■■ Softswitches
■■ Media servers
■■ Network elements for QoS
■■ Policy servers for QoS, for classes of users and applications
■■ Voice-quality-monitoring network probes
■■ Network management systems for all of these
■■ Information Technology (IT) systems for all the above
■■ Network engineering and integration costs for VoIP.
By contrast, the software applications in the peer nodes actually replace
the VoIP, IM, and so on for ßnetwork infrastructure.
■■ Minimal or no operations costs because of the self-organizing nature of
P2P. Payroll in existing telecom operations increases with the number of
systems and network elements, and also with the complexity of the
infrastructure. In P2P systems, software upgrades for downloading by
users replaces the operations cost for VoIP networks.
■■ Minimal information technology (IT) costs. IT in telecom is often more
expensive that the voice network itself that IT has to support. The only
IT system for P2P is the customer authentication and logon server, fun-
damentally not very different from any other e-commerce system.
■■ No service level agreements with customers and with other connected
networks that require a significant legal staff and a business development
staff.
■■ The only residual cost for P2P Internet communications are the gateway
services to the PSTN and to mobile 2G and 3G networks. Large costs
are incurred in these networks for the expensive accounting systems to
support pricing plans, promotions, settlements, and so on.Summary
The explosion of Internet P2P computing on the Internet has also produced
Internet P2P communications. The prestandard P2P system Skype is, by far,
the biggest IM and VoIP service provider on a global scale.
P2P overlay networks are self-organizing systems and have significant
advantages compared to the customary client-server architecture. P2P com-
munications require no VoIP infrastructure. P2P communications based on SIP
can use the Bamboo protocol for Distributed Hash Tables and have most of the350 Chapter 20