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Basic Gateway TCP/IP Wireless USB
SBG940 User Guide
126
P
packet
The unit of data that is routed between the sender and destination on the Internet or other
packet-switched network. When data such as an e-mail message or other file is sent over the Internet,
IP on the sender divides the data into uniquely-numbered packets. The packet header contains the
source and destination IP addresses. The individual packets may travel different routes. When all
packets arrive at the destination, IP at that end reassembles the packets. The header and the data
can vary in length. Packet and datagram are similar in meaning.
packet-
switched
A scheme to handle transmissions on a connectionless network such as the Internet. An alternative is
circuit-switched.
PacketCable
A CableLabs-led project to define a common platform to deliver advanced real-time multimedia
services over two-way HFC cable plant. Built on DOCSIS 1.1, PacketCable networks use IP
technology as the basis for a highly-capable multimedia architecture.
pass-through
A pass-through client on the SBG940 LAN obtains its public IP address from the cable provider DHCP
server.
PAT
Port Address Translation
PCI
Peripheral Component Interconnect
PCMCIA
The Personal Computer Memory Card International Association sets international standards for
connecting peripherals to portable computers. Laptop computers typically have a PCMCIA slot that
can hold one or two PC Cards to provide features such as Ethernet connectivity.
PDA
personal digital assistant
PDU
A protocol data unit is a message containing operational instructions used for SNMP. The basic
SNMP V2 PDU types are get-request, get-next-request, get-bulk-request, response, set-request,
inform-request, and trap.
periodic
ranging
Ranging that is performed on an on-going basis after initial ranging has taken place.
physical layer
Layer 1 in the OSI architecture. It provides services to transmit bits or groups of bits over a
transmission link between open systems. It entails the electrical, mechanical, and handshaking
procedures.
piggybacking
A process that occurs when a cable modem simultaneously transmits data and requests additional
bandwidth.
PING
A network utility that tests host reachability by sending a small packet to the host and waiting for a
reply. If you PING a computer IP address and receive a reply, you know the computer is reachable
over the network. It also stands for “Packet InterNet Groper.”
PMD
The physical media-dependent sublayer of the physical layer which transmits bits or groups of bits
over particular types of transmission links between open systems. It entails the electrical, mechanical,
and handshaking procedures.
point-to-point
Physical connection made from one point to another.
POTS
The “plain old telephone service” offered through the PSTN; basic analog telephone service. POTS
uses the lowest 4 kHz of bandwidth on twisted pair wiring.
port
On a computer or other electronic device, a port is a socket or plug used to physically connect it to the
network or to other devices.
in TCP/IP, a port is a number from 0 to 65536 used logically by a client program to specify a server
program. Ports 0 to 1024 are reserved