Transition Networks, Inc.
S4224 Web User Guide
33595 Rev. C
Page 657 of 669
the packets. Ping was created to verify whether a specific computer on a network or the Internet exists and is
connected.
Ping
uses Internet Control Message Protocol (ICMP) packets. The PING Request is the packet
from the origin computer, and the PING Reply is the packet response from the target.
Pipe Model
One of three different models defined in RFC 3270, and which define, for example, inheritance of TTL and
EXP/TC in the label stack during push and pop. TTL inheritance is defined in IETF RFC 4343. See also "Short
Pipe Model" and "Uniform Model".
PoE
PoE (Power Over Ethernet) is used to transmit electrical power, to remote devices over standard Ethernet
cable. It could for example be used for powering IP telephones, wireless LAN access points and other
equipment, where it would be difficult or expensive to connect the equipment to main power supply.
Policer
A policer can limit the bandwidth of received frames. It is located in front of the ingress queue.
Preferred address
In IPv6, an address assigned to an interface whose use by upper layer protocols is unrestricted. Preferred
addresses may be used as the source (or destination) address of packets sent from (or to) the interface.
Preferred lifetime
In IPv6, the length of time that a valid address is preferred (i.e., the time until deprecation). When the preferred
lifetime expires, the address becomes deprecated.
Private VLAN
In a
private VLAN, communication between ports in that private VLAN is not permitted. A VLAN can be
configured as a private VLAN (PVLAN).
PSC
Per Hop Behavior Scheduling Class; IETF RFC 3140 defines a binary encoding to uniquely identify PHBs
and/or sets of PHBs in protocol messages for cases where it is necessary or desirable to identify a set of PHBs
in a protocol message, such as a message negotiating bandwidth management or path selection, especially
when such messages pass between management domains.
PTP
PTP (Precision Time Protocol) is a network protocol for synchronizing the clocks of computer systems.
Q
QCE
QCE (QoS Control Entry) describes QoS class associated with a particular QCE ID. There are six QCE frame
types: Ethernet Type, VLAN, UDP/TCP Port, DSCP, TOS, and Tag Priority. Frames can be classified by one of
four different QoS classes: "Low", "Normal", "Medium", and "High" for individual application.