Lucent Technologies PortMaster - Manual (Page 223)

14-1
Using Synchronous V.25bis Connections 14
This chapter uses an example to demonstrate how to configure the PortMaster to
connect two local area networks (LANs) via synchronous V.25bis dialing applications
such as ISDN, terminal adapters, or switched 56Kbps.
This chapter discusses the following topics:
• “Overview of Synchronous V.25bis Dial-Up Connections” on page 14-1
• “Configuration Steps for a Synchronous V.25bis Connection” on page 14-3
• “Troubleshooting a Synchronous V.25bis Connection” on page 14-13
See the PortMaster Command Line Reference for more detailed command descriptions and
instructions.
Overview of Synchronous V.25bis Dial-Up Connections
PortMaster products support dial-on-demand ISDN and switched 56Kbps connections
using synchronous ports and the PPP protocol. ISDN speeds of up to 64Kbps are possible
with an outside carrier and an external terminal adapter (TA). Speeds of up to 128Kbps
are possible if the terminal adapter supports B channel bonding. Contact your service
provider for specific information about the required terminal adapter.
Switched 56Kbps connections require an external CSU/DSU. ISDN and switched 56Kbps
connections can be initiated on an as-needed basis or they can remain active all the
time. A dial-out location must be specified in the location table for dial-out connections,
and a dial-in user must be specified in the user table for dial-in connections. PAP is
available for dial-in authentication, when a router dials in to your PortMaster. CHAP is
available for dial-in and dial-out authentication.
When connecting an asynchronous ISDN terminal adapter to an asynchronous port
using AT commands to dial, configure the PortMaster just as you would for a modem.
Refer to Chapter 15, “Using Office-to-Office Connections,” and Chapter 16, “Using
Internet Connections,” for more information.
In this configuration, keep in mind that a 115.2Kbps asynchronous DTE rate can
support only a single 64Kbps B channel, because a byte of asynchronous data requires
10 bits—including stop and start bits—for transmission, but a byte of synchronous data