Configuring Isdn Bri Interface; Ce1/Pri Interface; Overview - 3Com MSR 50 Series Configuration Manual

106 C 4: WAN I
HAPTER
Configuring ISDN BRI
Interface

CE1/PRI Interface

Overview

C
NTERFACE ONFIGURATION
Verify the type of the interface provided by your telecom service provider,
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whether it is ISDN BRI U or ISDN BRI S/T. Despite that ITU-T I.411 has provided
an ISDN user-network interface reference model, there are some arguments in
the position of the user-network dividing point. For this reason, some nations
adopt the U interface while some others adopt the S/T interface depending on
their needs. Therefore, you must make sure the interface type provided by your
service provider before making a router purchase decision.
Request for digital service. As ISDN can provide integrated services including
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both digital and voice, you must request for an ISDN line allowing digital call
service so that your router can make digital communications.
Select connection type, which can be a point-to-point connection or a
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point-to-multipoint connection (optional). As ISDN supports semipermanent
connection, you can adopt the ISDN leased line in the event that you adopt
ISDN only for connecting two fixed points. Otherwise, you must select a
point-to-multipoint connection.
Request for the delivery of Calling Line Identification (CLI) function (optional).
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With it, you can implement calling ID filtering on your ISDN line to reject some
users from accessing the local router and hence enhance the network security.
Follow these steps to configure an ISDN BRI interface:
To do...
Enter system view
Enter ISDN BRI interface view
Enable external loopback on the
ISDN BRI interface
ISDN BRI interfaces are used for dialup purpose. For details on ISBN BRI interface
configuration, refer to
on page 192.
In 1960s, the time division multiplexing (TDM) technology gained increasingly
wide application in the data communications system along with the introduction
of pulse code modulation (PCM) technology. So far, there exist two TDM systems
in the data communications system. One is the ITU-T recommended E1 system
that is widely adopted in Europe and P.R. China. The other is the ANSI
recommended T1 system that is widely used in North American and Japan. (The
system that Japan adopts is actually called J1. It is regarded as a T1 system due to
high similarity between them.)
A CE1/PRI interface can work in either E1 mode (also called non-channelized
mode) and CE1/PRI mode (that is, channelized mode).
A CE1/PRI interface in E1 mode equals an interface of 2 Mbps data bandwidth, on
which, no timeslots are divided. Its logic features are the same like those of a
synchronous serial interface. It supports the link layer protocols such as PPP, FR,
LAPB and X.25 and the network protocols such as IP and IPX.
Use the command...
system-view
interface bri number
loopback { b1 | b2 | both }
"DCC for Dialup ISDN BRI Line and Leased Line Connection"
Remarks
--
Required
Disabled by default