## Appendix B: Glossary of Terms

## Terms Used in This Guide

802.1D 802.1Q | 802.1Q defines a layer 2 frame structure that supports VLAN identification and a QoS mechanism usually referred to as 802.1D.
ARP | Address Resolution Protocol, used, for example, to verify that the IP address provided by the DHCP server is not in use by another IP telephone.
CLAN | Control LAN, type of Gatekeeper circuit pack.
DHCP | Dynamic Host Configuration Protocol, an IETF protocol used to automate IP address allocation and management.
DiffServ | Differentiated Services, an IP-based QoS mechanism.
DNS | Domain Name System, an IETF standard for ASCII strings to represent IP addresses. The Domain Name System (DNS) is a distributed Internet directory service. DNS is used mostly to translate between domain names and IP addresses. Avaya 9600 Series IP Telephones can use DNS to resolve names into IP addresses. In DHCP, TFTP, and HTTP files, DNS names can be used wherever IP addresses were available as long as a valid DNS server is identified first.
Gatekeeper | H.323 application that performs essential control, administrative, and managerial functions in the media server. Sometimes called CLAN in Avaya documents.
H.323 | A TCP/IP-based protocol for VoIP signaling.
HTTP | Hypertext Transfer Protocol, used to request and transmit pages on the World Wide Web.
HTTPS | A secure version of HTTP.
IETF | Internet Engineering Task Force, the organization that produces standards for communications on the internet.
LAN | Local Area Network.
MAC | Media Access Control, ID of an endpoint.
QoS | Quality of Service, used to refer to several mechanisms intended to improve audio quality over packet-based networks.
Unnamed Registration | Registration with Avaya Communication Manager by an IP telephone with no extension. Allows limited outgoing calling.
TLS | Transport Layer Security, an enhancement of Secure Sockets Layer (SSL). TLS is compatible with SSL 3.0 and allows for privacy and data integrity between two communicating applications.
Unnamed Registration | Registration with Avaya Communication Manager by an IP telephone with no extension. Allows limited outgoing calling.
VLAN | Virtual LAN.
VoIP | Voice over IP, a class of technology for sending audio data and signaling over LANs.