HP 200 Series Services And Applications page 191

WAN link planning
When planning a wide area network, it may be useful to know what link
speeds are needed given an estimated WAN utilization level. For example, if
you know you will utilize approximately 84 Kbit/s of WAN bandwidth, then
what link speed should you purchase for running compression? You can use
the following formula to determine the desired link speed:
(throughput) / 1.5 = (link speed)
Therefore, given a desired throughput of 84 Kbit/s, you may purchase a WAN
service with a link speed equal to (84) / (1.5), or 56 Kbit/s.
2. Fixed-port routers ( HP Router ER/TR/SR/FR/PR/FR/PR/TFR
etc.)
Compression should not be run on WAN links with speeds
greater than 64 Kbit/s.
As stated above, in the Router 650 case, if compression is run on
higher speed links, the throughput will likely not increase beyond
that of a 64 Kbit/s link due to the required CPU bandwidth to
compress and decompress the data. The 64 Kbit/s limit is imposed
on the these routers, instead of the 256 Kbit/s limit of the Router 650,
because the architecture of fixed-port routers is such that there is
one processor for both routing and compression; thus, CPU
demands are greater.
On an HP Router SR, no more than 2 WAN links should be
configured for compression and the third WAN link should be
configured for speeds no higher than 9.6 Kbit/s.
Again, the software-based compression algorithm will prevent higher
throughputs from being achieved. However, if the two links config-
ured for compression are not completely saturated, then it will be
entirely possible to get more than 9.6 Kbit/s throughput on the third
link.
Data Compression for WAN Links
WAN link planning
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