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The investment by telephony and Internet carriers, both incumbents and startups, in voice over IP (VoIP) services is growing worldwide. A key reason for this growth is the simple economics of call transport. IP telephony has matured to the point where it can offer a significant and cost-effective alternative to traditional circuit-switch solutions. New advances in the areas of voice QoS, scaling, management, provisioning, and call routing have made it possible for service providers to offer managed IP backbone networks for the seamless transport of voice, fax, and data.
As wholesale carriers typically have low margins, wholesale VoIP providers can realize considerable profit by carrying large quantities of compressed traffic to selected areas—while optimizing their use of the network. Telephony on an IP backbone allows the service provider to carry more traffic over the same trunks by using advances in compression and call processing. It also offers conditional routing techniques, so that a service provider can adjust traffic patterns dynamically, in near real time, to ensure the best termination price. In addition, service vendors can realize many advantages in the rapidly emerging "enhanced services over IP" market segment. These services can adapt to the more open, scalable, and flexible call model of Open Packet Telephony (OPT).
Wholesale voice is a growth market, with service providers building new capacity and launching new services. The primary wholesale service is long-distance transport and aggregation, with the key advantage that country-specific features and domestic calling regulations are not required. Principal beneficiaries are developing countries, where in many cases the quality of VoIP is superior to that of traditional PSTN service.
This chapter presents the following major topics:
The Cisco Wholesale Voice Solution provides service providers (SPs) with the required architecture design, network components, software features, functional areas, and provisioning methodologies needed to run a VoIP wholesale service. With an understanding of the concepts underlying the architecture, including interconnect topologies, components, and a variety of important issues that must be considered, the SP can then deploy options from a set of configuration templates. The result is a wholesale network that allows the SP to sell unbranded voice services to retailers, such as Internet telephony service providers (ITSPs), application service providers (ASPs), interexchange carriers (IXCs), or Post Telephone and Telegraph administrations (PTTs).
Central to the delivery of wholesale voice services are voice points of presence (POPs), which are interconnected to other service providers. The specific recommended components and design methods are determined by the type of interconnection or "call topology" that the wholesale SP is supporting. These call topologies are used to build a set of deployment templates for an SP to enable wholesale applications. Figure 1-1 illustrates the interconnection possibilities that a wholesale VoIP provider must accommodate.
The Cisco Wholesale Voice Solution is a set of solutions and network design and configuration templates that provide trunk-level transport of global switched telephone traffic distributed over VoIP. Calls originate in the PSTN, are routed through IXCs, and are handed off to a wholesale VoIP carrier for transport. To the end user, the service looks like any other long-distance call, except that it is less expensive. To the originating long-distance carrier, the wholesale carrier is only one of a number of termination options.
By using OPT distributed architectures, the Cisco Wholesale Voice Solution maintains separate call control, connection control, and transport planes. At the heart of the solution are Cisco gateways (GWs), gatekeepers (GKs), and directory gatekeepers (DGKs), as well as an IP backbone. This solution will provide other network providers with connectivity between basic telephone areas and international routes. (Local residential services and features will not be provided.) The remaining components of the solution are third-party shared services that will vary with each application—such as settlement servers, billing servers, and AAA (authentication, authorization, and accounting) servers, among others.
The Cisco Wholesale Voice Solution provides the following benefits:
Table 1-1 briefly lists features that are provided with the Cisco Wholesale Voice Solution.
The following customers will be the prime beneficiaries of the Cisco Wholesale Voice Solution:
Figure 1-2 summarizes all of the components that may be needed to provide Cisco Wholesale Voice Solution services. The various scenarios discussed later in this document focus on the specific components needed for each scenario.
Naturally, not all services will use all components. The service models presented below can overlap with respect to a given customer. For example, one customer could be both a minutes aggregator/terminator as well as a clearinghouse. Conversely, although a clearinghouse is most often viewed as part of a solution, a single customer providing clearinghouse services is also a candidate for the Cisco Wholesale Voice Solution. A key feature of the Cisco Wholesale Voice Solution is its ability to support various mixes of the following services to suit the needs of a single or multiple (partnering) service providers.
