HP 600 Series, Services And Applications

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3. For all HP routers:
When running slow WAN links (9.6 Kbit/s to 19.2 Kbit/s) it is
usually beneficial to run compression.
Throughput will generally be improved when running compression
on very slow links, so it is a good idea to turn on compression for
these links except where noted below.
In IPX environments, run compression only under the
following conditions:
File server : Must be running the packet burst module,
PBURST.NLM version 2.02 or greater. Also, the following
parameter must be set in the STARTUP.NCF file:
set maximum physical receive packet size = 1518
Client station : Must be running VLM 1.1 or greater, and the
following parameters are recommended for the NET.CFG file:
MINIMUM TIME TO NET = 0 (default)
PBURST READ WINDOW SIZE = 16 (default)
PBURST WRITE WINDOW SIZE = 10 (default)
Higher values were used for the window sizes, but there was little
performance difference. Also, increasing the window size could
result in many more retransmissions because if a packet is lost, all
packets in the window must be retransmitted, not just the one packet
that was lost.
The reason for the burst mode requirement in Novell networks is
that the standard NCP (NetWare Core Protocol) uses a method that
requires the acknowledgment of every packet that is transmitted.
Additionally, standard Novell file servers acting as IPX routers
require that data packets be no larger than 512 bytes. Considering
that the IEEE 802.3/Ethernet standards allow for a maximum packet
size of 1514 bytes (and 4500 bytes in token ring networks!), one can
see that even in non-compression implementations, valuable band-
width is being wasted. It is for this reason that Novell implemented
PBURST.NLM. PBURST not only allows for larger packets, but also
allows bursts of up to 64 kilobytes of data to be sent before an
acknowledgment is required. Performance testing has shown that
without packet burst mode
and large packets , compression is not
useful, and may actually decrease performance.
Data Compression for WAN Links
WAN link planning
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