AAA --authentication, authorization, and accounting.
NACK --negative acknowledgement message.
POD --packet of disconnect. An access_reject packet sent from a RADIUS server to the gateway in order to disconnect a call which has been connected already. After validation of the packet, the gateway disconnects the user. The packet contains the information to disconnect the call.
POD server--a Cisco gateway configured to accept and process POD requests from a RADIUS authentication/authorization agent.
RADIUS --Remote Authentication Dial-In User Service. An authentication and accounting system used by many Internet service providers.
UDP --User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery, requiring that error processing and retransmission be handled by other protocols. UDP is defined in RFC 768.
VoIP-- voice over IP. The ability to carry normal telephony-style voice over an IP-based Internet with POTS-like functionality, reliability, and voice quality. VoIP is a blanket term that generally refers to the Cisco standards-based (for example, H.323) approach to IP voice traffic.
VSA --vendor-specific attribute.