Avaya 38DHB0002UKDD manual Glossary Cont, HyperTerminal, Internet Group Management Protocol IGMP

Page 140 Glossary

Glossary (Cont.)

Flash Completely delineated, flash is a solid-state, non-volatile, re-writable memory. Much like RAM (Random Access Memory) flash uses memory cells to store electronic bits of data, but flash differs from RAM in two respects. First, flash is non-volatile, unlike DRAM and SRAM which must have constant power to retain data. Second, flash differs from RAM in the way the read/write process works, since flash can only write data to a previously erased block of memory. Some types of flash have a random-read feature like RAM, while others read data sequentially, similar to a disk drive.

This combination of features makes flash well-suited both for file storage applications - particularly portable or removable storage - and for XIP (eXecute In Place) and code-storage applications.

FTP File Transfer Protocol (FTP). To download files from or upload files to remote computer systems, via the Internet’s File Transfer Protocol. The user needs an FTP client to transfer files to and from the remote system, which must have an FTP server. Generally, the user also needs to establish an account on the remote system to FTP files, although many FTP sites permit the use of anonymous FTP.

Gopher An Internet utility for finding textual information and presenting it to the user in the form of hierarchical menus, from which the user selects submenus or files that can be downloaded and displayed. One Gopher client may access all available Gopher servers, so the user accesses a common “Gopherspace”. The name of the program is a three-way pun. It is designed to go for desired information, it tunnels through the Internet and digs the information up, and was developed at the University of Minnesota (whose athletic teams are named the Golden Gophers). Gopher is being subsumed by the World Wide Web.

H.323 A standard approved by the International Telecommunication Union (ITU) that defines how audiovisual conferencing data is transmitted across networks. H.323 should enable users to participate in the same conference even though they are using different videoconferencing applications.

HTTP Hypertext Transfer Protocol. The client/server protocol used to access information on the World Wide Web.

HyperTerminal

Allows you to connect two computers with a modem so you can send and receive files, or connect to computer bulletin boards and other information programs. For example, you can use HyperTerminal to connect to an online service and to download files from a bulletin board on that service. You can also use HyperTerminal to connect a computer directly to another computer, such as a debugging terminal.

Internet Group Management Protocol (IGMP)

The standard for IP multicasting in the Internet. It is used to establish host memberships in particular multicast groups on a single network. The mechanisms of the protocol allow a host to inform its local router, using Host Membership Reports, that it wants to receive messages addressed to a specific multicast group.

IP Header Compression (IPHC - RFC 2507 and RFC 2508)

IPHC reduces the IP/UDP/RTP headers to two bytes for most packets in the case where no UDP checksums are being sent, or four bytes with checksums. IPHC therefore significantly reduces WAN bandwidth requirements per voice call.

IP Office applies IPHC to all traffic types i.e. voice signalling/traffic and data. However, some IP protocols yield a better compression ratio.

IPHC imposes process overheads which can become counter-productive at higher WAN speeds. It is for this reason that IP Office will not perform IP Header compression at speeds above 1024Kbps.

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	38DHB0002UKDD – Issue 7 (22/11/02)