A New Vision of the Network of the Future

Federal regulators have paved the way for the incumbent local exchange carriers to provide what the telecom act calls "advanced services," meaning high-speed digital access. The scope of the advanced-services infrastructure is enormous, encompassing the entire regional Bell operating company network. The impact on users could be enormous as well.

The new broadband access networks differ from the current networks in that they will involve smart, fiber-based remote devices that operate between the user premises and the carrier central office. These devices will be capable of supporting multiple service relationships per customer -- voice calls, data services, Internet and so on. In short, the network of the future will perform service-specific routing of connections. Thus, we can expect that a future network will support Internet access not via dial-up over the public switched telephone network, but by simply setting up another service connection from the customer to the point where the Internet service is offered.

This point could be called the service point of presence (SPOP). Like a long-distance carrier's point of presence, the SPOP is where the user and the service really link up. The access network acts only as a conduit to get the right information to the SPOP. At the SPOP, service features can be added by interpreting the user's incoming data flow and responding. By building a network of SPOPs you can create national and international services, each supporting its own user community via local access connections.

The impact of the SPOP on the networking market will be profound. For example, consider the so-called Internet offload problem. This occurs because with today's dial-up ISPs, we use a voice service to make an Internet access connection. In the network of the future, the Internet flow from customer to ISP will never touch a voice device, so there will be no Internet traffic to offload.

The SPOP's biggest impact, however, will be on the concept of convergence.

Dense wave division multiplexing (DWDM) transport already promises to lower the cost of long-haul bits. If we imagine any service network as a network of SPOPs, it's clear that those networks can use any form of protocol they find convenient. Voice traffic can continue to use time-division multiplexing, and IP packets can be transported as IP packets.

Even at the device level, service grooming in the access network changes the whole picture. Vendors once visualized next-generation voice products as having voice-data features to handle the users' demand for multiple services. With each service flow separated at the point of customer connection and directed to its own service-supporting destination device, why should we care about integrated features in a device?

SBC Communications' Project Pronto, which promises an ATM-based access network for all SBC customers (eventually), shows how the SPOP concept works in its support for traditional voice services. Class 5 switches from Lucent or Nortel Networks, attached to the ATM access network, will receive cells created from the analog dial sequences and voices of the users. These switches will generate their own cells representing the call progress signals and voices of the other parties on the call. The existing Class 5 switches will be voice SPOPs. ISPs such as SBC's partner Prodigy will provide Internet SPOPs.

What will SPOPs look like? Chances are there will be as much diversity in SPOP architecture as in long-haul transport protocols. The only common element in SPOP architecture is the need to support the RBOC or other access networks -- meaning ATM and cable or packet interfaces.

SPOP devices also may offer better Multi-protocol Label Switching support than traditional network hardware because MPLS is a convenient way to bridge ATM, packet and optical technology with a single protocol.

For users, the SPOP architecture means that the focus of convergence will fall on the access device, an area that has been neglected in favor of faster and more glamorous core technologies, such as terabit routers or DWDM switches. It also means that a user will have an access provider that offers the last-mile infrastructure and a series of service providers whose SPOPs create the voice/data service mix the user consumes.

As all of this unfolds, it will affect everything from network management to business planning. Monitor the progress of your access carriers and access equipment vendors to be certain they're not caught unaware as these changes develop.

(Nolle is president of CIMI Corp., a technology assessment firm in Voorhees, New Jersey. He can be reached at +1-856-753-0004 or tnolle@cimicorp.com.)

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