WiMax Operator's Manual

CHAPTER 6 ■ BEYOND ACCESS 139
instruments are used that convert the voice signal to IP right at the deskset. Each approach
requires a different type of deployment with a different array of equipment components.
Wireless broadband operators face a choice of terminating local phone traffic over their
own networks at either a class 5 switch or a softswitch equivalent or, alternatively, ceding the
switching function to some other service provider. In most cases, the ownership of a traditional
class 5 switch is out of the question for the wireless operator, so a softswitch is the only real
choice unless the wireless operator chooses to route phone traffic through the exchange of the
local incumbent and utilize that carrier’s circuit switch.
If a softswitch is employed, the wireless operator will need to lease a circuit connection to
a class 4 or tandem switch operated by a long-distance service provider. Both long-distance
calls and local calls made to parties who subscribe to landline telephone services will then
have to be routed through that class 4 switch. The local calls to nonsubscribers will then be sent
back to the incumbent telco’s class 5 switch and from there to the designated party. Obviously,
some complex issues and difficult decisions are involved in setting up an IP voice service.
Quite a number of service models can be built around IP telephony, and I will discuss
them in detail in the next chapter. The long-term profitability of those models is at issue, however.
Voice is becoming an increasingly price-eroded, low-margin business, and IP telephony
will surely accelerate that trend because it reduces the cost of transit and because IP voice has
been positioned as a price-competitive product by those carriers offering it. To make matters
worse, various peer-to-peer Internet telephony programs have recently been disseminating
through the online community that completely eliminate the need for a local carrier and that
route all telephone traffic through the Internet service provider (ISP) with no billable minutes
being involved. IP voice services may be becoming cheaper to provision, but they also appear
likely to command lower prices over time and ultimately lower margins for the service provider.
Some industry analysts have concluded that voice telephony will eventually become a
no-charge amenity that is simply included in a basic service package. Figure 6-3 shows a voiceover
IP connection to the PSTN.
Figure 6-3. Voice-over IP, courtesy of Alvarion