RAD Data comm E1/T1, Modular Access Device with Integrated Router Appendix D Glossary

Appendix D Glossary FCD-IPMInstallation and Operation Manual

Spoofing - Spoofing is a technique used to reduce network overhead, especially in a WAN. Some network protocols send frequent packets for management purposes. These can be routing updates or keep-alive messages. In a WAN this can introduce significant overhead, due to the typically smaller bandwidth of WAN connections.

Spoofing reduces the required bandwidth by having devices, such as bridges or routers, answer for the remote devices. This fools (spoofs) the LAN device into thinking the remote LAN is still connected, even though it's not. The spoofing saves the WAN bandwidth, because no packet is ever sent out on the WAN.

SPX (Sequenced Packet Exchange) - SPX is a transport layer protocol built on top of IPX. SPX is used in Novell NetWare systems for communications in client/server application programs, e.g., BTRIEVE (ISAM manager).

Static Station - A static station is a host, which is added manually to an ARP or LAN table.

Stop Bit - Stop Bits mark the end of a unit of transmission (normally a byte or character). In serial communications, where each bit of the message is transmitted in sequence, stop bits are extra "1" bits which follow the data and any parity bit.

Synchronous Transmission - Synchronous transmission is when data bits are transmitted at a fixed rate. The sender and the receiver are synchronized.

TCP (Transmission Control Protocol) - TCP is the most common transport layer protocol used on Ethernet and the Internet.

TCP is built on top of Internet Protocol (IP) and is nearly always seen in the combination TCP/IP (TCP over IP). It adds reliable communication, flow-control, multiplexing and connection-oriented communication. It provides full-duplex, process-to-process connections.

TCP is defined in STD 7, RFC 793.

TCP/IP stack (Transmission Control Protocol over Internet Protocol) -TCP/IP stack is the standard Ethernet protocols incorporated into 4.2BSD UNIX. While TCP and IP specify two protocols at specific layers, TCP/IP is often used to refer to the entire DoD protocol suite based upon these, including Telnet, FTP, UDP and RDP.

TFTP (Trivial File Transfer Protocol ) - TFTP is a simple file transfer protocol used for down-loading boot code to diskless workstations.

Throughput - Throughput is the amount of data a communications channel can carry, usually in bytes per second.

UDP (User Datagram Protocol) - UDP is an Internet standard network layer, transport layer and session layer protocols which provide simple but unreliable datagram services. It adds a checksum and additional process-to-process addressing information. UDP is a connectionless protocol which, like TCP, is layered on top of IP.

UDP is defined in STD 6, RFC 768.

WAN (Wide Area Network) - A WAN is a network, usually constructed with serial lines, extending over distances greater than one kilometer.

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