Among the most important issues in developing the Next Generation Network architecture, developed by the Alliance For Telecommunications Solutions, will be interfacing the new systems with other networks while figuring out the transition from legacy systems.

At the top of the to-do list is devising the interface for the growing proliferation of devices, including some of the newer Internet- and video-enabled mobile phones, pagers and wired hardware as well as other devices still under development, said Nick Adamo, segment vice president for U.S. service providers at Cisco Systems. Cisco is one of the companies helping devise the interface standards for the NGN. “You have to take all of these [different] devices into consideration and make sure that you deliver the functionality promised in the next-generation network,” Adamo said.

Each of these devices has its own inherent hardware technology, and depending on the communications provider, these devices may connect using different network technologies. Also, because existing systems won't disappear immediately, the interface must address capabilities for older public network-based devices.

The key element in providing access for all these systems will be to employ open standards wherever possible, which would help NGN designers ensure that the interface is seamless, according to Adamo. Open standards also will help ensure that yet-to-be-developed devices will be able to use the same interface.

“There's no way that any single vendor or service provider will provide all of the [telecom service] suites that people will use,” Adamo said. “We'll need to enable [interfaces for] multiservice providers, nomadic phones and PDA service providers. So we'll have to have an awful lot of intelligence in the network to make this go forward.”

Adamo added that packet-based technology will occupy the core of the network. “That's what you have to build around,” he said. The packet-based network will provide opportunities for enhanced services and reduced costs, Adamo added, so using packet-based interfaces is the most appropriate method for interconnecting packet-based networks. But if these networks must be interconnected using technologies like TDM and ISDN user part before the Next Generation Network (NGN) architecture is finalized, the core network won't be able to deliver all of the promised efficiencies.

The way in which signaling protocols are implemented within the network and the way in which services are provided at the interconnection point also must be specified, Adamo said. The network context and service definition for the interconnect will provide the framework for the packet interconnect specification. By working with ATIS, various standards bodies are moving forward in this arena, Adamo said, pointing to the dual-mode Wi-Fi and mobile phones that are just starting to come to market. In fact, while the NGN interfaces are significant, much of what is sketched out in ATIS' plan is based on existing infrastructure technology. One example of a sound basis for the NGN is EV-DO.

Interface development “has a positive start,” according to Miguel Pellon, vice president of standards for Schaumburg, Ill.-based Motorola. As its basis, the interface will rely on deploying IP multimedia subsystem (IMS) as an architectural component in the NGN. IMS can act as a bridge between the services available in the wired and wireless worlds.

This approach is the same as that used in developing 3G, Pellon said. In the NGN, 3G capabilities would be moved from the edges to the core of the network. Once standards are agreed upon, it will be relatively easy to converge on this common architecture. “By using a service platform [IMS] that is common between the wired and wireless world, the NGN will allow our industry to provide consistent services in different environments, leverage third-party developers of new services, get greater return from the investments in network infrastructure, and help integrate the various access networks by making services transportable across networks,” Pellon said. “So the interface will enable network capabilities regardless of a user's access device or location.”

In addition, the NGN should be able to support security efforts, notification of an application service provider's (ASP's) customer connectivity status, and the proxying of authentication, authorization and accounting to the ASP.

Securing the Interface

“The second key element is security,” Adamo said. “The server and network security need to have some standards. That will require a huge amount of work.”

For the security to work while maintaining interfaces with different devices, Adamo expects to see protections set in the core network. Otherwise, potential threats could take down large sections of the network. Security issues are so important that they often are tied to other areas such as the ability to provide intercarrier quality of service (QOS) standards, Adamo said.

In an effort to address that, ATIS is working in different countries to ensure that they all abide by the same centralized security standards. In addition, ATIS executives and leaders of other standards organizations such the International Telecommunication Union are meeting with carriers, network providers and others within the industry to ensure security and QOS. “There's not a lot of disagreement in the industry about this,” Adamo said.

Adamo expects usage of deep packet inspections at the core network level to help protect against these security threats. Some companies already do this for internal purposes, but the technology to perform this procedure at the core network level is just starting to become available, Adamo said.

Sophisticated QOS

Industry participants also agree that interfaces also will have a significant impact on QOS in the NGN. Among the specifications in ATIS' document is that QOS tools will ensure the availability of specific details about scaling voice, video and pure data communications. “When someone starts an e-mail session, he wants to know that there's capability to handle [the transmission] at all endpoints,” Adamo said.

The next-generation service provider could provide various levels of QOS to the ASP for communicating with its users. Though the ASP may not provide the customers' packet transport, it might relay information between customers of the application service. For example, in the current Internet model, an ASP providing e-mail services to its customers might relay the communications, but it wouldn't route the IP packets between customers based on an IP address. Yet an ASP typically would provide a value-added service that requires manipulating the information. For example, the e-mail provider might provide user-defined filters for an anti-spam service.

Similarly, the next-gen service provider could provide differentiated services or dynamically requested QOS. The ASP or its customer could request the QOS agreement. Or the carrier could maintain a business relationship with the ASP so that the cost of the QOS agreement is bundled into the ASP's service. For example, if a customer has an audio streaming or video streaming service, the ASP could generate the ASP-to-customer QOS request from the next-gen service provider without alerting the customer.

New applications also could be developed and provided over the NGN via software installed at each endpoint without requiring notification to the carrier network. Among the most typical ASP services currently offered are e-mail, gaming, e-commerce, Web hosting and content caching. New services ASPs could provide over the NGN could include Web services, grid networking and other services.

The next-gen service provider, on the other hand, would provide services such as transport that would enable the ASP to communicate efficiently with its customers. Basic transport includes routability and packet transport. Differential routing could reserve transport resources for specific customers, specific traffic types and specific times.

The next-gen service provider also could handle multicast services for the ASP. This would enable the ASP to more efficiently use its bandwidth while providing these services to customers. The multicast support would include support of multicast routing as well as enabling ASP customers to join and leave multicast groups for services offered by the ASP.

Similarly, the next-gen service provider could provide “anycast” services for ASP resources so that a resource would exist in multiple locations but have a “close” locator address.

Part of this capability includes accounting information the network must provide to the ASP. ATIS says this information should include packet flow-based accounting information as well as session accounting information. The core network should also provide the ASP with usage and performance metrics.

This accounting information will help different network participants determine where handoffs of communications occur for revenue and profit purposes. The more efficient the interface, the better profit margins that network participants should expect.

General requirements: interconnection

two major goals:

Specify a packet-based interconnection, suitable for carrier interconnect, that will support:

• Security
• QOS
• Reliability
• Billing support
• Service transparency
• Performance measurements, monitoring, codecs, etc.

Support interconnection between different classes of service providers (such as next-gen service providers and application service providers)

Source: ATIS