User`s guide

194 XSR User’s Guide
Understanding ISDN Chapter 9
Configuring Integrated Services Digital Network (ISDN)
Security
Security is another important element of dial-up data communications, and
ISDN can support the security features of protocols running through it, as
well as its own unique mechanisms. ISDN, in addition to supporting the
standard authentication schemes of protocols riding on it (e.g. PPP's
PAP/CHAP protocols), enhances the security of dial-up connections with call
number identification.
With support for call number identification invoked by the
isdn calling-
number
command, the XSR enables the comparison of incoming callers' phone
numbers with a list of acceptable numbers. Calls can then be restricted to pre-
screened locations, a definite advantage especially when PAP/CHAP
authentication is unavailable.
Call Monitoring
Call monitoring is also an important element of the XSR’s ISDN service. Call
monitoring features are useful in terms of security, but also enable tracking of
call volume and logging of all connections so that administrators can
optimize the number of ISDN lines ordered. Given that ISDN costs are often
usage-related, this checking and recording also can prevent nasty surprises
that users might receive with the monthly phone bill. At the same time, usage
logs can provide managers with the justification required to add ISDN lines
as the need for additional bandwidth arises.
The
show interface bri, show controllers bri, and show isdn service
commands display virtual and physical line attributes including B channel
idle warnings.
The
show isdn history and show isdn active commands display Cause
Codes giving the reason why a call was disconnected. These codes are
detailed in Table 9 on page 203.