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Appendix B: Glossary
offsite connection to office
: See teleworking.
optical fiber
: A solid glass or plastic fiber that carries light pulses for fiber optic networks. Advantages of optical fiber include
high speed, high reliability, ability to send transmissions over long distances without significant degradation, immunity to electro-
magnetic interference and radiofrequency interference, and high security. Optical fiber generally uses an SFP connector. Optical
fiber is available in single-mode fiber or multimode fiber.
originating address
: See source address.
PAT
: See port address translation.
PCI
: See Peripheral Component Interconnect.
PEP
: See performance enhancement proxy.
perfect forward secrecy (PFS)
: Use of uniquely derived keys. PFS is part of IKE. PFS comprises the following principles:
• Material used to derive one key cannot be used to derive additional keys.
• A key cannot be used to derive another key.
• Discovery of a key can endanger only transmissions protected by that key.
performance enhancement proxy (PEP)
: A routine that satellite ground stations use to mitigate the delay in satellite networks.
PEPs spoof TCP sessions with endpoints outside the satellite network, thereby mitigating the delays inherent in satellite networks.
(500 ms is a typical TCP roundtrip response time over a satellite network without PEP.)
Peripheral Component Interconnect (PCI)
: A standard for a 64-bit local bus (generally implemented as a 32-bit bus) that runs
at 33 MHz or 66 MHz. Developed by Intel Corporation but not specific to any line of microprocessors, PCI is a widely used
standard for expansion cards.
NOTE: Using 32 bits at 33 MHz, PCI has a throughput of 133 Mbytes/sec.
PFS
: See perfect forward secrecy.
PKC
: See public-key cryptography.
plain old telephone service (POTS)
: Analog telephone service that, in many areas, connects landline phones and other end-line
customer devices to the public switched telephone system (PSTN). Faxes, modems, and many other business devices still use POTS
to transmit digital information.
NOTE: The terms “POTS” and “PSTN” are often used interchangeably, despite their references to different entities.
port address translation (PAT)
: Inclusion of port numbers when implementing network address translation.
NOTE: NAT methods generally include PAT.
POTS
: See plain old telephone service.
pre-shared key
: See secret key.
NOTE: A pre-shared key is not a generated shared secret.
private key
: The key that the holder of a key pair uses for encryption and decryption of communication with others. The private
key is never shared. The private key’s counterpart is the public key. Also see asymmetric encryption.
psophometric weighting
: A method of weighting when measuring circuit noise.
NOTE: ITU is studying recommendations for psophometric weighting in telecommunication.
PSTN
: See public switched telephone system.
public key
: The key that, when communicating with the holder of a private key, other entities use for encryption and decryption.
The public key is freely available to anyone. The private key and its counterpart public key constitute the key pair. Also see
asymmetric encryption.
