Thanks in part to the growing number of interconnected local area networks, data traffic now makes up a significant share of the mix of signals that corporations are sending through their T-1 multiplexers. As a result, T-1 multiplexer vendors are reshaping their roles and gearing up new technologies that will help speed data across the well-traveled T-1 path.
Although voice traffic once dominated T-1 lines, data traffic now accounts for about half of the signals routed by T-1 multiplexers, according to Curtis Price, market analyst for data communications at International Data Corp., a market-research firm in Framingham, Mass.
Service carriers have helped to bring more data onto T-1 lines — by reducing public network tariffs enough to make it cost-effective to send voice traffic over public networks. With voice traffic moving off the private network, corporations have more room on their leased lines for data transmissions.
Another contributing factor is the growth of LANs and WANs, which has given corporations more data to send. “LANs,” Price said, “have hit hard. The ability to efficiently accommodate LAN traffic is fast becoming a priority for mux vendors. Basically, they are trying to become solution providers,” he said.
Shifting sales approach
Jennifer Pigg of The Yankee Group Inc. agreed. Multiplexer vendors have had to retarget their sales efforts, according to Pigg, program manager for data communications at the Boston-based market researcher. Vendors have moved their sights from the communication managers, who are well-versed in multiplexer technology, to network managers, who need help dealing with the myriad multiplexer options, she said.
“[The multiplexer vendors] are becoming more [like] network integrators. They are expected to know all the aspects of the network and are expected to advise the user on the design of networks,” Pigg said. “The mux provider is supposed to make sense [of what’s available] and what course the buyer should take.”
For example, Racal-Datacom Inc., a vendor of T-1 multiplexers in Sunrise, Fla., labels itself as a “full-service provider,” said Glen Smith, senior vice president and general manager of the company’s access products division. “Our T-1 multiplexers just form part of a broad product range,” Smith said.
And Ascom Timeplex Inc. in Woodcliff Lake, N.J., touts a similar strategy. “We want to become a strategic partner with the buyer,” said Michael Shumway, product manager for Ascom Timeplex’s line of Link multiplexers.
“We provide outsourcing. We can run your whole network for you if you choose. In terms of the product mix, we have all the products available to you and your entire network — for the LAN and the WAN. All that can be Ascom Timeplex equipment,” Shumway said.
Others are also in the LAN equipment game. General DataCom Inc. sells LAN routers, and Network Equipment Technologies Inc. offers a LAN switch through its subsidiary Adaptive Corp.
But in addition to the one-stop-shopping pitch, T-1 multiplexer vendors are plugging new capabilities and technologies for sending data more efficiently.
For example, the number of T-1 multiplexers supporting the much-higher-capacity T-3 lines is growing, according to Eugene Bronstein, a research analyst with Market Intelligence Research Co. in Mountain View, Calif. T-3 lines carry data at 44.73M bits per second, compared with T-1’s 1.544M bits per second.
“Most of what is sold today as T-1 [multiplexers], especially for networking, can also be configured as T-3. You just plug in a card,” Bronstein said. “The distinction between T-1 and T-3 [multiplexers] is going to go away.”
Bronstein said he also expects support for inverse multiplexing to grow with the popularity of applications such as video teleconferencing. With inverse multiplexing, the multiplexer breaks down wide bandwidth into smaller signals. The multiplexer then dials up as many telephone lines as it needs to transmit the signals.
Because inverse multiplexing doesn’t require leased T-1 lines, Bronstein said, “You’re only paying for the telephone-line time that you need, so it becomes a cheap way of sending wide-bandwidth applications.”
Techniques for data transmission are also evolving.
According to Price at IDC, “[Vendors] are trying to transition their platforms from a straight TDM [time-division multiplexing] architecture to a more flexible one that will accommodate both packet and circuit.”
TDM is the conventional T-1 multiplexer technique for transmitting both data and voice. The multiplexer interleaves bits of several voice or data signals one after the other and routes the combined stream over a T-1 line. A multiplexer at the receiving end reassembles the bits of signals into their original form.
TDM saves transmission time, because multiple signals don’t have to be sent out one at a time, and conserves resources, because only one channel is being used.
TDM also guarantees bandwidth, which ensures the same throughput speed for every transmission.
First among the new and supposedly improved options is frame relay, which divides data into packets or frames of varying sizes rather than interleaving bits of signals. The packets contain all necessary addressing information, so each can be sent via a different route and reassembled at the receiving end. Whenever there’s a burst of data from the network, bandwidth instantly becomes available for sending the packets.
According to Shumway at Ascom Timeplex, which offers a frame-relay product, frame-relay technology will provide a more efficient way of handling data in some applications. But, he added, frame relay is still in a testing phase, as individual companies try to determine which of their applications will benefit most from it.
Other vendors have adopted an even more tentative posture. “There’s always a possibility of adding things like frame relay,” said Jim Marsan, product manager for network access products at multiplexer vendor Newbridge Networks Inc. in Herndon, Va. “We have been looking at it and researching it, but we have not committed to it.”
