Everyone is talking about VoIP and everyone wants a piece of the pie.

1. Service providers of various stripes: They provide the backbone and transport networks, enhanced services and business solutions directly to consumers, to businesses or to resellers. They include traditional ILECS and IXCs such as AT&T, MCI and Baby Bells (SBC, Verizon...), CLECS such as IDT, Covad..., Wireless Carriers (Sprint, NexTel..), "Pure VoIP" Service Providers such as Vonage, 8x8, Voiceglo, Cablevision, BT Broadband Voice, Cable and Wireless. Net-based carriers of carriers such as iBasis, ITXC, Equant, Level 3, Qwest, Global Crossing are "wholesale service providers", renting their private Net-based networks to carry voice traffic from other phone companies. A caller in the United States could make a long-distance call to Europe, and the call could be connected via an iBasis or ITXC Net-based network without the person even knowing it.
    
2. Equipment makers that provide equipment to carriers and to businesses.
   
   For carriers, these include Cisco Systems, Siemens Information and Communication Networks, Nortel Networks, Lucent Technologies and Alcatel. These produce the core switches that carriers have long installed in their central offices to terminate subscriber lines, aggregate them into long-distance trunks and route calls. Nortel, Avaya, Mitel, Alcatel, Vertical Networks, Cisco Systems, 3Com sell essentially the smaller versions of carrier switches to businesses. They terminate desktop phones, switch between them and pool the use of outgoing trunks to the wider world.
    
3. Integrators and Solution Providers
   
   From basic telephony set up and management to enhanced telephony including unified messaging, presence management conferencing, call center solutions etc
   
   Customer Relationship Management (CRM) / Call Centers handle customer service; predictive dialing; product inquiries; order entry; financial transactions; product/technical support; pre and post sales and support and more. Vendors such as NetSuite, Interactive Intelligence are noteworthy in this space.
   
   VidiTel, an application from Santa Cruz Networks Inc. that enables voice, video, and data conferencing over the Internet for only $40 per month. The solution requires customers to route traffic through a server. Other vendors sell voice over IP as a service and charge based on usage. IntraTel's Connect application can connect up to 16 users on a voice conference and as many as seven users for a videoconference, without the need for bridges, Web servers, or network modifications. The software runs about $550.
    
4. Application Providers
   
   Software vendors and PDA manufacturers are also feverishly working to provide a softphone application so consumers can use their PDA to make calls over 802.11 wireless LANs.
   
   Companies that produce Consumer Soft Phone, WebPhone, Skype, AttCallVantage client etc. have a large stake in the success of VoIP as well.
    
5. Consultants:
   
   Consulting companies are very important to Help companies sort out the VoIP choices, write and evaluate RFPs, help select the vendors and the implementation.
    
6. Supporting all this and often driving it are the Standards bodies and industry associations for VoIP. The chapter on Protocols and Standards covers this topic in greater detail.

The resources above provide more information on movers and shakers in the VoIP industry.