Introduction:
A remote access is the ability to log onto a network
from a distant location and be in the proximity
of the network. Usually this terminology is associated
with a computer, a modem and remote access software
which are used to connect to the network. While
a remote control usually implies to controlling
another computer, remote access implies to the
remote computer which acts as the complete host
on the network. The remote access software dials
in directly to the network server.
Analysis: A network can be accessed
in two different ways – a remote control
connection or a remote node connection. In the
case of a remote control connection, the telephone
line becomes an extension cord for the various
parts of the computer resulting in connecting
them to a computer at the host site which can
be logged on to the network. Another key aspect
of the remote control is that it is possible with
computers which are not networked as well. Some
of the propular remote control programs are provided
by Symantec’s pcAnywhere, Microcom’s
Carbon Copy, etc. [Steinke, 1995]
Whereas in the case of the remote node connection,
a remote node server becomes predominantly a router
or the connecting point which is capable of translating
frames on the serial port to a frame layout which
the LAN can accommodate and then pass them along.
The processor should be able to route or bridge
both incoming as well as outgoing traffic as well
as it should be able to take more than 150 64kbit/sec
ISDN sessions and more than 1,000 9,600 bit/sec
uninterrupted connections to match the output
of a 10Mbit/sec Ethernet link. This whole process
doesn’t need more of infrastructure in the
form of microprocessors. Most of the remote node
servers are bought with built-in modems or with
serial ports which could be connected to external
modems or else to ISDN lines.
Such remote node or access services can be also
available through numerous hardware configurations.
The router or bridge processing are mounted on
a processor in a separate box, on a communications
server or on a separate file server which is capable
of doing communication duty. It can also be on
products which are sold as a router or bridge.
The file server should be in such a way that it
should be able to accept add-on software which
will be also performing the routing or bridging
applications. [Centralized Remote Access Authentication
with RADIUS, 2004]
Various multiple serial ports may be set into
a dedicated access box or mounted on boards that
plug in to the communications server or file server.
Internal modems are installed on plug-in boards
or set in PC card also called as PCMCIA slots.
Such remote access ports support high-speed ISDN
connections. ISDN ports may be connected on plug-in
boards for servers associated with PCs, on modular
boards for servers that are dedicated or on standalone
terminal adapter units, digital modems that are
linked to a serial port. In order to achieve the
maximum output on low-cost dial-up lines, some
ISDN access devices support inverse multiplexing
of the two 64kbit/sec B channels to provide a
throughput of 128Kbits/sec.
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