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Glossary
packet mode connections
Packet mode connections are typically passed
through the router or remote access device. This includes Point-to-Point Pro-
tocol (PPP) sessions.
packet switch
A physical device that makes it possible for a communica-
tion channel to share several connections, its functions include finding the
most efficient transmission path for packets.
packet switching
A networking technology based on the transmission of
data in packets. Dividing a continuous stream of data into small units--
packets--enables data from multiple devices on a network to share the same
communication channel simultaneously but also requires the use of precise
routing information.
PAD
Packet assembler and disassembler: Used to buffer incoming data that
is coming in faster than the receiving device can handle it. Typically, only
used in X.25 networks.
PAP
Password Authentication Protocol: In Point-to-Point Protocol (PPP)
networks, a method of validating connection requests. The requesting
(remote) device must send an authentication request, containing a password
and ID, to the local router when attempting to connect. Unlike the more
secure CHAP (Challenge Handshake Authentication Protocol), PAP sends
the password unencrypted and does not attempt to verify whether the user
is authorized to access the requested resource; it merely identifies the remote
end. See also: CHAP.
parity checking
A method of error-checking in data transmissions. An
extra bit (the parity bit) is added to each character or data word so that the
sum of the bits will be either an odd number (in odd parity) or an even
number (even parity).
partial mesh
A type of network topology in which some network nodes
form a full mesh (where every node has either a physical or a virtual circuit
linking it to every other network node), but others are attached to only one
or two nodes in the network. A typical use of partial-mesh topology is in
peripheral networks linked to a fully meshed backbone. See also: full mesh.
PAT
Port Address Translation: This process allows a single IP address to
represent multiple resources by altering the source TCP or UDP port
number.
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