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Glossary

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permanent virtual circuit (PVC). Commonly used in Frame Relay to deter-
mine the far-end node's TCP/IP address by sending the Inverse ARP request
to the local DLCI.

Internet Protocol: Defined in RFC 791, it is a network layer protocol

that is part of the TCP/IP stack and allows connectionless service. IP fur-
nishes an array of features for addressing, type-of-service specification, frag-
mentation and reassembly, and security.

IP address

Often called an Internet address, this is an address uniquely

identifying any device (host) on the Internet (or any TCP/IP network). Each
address consists of four octets (32 bits), represented as decimal numbers sep-
arated by periods (a format known as "dotted-decimal"). Every address is
made up of a network number, an optional subnetwork number, and a host
number. The network and subnetwork numbers together are used for
routing, while the host number addresses an individual host within the net-
work or subnetwork. The network and subnetwork information is extracted
from the IP address using the subnet mask. There are five classes of IP
addresses (AE), which allocate different numbers of bits to the network,
subnetwork, and host portions of the address. See also: CIDR, IP, and
subnet mask.

IPCP

IP Control Program: The protocol used to establish and configure IP

over PPP. See also: IP and PPP.

IP multicast

A technique for routing that enables IP traffic to be repro-

duced from one source to several endpoints or from multiple sources to
many destinations. Instead of transmitting only one packet to each indi-
vidual point of destination, one packet is sent to a multicast group specified
by only one IP endpoint address for the group.

IPX

Internetwork Packet eXchange: Network layer protocol (layer 3) used

in Novell NetWare networks for transferring information from servers to
workstations. Similar to IP and XNS.

IPXCP

IPX Control Program: The protocol used to establish and configure

IPX over PPP. See also: IPX and PPP.

IPXWAN

Protocol used for new WAN links to provide and negotiate line

options on the link using IPX. After the link is up and the options have been
agreed upon by the two end-to-end links, normal IPX transmission begins.

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