3Com 3C892 manual Glossary

GLOSSARY 125

PRI Primary Rate Interface. A PRI line is one of two access methods to the ISDN; BRI is the other. In North America, each PRI consists of twenty-three 64 Kbps B channels and one 64 Kbps D channel.

router A router is a device that links networks.

SPID Service Profile Identifier. If required, this number is supplied to you by the telephone company. Typically, if your ISDN line has only one telephone number, a SPID is not required.

TCP/IP Transmission Control Protocol/Internet Protocol. TCP/IP is a standardized communications protocol which allows different types of devices to communicate with each other over LANs and WANs.

TollMizer TollMizer (also referred to as Switched 56 Permissive or Data Over Voice) makes a 56 Kbps data call over a voice circuit, allowing you to save the typical cost difference between a voice and data call. Note that the destination you are calling must also support this feature.

UDP User Datagram Protocol. A connectionless protocol within TCP/IP that converts application-generated data messages into packets that can be sent via IP. UDP does not check for transmission errors therefore it does not perform retransmission. Reliability is dependent upon the application. Note that because it does not perform checking, UDP is more efficient than TCP. UDP is commonly used for Internet games.

VPN A virtual private network is a secure, private data network that is established over the Internet resulting in significant cost savings from using local, toll free access numbers. Also, because the existing Internet backbone is used, there is less investment needed in private network infrastructure. See also PPTP.