Data Compression; Security On Isdn - Bay Networks NauticaRS Reference Manual

NauticaRS 5.5R Reference Guide

Data Compression

Security on ISDN

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Some models in the Nautica series have both ISDN and leased
line connections to allow users to test network utilization in real
time over ISDN before committing to leased circuits. As traffic
patterns change, leased circuits or ISDN can also be added or
removed at any site without making equipment redundant.
Data compression, based on an optional Lempel-Ziv algorithm,
gives typical compression ratios of between 2:1 and 8:1,
increasing the effective throughput to 512 Kb/s across a single
64 Kb/s ISDN link. This reduces ISDN call costs, and in
combination with Multilink can provide up to 2 Mb/s of
throughput between routers. Data compression is automatically
negotiated at link startup, depending on the parameters set at both
ends.
Security is important when using ISDN because it is a public
network. Nautica routers have several features designed to
maintain security and prevent unauthorized access:
• Calling Line Identification (CLI or Caller ID) ensures that
incoming ISDN calling numbers are checked before access is
granted.
• Secure Unit is a mechanism that restricts automatic path
creation to other units and allows only previously defined
paths to be established.
• The initial link establishment between units can be protected
by use of a secure key algorithm to prevent unauthorized
access.
• Where Point-to-Point (PPP) is used as the link protocol for
connecting to third-party routers, Password Authentication
Protocol (PAP) can be used. Nautica routers also support
Challenge Handshake Authentication Protocol (CHAP),
which gives improved security because passwords are never
sent across the link.
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