1. Glossary and Terms (Download PDF)

2. A usful list of Acronyms 
A B C D E F G H I J K L M N O P Q R S T U V W X   
p2p     point-to-point (or peer-to-peer)
PABX    Private Automated Branch Exchange
PBX     Private Branch Exchange
PC      Personal Computer
PHB     Per Hop Behavior
Phy     Physical layer
pkt     Packet
P-NNI   Private NNI
POTS    Plain Old Telephone Service (PSTN)
PPP     Point-to-Point Protocol
PSTN    Public Switched Telephone Network 
PVC     Permanent Virtual Channel/Circuit