Glossary
GL-7
Cisco 10000 Series Router Quality of Service Configuration Guide
OL-7433-09
PPPoEo802.1Q
VLAN
PPP over Ethernet over IEEE 802.1Q VLANs. Allows tunneling and termination of Ethernet PPP
sessions across VLAN links. IEEE 802.1Q encapsulation is used to interconnect a VLAN-capable
router with another VLAN-capable networking device. The packets on the 802.1Q link contain a
standard Ethernet frame and the VLAN information associated with that frame.
PPPoX
PPP over PPPoA or PPPoE or both.
PQ
See priority queuing.
priority queuing
A class queue that is given priority over other queues. The router dequeues and transmits priority queue
data before it dequeues and sends packets in other queues. Using priority queuing, delay-sensitive data
such as voice receives preferential treatment over other traffic.
PTA
PPP termination aggregation. A method of aggregating IP traffic by terminating PPP sessions and
aggregating the IP traffic into a single routing domain.
PTA-MD
PTA Multi-Domain. A method of aggregating IP traffic by terminating PPP sessions and aggregating
the IP traffic into a VPN or multiple IP routing domains.
PVC
See permanent virtual circuit or connection.
PVP
See permanent virtual path.
Q
QoS
See quality of service.
QPPB
QoS policy propagation through the Border Gateway Protocol.
quality of service
Quality of service (QoS) refers to the ability of a network to provide improved service to selected
network traffic over various underlying technologies including Frame Relay, ATM, Ethernet and
802.1 networks, SONET, and IP-routed networks. Cisco IOS QoS technology lets complex networks
control and predictably service a variety of networked applications and traffic types.
queue depth
A user-configurable limit on the number of packets that the router can place onto a queue. During
periods of high traffic, a queue fills with packets waiting for transmission. When a queue reaches its
queue depth and becomes full, by default the router drops packets until the congestion is eliminated and
the queue is no longer full.
queuing delay
Amount of time that data must wait before it can be transmitted onto a statistically multiplexed physical
circuit.
R
RADIUS
Remote Authentication Dial-In User Service (RADIUS). A client/server security protocol created by
Livingston Enterprises. Security information is stored in a central location, known as the RADIUS
server.