The Cisco Wholesale Voice Solution supports the following services:
This service allows wholesale network providers to collect traffic from multiple originating providers, then aggregate and deliver it to termination providers they select. These providers may include target greenfields, resellers, dial-around callback operators, and international ISPs.
The Cisco Wholesale Voice Solution supports the originating carrier, who profits up front by handing calls over to a VoIP wholesaler. Termination settlement rates are generally lower than PSTN termination rates—the key reason why long-distance carriers will choose a VoIP carrier for termination. Furthermore, termination bandwidth is often available over VoIP to countries where PSTN termination is unavailable (for example, because of congested international gateway facilities).
Voice, modem, and fax calls are supported. The interfaces supported are SS7, T1/E1 PRI, E&M, and R2. Average call success rate is as good as or better than that provided by PSTN carriers. Furthermore, voice quality, including echo cancellation, is uncompromised.
Key features of this service include the following:
As part of Service A, the Cisco Wholesale Voice Solution supports termination services for ASP-originated calls. In this carrier-to-carrier service, the ASP originates the call, often over an Internet-enabled PC-telephony application, or through a PSTN portal for cellular phone callers. The ASP provides precall services, such as content delivery (prerecorded messages, voice mail, private number dialing) or supervision-related services ("find me/follow me"). The ASP then needs to hand any long-distance calls off to a wholesale carrier for termination by the PSTN.
For the key issues related to this service for various call topologies, refer to "Service A: Minutes Aggregation and Resale (Including ASP Termination)."
The Cisco Wholesale Voice Solution supports both prepaid and postpaid calling-card services, as described below. These are both subscriber services. Figure 1-3 illustrates, as an example, the components and signaling required to provide calling card services for international calls.
In the prepaid service, a wholesale VoIP carrier can host prepaid services for multiple service providers on their infrastructure. In addition, most prepaid service providers use VoIP wholesalers to terminate long-distance calls that are placed by prepaid subscribers.
Using the interactive voice response (IVR) feature in the Cisco VoIP gateways, and real-time authorization and call accounting systems provided byCisco Ecosystem Partners, service providers can offer this service over a VoIP network and lower the cost and deployment time of calling-card services.
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Note Cisco has identified leading solution providers with which to partner in offering end-to-end benefits. These providers are collectively known as the Cisco New World Ecosystem. For more information about the Ecosystem Partner community, visit http://www.cisco.com/public/Partner_root.shtml. |
Like the prepaid service, postpaid service can be hosted by a wholesale VoIP carrier. An example is basic calling that is accessed by the 800 prefix, a calling card number, or a PIN. Postpaid is similar to the prepaid service, except that with postpaid the authorization is not tied to call rating. Consequently, call rating does not have to happen in real time, and there may be more partner billing-system options that perform adequately at scale. After calls are made, a billing system contracted by the company charges the carrier.
For the key issues related to this service for various call topologies, refer to "Service B: Card Services (Prepaid and Postpaid)."
Where multiple partners are involved, as will often be the case, the above services may require the assistance of clearinghouse services for billing, settlement, and invoicing. These services can be based on Open Settlements Protocol (OSP), or on other methods of mediation and settlement, including AAA/RADIUS. Where the services are OSP based, the Cisco Wholesale Voice Solution supports call termination agreements through support for OSP in Cisco devices.
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Note For more information about OSP, see "Open Settlements Protocol (OSP) Clearinghouse Solution." |
The following enhancements are provided to support the services offered by Cisco Wholesale Voice Solution:
As an enhancement to simple carrier-interconnect applications, the Cisco Wholesale Voice Solution makes it possible to route a call to different destination carriers. The wholesaler has the same considerations as with simple carrier-interconnect models, but with slightly increased call-routing responsibilities. For more information, refer to Limited Egress Carrier-Sensitive Routing in "Deploying Service Options."
Cisco-based wholesaler VoIP networks can interconnect with a Clarent-based service provider (http://www.clarent.com). For more information, refer to Interconnect to Clarent-Based Clearinghouses in "Deploying Service Options."
The Cisco Wholesale Voice Solution architecture builds upon existing Cisco products to provide services that will run over the service provider's VoIP infrastructure. To understand that architecture, including functional areas and components, proceed to "Solution Architecture."
Posted: Wed Jan 22 15:19:48 PST 2003
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