Most vendors are, however, committed to providing Asynchronous Transfer Mode (ATM) technology in their multiplexers, when the final standards and service-carrier support arrives. ATM is a cell-relay and switching technique that uses fixed-sized cells for high-speed transmission of images, video and voice — as well as data. Full-blown implementation, however, is still several years away.
“The standards [for ATM] are still in the jelly stage. If you tried to take a product commercial today, you really couldn’t deliver product,” said Rick Miskiman, Newbridge’s vice president of marketing
Smith at Racal-Datacom said he doesn’t expect ATM-capable products for a few years. “In the 1995-96 time frame, you will see the evolution of ATM-based products. Maybe there will be one or two before then, but there will be a lot more after that.”
While new products and new technologies better enable T-1 multiplexers to deal with data traffic, they also represent vendors’ attempts to maintain a foothold in a somewhat saturated U.S. market, according to Pigg at The Yankee Group.
T-1 multiplexers had their heyday in the late 1980s, when corporations were first establishing private networks. With those backbones pretty much in place, the demand for T-1 multiplexers has slowed considerably. Vendors have shifted their focus to improving capabilities on the T-1 devices, introducing new products and marketing access and feeder multiplexers that work with T-1 backbones already in place.
In the late 1980s, many companies installed T-1 multiplexers as an economical means of communicating voice and data. These multiplexers now form the backbone of extensive wide area networks and communications systems.
Many buyers look forward to T-3 support, cell-relay technology and other improvements that will bring about even faster communications. Here are some of their views. — Caroline A. Duffy ” We have five full-blown node sites and six tributary sites. There are 16 T-1s on the network. We use [Cray Communications Inc.’s] DCP 9900 and 9100 [T-1 multiplexers].
“We’re a bank holding company. When we acquire a bank, we back-haul all the local data traffic from the regional node into the corporate backbone network … .
“To manage the network remotely, we take information off the system and feed it into a spreadsheet [to create] management reports. We don’t want the mainline management system to be anything but a workhorse. … I let Cray Communications take care of the backbone and provide me with the data, the information that I can use and that I can format using other systems.
“[Regarding the new technologies coming out,] our philosophy as a corporation is to follow the leading edge. We don’t want to be on the bleeding edge. We watch for products to begin to mature, and that’s when we choose to purchase. We sit down with Cray Communications’ engineering people and tell them our needs. They in turn share with us their development work. … Cray Communications has a new product coming out with frame-relay and routing functions on a common bus. We’re excited about that potential.
“We’re also looking for Cray Communications to address the need to handle increased bandwidth demands on networks as image capture becomes viable. ”
Steven Bowman, vice president of telecommunications-network services group, First Bancorp of Ohio, Akron, Ohio ” We use [Network Equipment Technologies Inc. multiplexers] to create a backbone network. It handles 90 percent of our voice and data traffic. We started with two nodes back in 1986. We’re up to 66 nodes comprising in excess of 300 T-1 lines. It’s been very cost-effective.
“Back in 1986 one of the things we were trying to do was combine all of our data to get economies of scale and fault tolerance. Back then, not many products could do both. The N.E.T. multiplexers detect faults both on the mux itself and on the T-1 links and route the traffic around those choke points.
“With fault tolerance, one of the things is to route traffic dynamically. Another is to define those parameters that determine what caused those conditions to occur. The third is to place traffic back on [the initial route] once [the problem] is repaired. [The N.E.T. multiplexers] allow flexibility in determining what traffic is to be routed and what traffic we want to pre-empt [if a problem occurs]… .
“There are many different customers out there with many different needs. Rather than force them into something that’s not appropriate to their needs, we try to accommodate them. So when packet-switching, ATM [and] frame relay become available for … uses that lend themselves to packet [technology], we will put users on. Those that don’t, we will continue to support them.
“I’d like to see the same functionality in smaller boxes [as in the larger muxes]. ”
Bill Ownby, senior analyst for network change management, AMR Corp., Fort Worth, Texas ” We have a private wide area network of 230 miles of fiber-optic cable and digital microwave that we own and maintain. We have 21 [Racal-Datacom Inc.] T-1 multiplexers, controlling in excess of 100 T-1s [and connecting] 14 different sites.
“Although we have a large fiber network, we also use telephone lines as backup, and the Omnimux 9000 allows us to reroute traffic [onto the telephone lines] if we have a fiber cut.
“[Racal-Datacom’s] network-management system fits in with all the other network-management systems we use. We use Sun [Microsystems Inc.] SPARCstations running X Window Systems and Motif. We use Racal-Datacom’s CMS 6000 (a network-management and control system) as the wide area network manager.
“On the LAN side, we have Cabletron Systems Inc.’s Spectrum [network-management software], and we have that and the 6000 co-resident in the network and operations center’s Sun workstations. I can sit down at one screen and see the WAN and LANs, and get into [the whole system].
“There are a couple of things I look forward to. [One is] a good T-3 interface into the 9000, and that’s coming. Another thing has been the capability of loading new software in without taking the network down. In the long term we want to take a strong look at [asynchronous transfer mode]. “