Operation Manual

Introduction to NetWare MultiProtocol Router for ISDN 3.1 29
Watch Your ISDN Links
- Time Restrictions for use of specific call destinations.
♦♦ Reverse charging features
COSO (Charge One Site Only) lets you allocate the connection
charges either to your site or to the remote site or bar all outgoing
calls to a call destination.
This section is intended to sensitize network administrators respon-
sible for the WAN for the most important task that comes after the
initial set up of the WAN itself: monitoring WAN links on a regular,
daily, basis. The NetWare MultiProtocol Router for ISDN behaves
exactly the way it has been configured, and dials up remote sites
whenever a packet in a LAN is to be transferred to a remote site. In
order to keep ISDN links physically down as long as possible, it
provides a number of features - most of them have been described or
mentioned in the above sections - that can be customized according
to the networking needs and allow you to optimize your WAN
traffic.
♦♦ What can cause an ISDN link to become inefficient?
During the set up of a WAN over ISDN, but also, probably more
often, after the initial set-up, situations may appear that may very
rapidly turn formerly efficient ISDN links into a very expensive
affair. The causes for unnecessarily frequent call set-ups over ISDN
may be very diverse. It may happen that, due to incorrect configura-
tion, the router endlessly attempts to set up a connection to a remote
site, if you configured the link to be set up automatically each time
the connection fails, but did not make sure that the interface on the
remote site is really available all the time. Other likely causes for
unnecessarily frequent call set-ups over ISDN are components
added to or already installed in the local networks themselves, for
example an antivirus program installed only on one LAN, which
automatically scans all servers of the WAN at very short intervals, a
Windows for Workgroups client that has been added to one network
and is sending NetBIOS broadcasts over IPX type 20 packets at
regular, very short intervals, causing all ISDN links to all other
remote sites to be set up in order to transmit such a broadcast
packet, or an e-mail software that is configured to poll the status of
remote "post-office boxes".
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