Case Study

Case Study

The CDMA market historically developed under different rules than GSM, and CDMA2000 is expected to carry an even greater level of dissimilarities from UMTS despite their radio interfaces are closely related. CDMA2000 coverage is expected to continue to be concentrated around two large clusters in North America and East Asia (China, Japan, the Pacific Rim, and Korea), with deployments in Latin America, the Caribbean, and Eastern Europe possibly seeing negative growth. To date, the CDMA arena has been dominated by a few very large carriers, with smaller ones focused on serving niche markets and rural areas. In this case study, we analyze a CDMA2000 network (combined with the existing IS-95 network) built in the United States by a large carrier that recently merged with ACME Wireless, who, as described in the case study in the previous chapter, constructed a network in Europe. This newly established North American arm of ACME Wireless was recently renamed ACME USA.

This operator is now well funded and striving to provide its North American customers with an array of services similar or even surpassing that offered by its partners in Europe. Given the higher efficiency of the CDMA2000 air interface compared with TDM-based GSM GPRS, this just might be possible, and sufficient bandwidth should be available to provide mobile data users with advanced services. While GPRS operators, especially in urban centers like London, are already struggling to provide their subscribers with more than one time slot, this problem should be easier to address with CDMA2000's high-efficiency spread spectrum radio network.

ACME USA has been offering circuit data service for a few years now. Its core data network was based on industry-standard Interworking Functions (IWFs) concentrated in six data centers evenly covering the geography of the United States and hosting application servers and other equipment. While the network had been rolled out nationwide from the beginning, the take rates have not met expectations, which resulted in less profit but also in less data networking maintenance and support overhead, as well as in lower than originally planned rates of expansion. As a result all IWFs had been concentrated in one location to reduce maintenance costs. One of the few new features was a "Quick VPN" service marketed to business users based on Quick Net Connect architecture offered by the IWF manufacturer, allowing for fast private network access using L2TP tunneling to a private network instead of a traditional modem dial-up procedure.

Last year, ACME USA decided to upgrade their network to CDMA2000 by initially rolling out nationwide pilot packet data service. Under this plan, the existing data centers would be utilized to host PDSNs and HAs farms for plain Internet service, as shown in Figure 7.10. For this upgrade to be successful the radio equipment requires software and hardware upgrades, MSCs must be augmented with the PCFs implemented on a separate platform, and the network of PDSNs and HAs must be installed. ACME USA's engineering and marketing staff performed an extensive evaluation of Simple IP versus Mobile IP service and concluded that the Simple IP service must be rolled out first together with a marketing campaign that focuses on Mobile IP, which should be available shortly thereafter. The main reason for this decision was the absence of Mobile IP-capable handsets and the immaturity of Mobile IP clients offered for both Windows and Linux operating systems. It was also recognized that a Simple IP access network, as designed and supplied by a vendor of choice, was capable of supporting service offerings roughly similar to Mobile IP.

Click To expand Figure 7.10: ACME USA combined IS-95/CDMA2000 core network.

The solution offered by the vendor to address Simple IP deficiencies included a fully meshed network of PCFs and PDSNs, which would allow Simple IP subscribers to remain connected to the same PDSN even if the serving PCFs were changing. This would ensure that the IP addresses assigned to the mobiles remain constant for the duration of the session, allowing for voluntary tunneling and other IP address-sensitive applications. Along with a packet data network, ACME Wireless deployed a distributed AAA network and elected to host an AAA broker service in one of its data centers. It also planned to start marketing AAA brokerage service to other carriers simultaneously with the rollout of Mobile IP service.

Note 

ACME USA decided to support a combined public and private IP addressing scheme to facilitate versatility in offering of advanced IP services including upcoming Mobile VPN service.

Recognizing the complexity and immaturity of the Mobile VPN market, ACME USA decided to test-market a wide array of VPN options, including both voluntary and compulsory offerings. ACME USA offer for voluntary VPN users includes public routable IP address combined with service level guaranties, bandwidth management options, and different levels of security. Optional IPSec proxy service is also available and marketed to business customers such as partner ISPs as a part of remote wireless access outsourcing offer. The Customer Premise Equipment (CPE) program for voluntary VPN customers includes a variety of IPSec and PPTP software clients combined with support and location-based services.

Compulsory VPN service is also offered in an attractive package combining application hosting and proxying, address assignment outsourcing, and an extensive CPE (hardware/software bundles) program for enterprises including LNSs, IPSec gateways and HA equipment (for the soon-to-be-available Mobile IP service). An IPSec option is offered in combination with firewalling and bandwidth management and branded as a premium package, targeting large corporate accounts and government agencies. Both Simple and Mobile IP VPN services will be offered in standard form and rely on L2TP and Mobile IP tunneling, RADIUS AAA brokerage, and pilot SLAs with top-tier corporate customers.