Glossary
GL-8
Cisco 10000 Series Router Software Configuration Guide
OL-2226-23
point-to-point
subinterface
With point-to-point subinterfaces, each pair of routers has its own subnet. If you put the PVC on a
point-to-point subinterface, the router assumes that there is only one point-to-point PVC configured on
the subinterface. Therefore, any IP packets with a destination IP address in the same subnet are
forwarded on this VC. This is the simplest way to configure the mapping and is, therefore, the
recommended method.
PPP
Point-to-Point Protocol. The successor to SLIP, PPP provides router-to-router and host-to-network
connections over both synchronous and asynchronous circuits.
PPPoA
PPP over ATM. Enables a high-capacity central site router with an Asynchronous Transfer Mode
(ATM) interface to terminate multiple remote PPP connections.
PPPoE
PPP over Ethernet. Allows a PPP session to be initiated on a simple bridging Ethernet connected client.
Refers to a signaling protocol defined within PPPoE as well as the encapsulation method. See also
RFC 2516.
PPPoEoA
PPP over Ethernet over ATM. Allows tunneling and termination of PPP sessions over Ethernet links
and allows for Ethernet PPP connections over ATM links.
PPPoEoE
PPP over Ethernet over on Ethernet. Allows tunneling and termination of PPP sessions over Ethernet
links and allows for Ethernet PPP connections over Ethernet links.
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
Priority Queuing.
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
Permanent virtual circuit or connection. Virtual circuit that is permanently established. PVCs save
bandwidth associated with circuit establishment and tear down in situations where certain virtual
circuits must exist all the time. In ATM terminology, called a permanent virtual connection. Compare
with SVC. See also virtual circuit (VC).
PVP
Permanent virtual path. Virtual path that consists of PVCs.
PXF
Parallel Express Forwarding. Also referred to as
fast forwarder
. A pipelined, multiprocessor parallel
packet engine, optimized for fast packet forwarding.
Q
QoS
Quality of service. Cisco IOS QoS technology lets complex networks control and predictably service a
variety of networked applications and traffic types.