Planet IGS-10020, Руководство пользователя, Страница: 402 / 409

User’s Manual
402
PD
PD is an acronym for
P
owered
D
evice. In a PoE> system the power is delivered from a PSE ( power sourcing
equipment ) to a remote device. The remote device is called a PD.
PHY
PHY is an abbreviation for Physical Interface Transceiver and is the device that implement the Ethernet physical layer
(IEEE-802.3).
PING
ping is a program that sends a series of packets over a network or the Internet to a specific computer in order to
generate a response from that computer. The other computer responds with an acknowledgment that it received 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.
Policer
A policer can limit the bandwidth of received frames. It is located in front of the ingress queue.
POP3
POP3 is an acronym for
P
ost
O
ffice
P
rotocol version 3. It is a protocol for email clients to retrieve email messages from
a mail server.
POP3 is designed to delete mail on the server as soon as the user has downloaded it. However, some
implementations allow users or an administrator to specify that mail be saved for some period of time. POP can be
thought of as a "store-and-forward" service.
An alternative protocol is Internet Message Access Protocol (IMAP). IMAP provides the user with more capabilities for
retaining e-mail on the server and for organizing it in folders on the server. IMAP can be thought of as a remote file
server.
POP and IMAP deal with the receiving of e-mail and are not to be confused with the Simple Mail Transfer Protocol
(SMTP). You send e-mail with SMTP, and a mail handler receives it on your recipient's behalf. Then the mail is read
using POP or IMAP. IMAP4 and POP3 are the two most prevalent Internet standard protocols for e-mail retrieval.
Virtually all modern e-mail clients and servers support both.
PPPoE
PPPoE is an acronym for Point-to-Point Protocol over Ethernet.
It is a network protocol for encapsulating Point-to-Point Protocol (PPP) frames inside Ethernet frames. It is used mainly
with ADSL services where individual users connect to the ADSL transceiver (modem) over Ethernet and in plain Metro