Glossary
P/F (Poll/Final bit)
One of the bits of a control octet in HDLC derivative level 2 link protocols. In commands it is called the Poll bit. In responses, the Final. Setting this bit to binary 1 in a command requires and immediate response. In a response, it indicates compliance with the command.
P(R)
Receive packet number in X.25 packet headers.
P(S)
Send packet number in X.25 packet headers.
Packet
A bit stream consisting of predefined fields that contain data, addresses, and control information. In the IEEE 802.3 environment, this structure is often referred to as the MAC frame. Packet is used in the Ethernet environment and is used in this guide because it is the more commonly understood term. Different protocols have different packet and frame specifications.
Packet Switching
A network technology in which data transfers are “packetized” and sent through the network one packet at a time. The network assume responsibility for routing the packets.
Permanent Virtual circuit
A permanent virtual circuit is a permanent association between two DDS, established by the user when subscribing to a
Physical Layer (PL)
Level 1 of the seven level OSI reference model defined by ISO. The physical layer provides for the physical transportation of cells across the network. It consists of physical medium dependent (PMD) and transmission convergence (TC) sublayers. Important categories are PDH, SDH and the physical media used on local premises for LANs.
Point-to-point configuration
A remote configuration that has two Advisors connected to each end.
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