server Infrastructure) A specialized, shared computer on the LAN An Internet security protocol for routing or in a carrier's network containing files such packets on the Internet. It adds encryption as e-mail or applications. It can be used to between databases called Internet regis- handle sharing of printers, e-mail, and other tries (centralized databases with Internet applications. Glossary set-top box utilities. A goal is to use energy more effi- A device connected to a television that allows ciently by monitoring usage patterns. access to various content, including pay-per- view programming. Set-top boxes can be SMS (Short Message Service) used to distribute content to other TVs and Short, 160-character (including header devices. Newer models contain hard drives address information) text messages that and multiple tuners. They can be used to can be transmitted between digital cellular watch one program while recording a differ- telephones. ent show, and to pause and rewind programs. SMTP (Simple Mail Transfer Protocol) signaling gateway The e-mail protocol portion of TCP/IP used A type of media gateway that converts sig- on the Internet. Having an e-mail standard naling from IP networks to that compatible that users adhere to enables people on diverse with traditional, circuit-switched networks, LANs to send e-mail to one another. and vice versa. softphone SIM (Subscriber Identification Telephone functionality on a personal com- Module) puter in VoIP systems. People with soft- A clip-on or internal card with microchips in phone-equipped laptops can use their VoIP mobile handsets that store user identity and remotely. other information such as speed-dial lists and e-mail addresses. CDMA phones do not have softswitch SIM cards. Used in converged enterprise and carrier net- works that carry VoIP traffic. Softswitches SIP (Session Initiation Protocol) are built on standard computer processors A signaling protocol used to establish ses- and use standards-based protocols, which sions over IP networks, such as thos