Feature Story
February 2, 1998
The changeling
Open programmable switches can help a wide range of emerging carriers--including CLECs, PCS operators and international callback providers
MONICA PACKI
Bob Dylan may not have been thinking telephony when he said, "The times they are a-changin'." But like our times, industries change and evolve, influenced by new ideas and advancing technology.Government regulation plays a significant role in the way industries change. Sometimes even the slightest change in legislation can create new markets or significantly influence an industry.
In the telecommunications market particularly, global deregulation has led to shifts in network infrastructure. As a result, a huge market for open programmable switching platforms has emerged, and the influence of this product is reflected in new and existing networks worldwide.
Traditional switches are closed to third-party application developers. In other words, only the manufacturer can offer new services and features on these platforms. Because of this, closed systems have higher feature costs and long lead times for new services.
Custom or market-specific features are not cost-effective for these vendors to develop because they must sell every feature to the mass market. However, demand for niche applications and rapid time to market have been key drivers for open switches.
Open programmable platforms address the limitations of closed switches by allowing manufacturers and carriers to create innovative services and products that can be quickly and easily deployed worldwide. Competition among vendors has driven down prices and increased the functionality of open switch-based solutions, benefiting carriers and consumers.
To clearly understand the role of open switches in next generation networks, carriers will want to consider traditional architecture, network evolution, current capabilities and implications for future networks (Figure 1).
Born of competition
Open switches first entered the market in the early 1980s as adjuncts that controlled message distribution and management for local exchange carriers. The 1984 breakup of the AT&T monopoly opened competition in the long-distance market.
To differentiate themselves, long-distance companies rapidly began to deploy enhanced services. Long waits for these new services on closed switches fueled the demand for open platforms, which provided rapid time-to-market and low cost for new services.
The telecom market was further deregulated in 1988 when a petition from the Bell companies was approved, opening e-mail and voice storage markets. The enhanced service market opened in the 1990s, allowing third-party companies to access public networks.
These regulatory changes let Independent telcos enter more markets and granted them greater access to public network information. As a result, the array of services available on open switches and the number of application developers in the market began to increase.
International markets also started to capitalize on these products as some open switch vendors extended the programmability of their products to include on-demand creation of E-1 signaling variants.
Although the majority of applications provided enhanced services, the uses for open platforms expanded in the mid-1990s to include deployment in core network switching roles. For example, PCS and wireless local loop (WLL) network operators started deploying networks without a guaranteed customer base and while paying high start-up costs.
These carriers had to reduce expenditures as much as possible, while still providing a wide variety of enhanced services to compete with incumbent wireless carriers. Traditional switch vendors did not have acceptable low-cost solutions for these new "zero" customer networks.
The scalability, performance and low cost of open platforms made them ideal for wireless applications. As a result, wireless carriers began incorporating programmable switches into their networks for use as mobile switching centers and base station controllers.
In fact, the powerful capabilities of some open platforms provided infrastructure vendors such as Qualcomm the ability to put both mobile switching centers and base station controller functions on one scalable open platform. This enabled vendors to reduce infrastructure cost, easing the financial burdens on new carriers.
The Telecommunications Act of 1996 is having an even greater catalytic affect on the domestic open switch market. Although the details are still in litigation, this act significantly deregulated the telecom industry, allowing new competitors to enter local and long-distance markets.
Some of these new carriers started by leasing infrastructure from incumbent carriers, but many have focused on establishing new switch-based networks to minimize long-term costs. New entrants that are deploying their own infrastructure need scalability, flexibility and low cost to remain competitive.
These conditions have inspired more carriers to deploy network solutions based entirely on open platforms. The expanding array of open platform-based systems is being increasingly accepted in networks worldwide as governments continue to encourage competition.
Programmable switches operate seamlessly within traditional network infrastructure. This complementary relationship has helped programmable switches gain a foothold in the market and increase overall network functionality.
However, deregulation and the rapid growth of programmable switching has begun to change the overall look of telecom networks. In fact, even traditional switch vendors have been convinced to produce more open scalable network infrastructure.
A class structure
In the past, the North American market was designed as one large network, owned and operated by AT&T. The divestiture in 1984 changed this configuration, putting Bell regional holding companies in charge of seven regional networks.
But since the telecom act was passed, this rigid framework has lost its boundaries. Now competitors are allowed in virtually all telecom markets and across all regions. This shift from one, to few, to many networks has significantly affected the original telecom architecture.
North American telecom networks were designed to support a hierarchical switch distribution, often referred to as "class" switches numbered one through five. A Class 5 switch serviced the local area or end office, Classes 4 through 2 accessed longer distances, and Class 1 was international. This architecture was centralized, with the originating call passing through a limited number of switches to reach its destination, ensuring that regional calls were not switched across country.
Modern networks are losing this centralized class architecture. As the network continues to diversify, switch vendors are combining switch functions and losing class distinctions between switches.
The benefits and flexibility of open switches further encourage this change. Programmable platforms easily function as any one or a combination of class switches, eliminating the need for several class switches and greatly reducing start-up costs for new carriers. Additionally, networks based on open platforms gain the significant benefits brought to bear from a large development community.
This change in switch architecture is bringing network intelligence closer to the user, much like the evolution of the computer industry.
That industry started with dumb terminals connected to large, single-purpose mainframes provided by one vendor. As computers became more open, more functionality moved to the terminal and applications increased because of the number of manufacturers.
Telecom networks are evolving in the same way, moving from closed switches provided by one vendor to open switches with many developers providing functionality.
Current capabilities
Open switches entered the market as the enabling technology for enhanced service platforms, and they still are widely used in this market. In fact, their value is increasing as the competitive environment has carriers seeking differentiation and increased revenue through added features.
