Digi TransPort, Руководство пользователя

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Configure Advanced interfaces settings
Digi TransPort User Guide 287
Configure Advanced interfaces settings
The Configuration > Network > Interfaces > Advanced menu has the following sub-menu
options:
• External Modems
• PPP Mappings
• PPP
n
Point-to-Point Protocol (PPP) is a standard protocol for transporting data from point to multipoint
networks (such as IP) across point-to-point links (such as a serial or ISDN connection). This
functionality is essential for dial-up Internet access.
As data is transferred across IP networks in synchronous format, the router supports
asynchronous to synchronous PPP conversion. This allows asynchronous terminals connected to
the routers to communicate with remote synchronous PPP devices. Normally, this is carried out
using a single ISDN B-channel so that data can be transferred at speeds up to 64kbps. This is
known as ASYNC to SYNC PPP operation and is supported as standard by most terminal adapters.
To use ASYNC to SYNC PPP operation all that is necessary is to ensure that the PPP protocol is
bound to the ASY port to which the terminal or PC is connected. (see Configuration > Network >
Interfaces > Serial ).
Note In order to use ASYNC to SYNC PPP the attached terminal must also support PPP
(Windows dial-up networking supports PPP).
In addition to ASYNC to SYNC operation (where the router only converts the PPP from one form
to another) the router can initiate its own PPP sessions. This is used for example when:
The router is configured as a router to connect an Ethernet network to the Internet via ISDN or W-
WAN.
The router is answering an incoming ISDN call with PPP either for remote management or
remote access to the Ethernet network to which the router is connected.
The router is accessed locally through the serial port for configuration purposes by setting up a
Windows Dial-Up-Networking connection to the phone number 123 .
Note With the exception of MLPPP the parameters in this section are only relevant when the
router is generating the PPP, such as they are NOT relevant for ASYNC to SYNC PPP
operation.
The router also supports Multi-link PPP (MLPPP). MLPPP uses both ISDN B-channels
simultaneously (and two PPP instances), to provide data transfer speeds up to 128Kbps for
applications such as email or establishing a point-to-point connection between two routers.