Technical data

© 2012 Meru Networks, Inc. Glossary 335
Pooling
Virtualization technique in which multiple physical resources are combined into a single
virtual resource. Examples include the multiple disk drives in a virtual storage array, the
multiple CPUs in a modern server and the multiple access points in a Meru Virtual Cell. The
main advantages of pooling are agility, simplified management and economies of scale:
Resources can be moved between applications on demand, reducing the need for
over-provisioning and freeing applications or users from dependence on a single piece of
limited infrastructure.
PC card
A removable, credit-card-sized memory or I/O device that fits into a Type 2 PCMCIA stan-
dard slot, PC Cards are used primarily in PCs, portable computers, PDAs and laptops. PC
Card peripherals include Wi-Fi cards, memory cards, modems, NICs, hard drives, etc.
PCI
A high-performance I/O computer bus used internally on most computers. Other bus types
include ISA and AGP. PCIs and other computer buses enable the addition of internal cards
that provide services and features not supported by the motherboard or other connectors.
PDA
Smaller than laptop computers but with many of the same computing and communication
capabilities, PDAs range greatly in size, complexity and functionality. PDAs can provide
wireless connectivity via embedded Wi-Fi Card radios, slide-in PC Card radios, or Compact
Flash Wi-Fi radios.
PEAP
Protected Extensible Authentication Protocol. An extension to the Extensible Authentica-
tion Protocol with Transport Layer Security (EAP-TLS), developed by Microsoft Corporation.
TLS is used in PEAP Part 1 to authenticate the server only, and thus avoids having to
distribute user certificates to every client. PEAP Part 2 performs mutual authentication
between the EAP client and the server.
peer-to-peer
network
A wireless or wired computer network that has no server or central hub or router. All the
networked PCs are equally able to act as a network server or client, and each client
computer can talk to all the other wireless computers without having to go through an
access point or hub. However, since there is no central base station to monitor traffic or
provide Internet access, the various signals can collide with each other, reducing overall
performance.
PHY
The lowest layer within the OSI Network Model. It deals primarily with transmission of the
raw bit stream over the PHYsical transport medium. In the case of Wireless LANs, the
transport medium is free space. The PHY defines parameters such as data rates, modula-
tion method, signaling parameters, transmitter/receiver synchronization, etc. Within an
actual radio implementation, the PHY corresponds to the radio front end and baseband
signal processing sections.
plenum
The ceiling plenum is the volume defined by the area above the back of the ceiling tile,
and below the bottom of the structural slab above. Within this plenum is usually found a
combination of HVAC ducts, electrical and electronic conduits, water pipes, traditional
masking sound speakers, etc. Networking equipment needs to be plenum rated to certify
that it is suitable for deployment in this area.
PoE
Power over Ethernet. A technology defined by the IEEE 802.3af standard to deliver dc
power over twisted-pair Ethernet data cables rather than power cords. The electrical
current, which enters the data cable at the power-supply end and comes out at the device
end, is kept separate from the data signal so neither interferes with the other.