Long-distance and wireless networks also are leveraging enhanced services to increase revenue from minutes of use. Services such as one-number, voice mail and debit cards are ideally suited to programmable platforms because they can be deployed without an expensive Advanced Intelligent Network (Figure 2). In addition, implementing adjunct systems provides a way to prototype and test new services with minimal capital commitments and risk.
Programmable switches, however, play a role in AIN implementation. AIN network architecture was designed while the Bell companies provided service, which was still largely centralized. Implementing AIN also was more expensive, rigid and arduous than originally expected.
Although still a viable option for RHCs and large carriers, AIN in its original design is not ideally suited for most new carriers because of the high initial investment required. Yet emerging networks still need AIN features to remain competitive with incumbent providers.
As a result, AIN features are being developed on programmable platforms that provide advanced functionality at a much lower total cost. Often called service nodes, these open platforms are playing a significant role in helping carriers compete. In addition, larger networks also are capitalizing on the benefits of open platform-based service nodes because of their flexibility and time-to-market advantages.
Programmable switches also are making an impact on the network infrastructure market. Wireless market needs for scalability, low cost and capacity have fueled a heavy demand for open platforms.
Besides their functionality as a mobile switching center, base station controller or a combination of both, open platforms provide even greater benefits to wireless networks. For example, some vendors offer sub-rate switching capabilities that allow the platform to operate as a true bit switch.
Because of limited amounts of valuable spectrum, most air interfaces use anywhere from 8 to 32 kb/s rates for air interface transmission. Typically, the call is converted through vocoding to a 64 kb/s rate to enable switching, then vocoded back to its original rate of 8 to 32 kb/s.
Sub-rate capabilities in some open platforms allow air-to-air calls to be switched at their original sub-rate. As a result, up to eight calls can be carried and switched on one DS-0 (64 kb/s).
With many wireless markets spread out geographically, the benefits of sub-rate switching increase. Calls connecting between mobile switching centers in different markets can still be switched at sub-rates, providing much greater trunking efficiency and further reducing the need for leased lines. These benefits in trunking efficiency, port capacity and minimized leased lines can mean significant revenue advantages for carriers.
Wireline acceptance of open platforms in infrastructure is beginning to parallel growth in wireless networks. Open platforms were first incorporated into landline network infrastructure as tandem switches to provide interLATA services.
Virtual private network, international gateway and international callback services on open switches also have increased confidence in open platform products as wireline infrastructure. Now some vendors are using programmable switches for end office or Class 5 switching infrastructure, bringing open platform services even closer to the end user.
As more products are developed on open platforms, carriers are finding increasingly innovative ways of maximizing switch resources. For example, the programming flexibility of open switches facilitated the development of solutions that support both WLL and wireline service.
Opportunities for carriers typically exist for both services because WLL is often deployed in regions with underdeveloped public networks. Carriers deploying WLL/
wireline switches are improving the public network while reducing network costs and increasing return on investment.What's next?
As the ideas and uses for programmable switches expand, so does the potential for future networks. In general, greater functionality and better programming tools are being offered to facilitate development of open platform products.
For example, open platforms themselves are gaining more intelligence. More basic call processing functions are residing on the switch, allowing manufacturers to focus on value-added components of their applications. This shift is being accomplished without diminishing the flexibility or programmability of the total solution.
Another effect on future networks will be the ability to bring media resources directly onto switching backplanes. Both resources and the switch will function as one open unit within a "software envelope."
This will provide transparent switch functionality seamlessly operating with applications residing on third-party voice and media processing boards. Integrating these components not only simplifies application development and deployment, but it also eliminates costly T-1 (1.5 Mb/s) lines between the switch and integrated resources.
The integration of multiple off-the-shelf applications also is becoming easier. Previously, a single application developer had to provide multiple applications because of feature interaction issues.
In the near future, multiapplication environments will enable the carrier to choose different application vendors and easily integrate them on the same open switching fabric. Carriers will then be able to pick and choose best-in-class applications to create customized service sets based on off-the-shelf software.
Some open switching systems currently offer capacities of up to 30,000 ports. Expandability above 30,000 ports soon will be available, allowing developers to create new products that scale up to and beyond many closed switches.
This will encourage even wider deployment of open platforms into both wireless and wireline networks. Also, this added scalability will enable carriers to accommodate rapid network growth, while continuing to leverage the advantages of open switching architecture.
Looking ahead, emerging applications may benefit from features being offered on programmable platforms.
Wireless data, for example, has been slow to gain market acceptance. However, open switches with sub-rate controllers may be invaluable for some proposed standards.
For instance, the data portion of the CDMA IS-95B revised standard scheduled for approval in April will use from one to eight increments of 8 kb/s to provide data rates up to 64 kb/s. Sub-rate controllers could provide the ability to combine and disassemble these channels.
The new data service logic for this proposed standard resides in the base station controller. Therefore, open platform base station controllers with a sub-rate card for voice switching should quickly upgrade via new software to add data functionality.
Because many wireless networks already have programmable infrastructure, upgrades would be minimized, encouraging more carriers to offer data service. In turn, the deployment of open switches in wireless voice networks may equate to growth in the wireless data market.
The evolution of telecom networks from closed, centralized switches to open, distributed, multifunctional platforms already has significantly affected the industry. Deregulation, competition and an expanding number of carriers will continue to fragment the market, forcing carriers to use technology that offers competitive advantages in cost, time to market and feature flexibility.
Although even short-term predictions are hard to make, one thing is clear: "the times they are a-changin'." Open programmable switches are both driving and being driven by these changes.
Monica Packi is Wireless Industry Specialist for Excel Switching Corp., Hyannis, Mass.www.internettelephony.com
Telephony February 2
©1998 Intertec Publishing Corp., a Primedia company
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