gloss_P

P

packet switching.

In packet switching, data is segmented into packets and sent across a circuit shared by multiple subscribers. As the packet travels over the network, switches read the address and route the packet to its proper destination. X.25 and frame relay are examples of packet-switching services.

packet.

A packet is a collection of bits that includes data and control information, which is sent from one node to another.

peer-to-peer.

In a peer-to-peer architecture, two or more nodes can directly initiate communication with each other; they do not need an intermediary. A device can be both the client and the server.

personal communications services (PCS).

PCS is a marketing category of applications that includes wireless local and personal area communications for portable and desktop computers, wireless notepad and messaging devices, and wireless office and home telephone systems. The FCC is in the process of allotting both licensed and unlicensed frequency ranges for PCS-based devices.

Physical layer.

The lowest layer of the OSI model is the Physical layer, and it defines the signaling and interface used for transmission media.

Point-to-Point Protocol (PPP).

PPP provides router-to-router and host-to-network connections over asynchronous and synchronous connections. It is considered a second-generation Serial Line Internet Protocol (SLIP).

point-to-point.

A point-to-point link is a direct connection between two locations.

Presentation layer.

The sixth , or Presentation layer, of the OSI model is responsible for data encoding and conversion.

Primary Rate Interface (PRI).

PRI ISDN is a T1 service that supports 23 64Kbit/sec B channels plus one 64Kbit/sec D channel.

propagation delay.

Propagation delay is the time it takes for a bit to travel across the network from its transmission point to its destination.

protocol.

A protocol is a standardized set of rules that specify how a conversation is to take place, including the format, timing, sequencing and/or error checking.

proxy agent.

A proxy agent is software that translates between an agent and a device that uses a different management information protocol. The proxy agent communicates the data to the network manager.

public data network (PDN).

A PDN is a network operated by a government or service provider that offers wide area services for a fee. Examples are networks from British Telecom and Infonet.