Operation Manual

30 NetWare MultiProtocol Router for ISDN 3.1 Installation and ISDN Configuration Guide
♦♦ The only way out - monitoring!
Monitoring of WANs is in general important, but it should be per-
formed especially carefully when using ISDN as the wide area
transport medium. Monitoring the WAN and all ISDN links main-
tained is extremely important and indispensable for keeping connec-
tion charges as low as possible. Only monitoring your WAN links
will give you information on the number of ISDN connections
established each day and allow to immediately detect "abnormal"
situations, i.e. extremely frequent call set-ups or an extremely long
physical up-time of an ISDN connection. Once you have detected the
critical situation, you can manage the WAN, check whether you used
all mechanisms provided by the NetWare MultiProtocol Router for
ISDN to optimize WAN traffic, sort out the node in the LAN produc-
ing the packets that cause an ISDN connection to be set up too often,
etc.
It is advisable in any case to make use of the ISDN Connection
Monitor and the ISDN Budget Manager. Cutting down an existing
ISDN link is a drastic measure, but they can be "there" also if you are
absent, and, even if you may have to sort out problems that ap-
peared due to the cut-down of the WAN connection afterwards, it
will prevent high charges from accruing at your ISDN access.
Performance-Enhancing Features
ISDN provides 64 Kbps per B channel (except for some ISDN
switches in the USA with 56 Kbps). The NetWare MultiProtocol
Router for ISDN fully uses the given bandwidth on ISDN, i.e. it
reaches a net throughput of 60 to 62 Kbps out of the theoretical rate
of 64 Kbps. In addition, it offers various features to enhance
throughput over ISDN.
♦♦ Compression
The NetWare MultiProtocol Router for ISDN implements software
data compression according to V.42bis, but compression is com-
pletely downloaded and processed on the ISDN-Controllers. Thus -
especially important when installing the router on a NetWare file
server to offer file, print and routing services - the server is not
burdened with the task of compressing and decompressing data,
which would require a considerable amount of power and could
slow down the file and print services. With compression according
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