
Glossary
| Optical carrier | See OC. | 
| Optical fiber | See  | 
P
| Packet | Logical grouping of information that includes a header containing control information and (usually) | 
| 
 | user data. Packets are most often used to refer to network layer units of data. The terms datagram, | 
| 
 | frame, message, and segment are also used to describe logical information groupings at various layers | 
| 
 | of the OSI reference model and in various technology circles. | 
| Packet Over SONET | See POS. | 
| Packet switching | Networking method in which nodes share bandwidth with each other by sending packets. | 
| Parallel Express | See PXF Network Processors. | 
| Forwarding | 
 | 
| PCMCIA Flash disk | A portable  | 
| card | technology to store data. PCMCIA stands for Personal Computer Memory Card International | 
| 
 | Association, which sets the standard for this technology. Also called PC card. | 
| PEM | Power entry module. A hardware module that distributes power to the chassis. | 
| Performance | See PRE. | 
| Routing Engine | 
 | 
| Point of Presence | See POP. | 
| See PPP. | |
| Protocol | 
 | 
| POP | Point of presence. A physical location where an interexchange carrier installed equipment to | 
| 
 | interconnect with a local exchange carrier. | 
| POS | Packet Over SONET. A  | 
| 
 | system through a direct fiber connection to a data switch or router. POS is a  | 
| 
 | |
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 | to pass data in its native format, without the addition of any significant level of overhead in the form | 
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 | of signaling and control information. | 
| POST | |
| 
 | powered on. | 
| Power Entry Module | See PEM. | 
| See POST. | |
| PPP | |
| 
 | and asynchronous circuits. | 
| 
 | Cisco uBR10012 Universal Broadband Router Hardware Installation Guide | 
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