-12, as well as between OC-12 and OC-48 service speeds. OC-48c access will be available when the SBC/Ameritech OC-192 network comes on line. That network is in development now and will be available within 12 to 18 months.

The SBC/Ameritech offering is available in a linear point-to-point configuration with 1+1 protection and diversity options, or as a unidirectional path-switched ring. Bidirectional line-switched ring support is under development but is not currently offered.

SBC/Ameritech has one of the lowest installation costs. Regardless of speed, initial SONET provisioning costs $650 per ring service. This is a nonrecurring charge. For the ring configuration we created, with three nodes and a total distance of six miles, SBC/Ameritech quoted a monthly price of $6,345 for OC-3 service, $12,300 for OC-12 service and $25,600 for OC-48 service. SBC requires a 36- or 60-month SONET service contract; rates for our company are for a 60-month contract.

SBC/Ameritech was one of the few vendors to articulate a managed-service offering, which includes 24x7 monitoring and a dedicated technician to provide service on a day-to-day or an as-needed basis. Like most vendors, SBC also will customize a managed-service offering for large customers. SBC didn't offer any information on a managed-data service--only on managed private-line SONET service.

In the future, SBC plans to add online bandwidth ordering, trouble ticketing, capacity management and real-time performance reporting. OC-192 backbone service and a unified SONET offering (complete with unified single-vendor SONET backbone gear for SBC's entire footprint) are major priorities.

SBC Communications, (800) 622-6416; fax (847) 715-5980. www.sbc.com or patrick.smith@ameritech.com

Sprint
Like AT&T and MCI WorldCom, Sprint has a national footprint and offers SONET services in the top 40 major metropolitan areas across the United States. Sprint delivers a number of its services via CLEC (competitive local exchange carrier) and access arrangements in areas where it does not provide direct fiber connectivity to its backbone. The carrier provides a nationwide, bidirectional line-switched SONET backbone that consists of more than 200 rings and 300 points of presence in the United States.

Sprint offers local access at speeds of OC-3, OC-12 and OC-48. Sprint did not provide us with specific local-access charges, saying those costs vary by thousands of dollars depending on the location of the ring and the customer premise. Sprint representatives told us the company's strategy is always to be price competitive in a given market.

At the national level, we applaud Sprint for its 100 percent bidirectional line-switched SONET backbone. Though you'll benefit from this network as a consumer, you'll have a hard time getting plain old lit fiber. Sprint doesn't have a pricing structure for private-line services; instead, it offers only switched data services, such as ATM and frame relay. Sprint offered us an OC-12 ATM configuration on a ring between Los Angeles, Washington and Chicago. This service costs $20,000 per node per month ($60,000 total), plus $9,500 per UBR (unspecified bit rate) PVC (Permanent Virtual Circuit) per node per month. A nonrecurring $4,200 fee applied at each node. Local access charges in each city were estimated between $10,000 and $15,000; these are the last-mile charges that we asked the vendor to waive, but they are provided here to give you a baseline for reference.

Sprint's Managed Services comprises an integrated suite of consulting, implementation and operations services. These services support a variety of customer premises' network equipment--routers, hubs, ATM devices and LAN switches--as well as managed security, managed enterprise servers and applications, and managed desktops and applications. The services include state-of-the-art remote management capabilities as well as proactive monitoring and upgrade of all network components.

Sprint, (800) 370-6105, (972) 405-5000; fax (972) 405-5055. www.sprintbiz.com

U S West
The U S West footprint covers 14 states: Arizona, Colorado, Idaho, Iowa, Minnesota, Montana, Nebraska, New Mexico, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming. Offerings are regional (within the service footprint)--meaning U S West can hook up metropolitan areas but can't necessarily cross state lines--and include lit-fiber service, and managed private-line and data services.

U S West offers service at OC-3, OC-12 and OC-48 speeds; OC-192 is on the horizon. It also offers an incremental OC-24 speed. Configuration options include linear point-to-point configurations, as well as unidirectional path-switched ring topologies and a unique linear redundant option, in which multiple linear connections are offered at an intermediate price (between linear- and path-switched ring), with automatic failure recovery.

U S West charges $2,910 for provisioning and installation--but only for a ring configuration. Thus, while the monthly price the company quoted is higher than that asked by SBC and BellSouth, it includes SONET service to your doorstep. OC-3 services cost $9,300 per month in the linear configuration, or $17,170 in the path-switched ring configuration. OC-12 services are $21,486 and $35,220 per month, and OC-48 service was quoted at $67,944 and $55,580 monthly (yes, ring configuration is less expensive than linear at OC-48 speeds).

U S West provides both managed- ring and managed-data services. Basic managed service includes monitoring up to and including the multiplexing equipment on the premises. An enhanced data service is also available as part of a package; however, U S West didn't offer any additional information on its managed service offering.

U S West's plans include OC-192 service to customers' premises, as well as a slew of data services, such as 10- and 100-Mbps Ethernet connections to the SONET ring, packet over SONET and ATM over SONET.

U S West, (800) 304-3910, (303) 965-5425. www.uswest.com or www.uswest.com/products/data/sonet/contact.html

Send your comments on this article to Joel Conover at jconover@nwc.com.

Executive Summary SONET Services Building a nationwide SONET network is beyond the realm of possibility for most enterprises. But provisioning one is not. To do so, it helps to know the basics--beyond the fact that SONET offers exceptionally high bandwidth and can carry many types of information over a single strand of fiber. You have a choice of three network styles: linear, ring or a combination. Typically, a linear network is easiest to design and install, and is most appropriate for point-to-point, noncritical connections. SONET rings, meanwhile, can connect several offices in a city or metropolitan area network. Unless you're building office campuses from the ground up, chances are good that you'll be getting your SONET services from local or national telecommunication service providers that have the infrastructure in place. We surveyed regional carriers and national carriers to find out just what it takes to build a nationwide SONET network. National carriers AT&T, MCI WorldCom and Sprint compete fiercely for your coast-to-coast and international business, while local carriers provide last-mile connectivity with pricing dictated largely by local tariff structuring. While your exact costs will vary based on the proximity of your sites to the nearest SONET ring, we provide an apples-to-apples comparison of the SONET services available nationwide.