Compression; Tcp Window Size/Scaling Performance Tuning; Modifying The Window Size And Scaling Factor - HP MPX200 User Manual

connections utilized through the network are not set to Jumbo, performance can degrade
significantly.
In addition to support for Jumbo frames, you can select other and configure the MTU size
between 1000 and 9000 bytes.
NOTE:

Compression

The MPX200 integrates a software compression option. This option can be set to disable,
enable, or auto. When set to auto, the MPX200 continually assesses data compressibility and
automatically enables or disables compression based on data compressibility. The default setting
for software compression is disable for new installations. If upgrading from an version of firmware
earlier than v3.2.0.1, the existing setting is maintained (either enable or disable).
NOTE: The auto compression mode setting is available with MPX200 firmware version 3.2.0.1
or later.
Use the disable setting if you know that the data being transferred over FCIP is not
compressible.
Use the disable setting when using a high speed WAN link (622 Mb/s OC- 1 2 up to 1
Gb/s) in a configuration with simultaneous FCIP and iSCSI functions operating on the same
MPX200 blade.
Use the enable setting if you know that the data being transferred over FCIP is compressible.
Use the auto setting if you are unsure of data compressibility.
NOTE:
parameter, matched to the guaranteed available bandwidth (QoS) of the WAN link, based
on the number of routes. See
you use the auto setting if the available bandwidth per route is inconsistent or unpredictable.

TCP window size/scaling performance tuning

The MPX200 FCIP performance is maximized when properly configured. Knowing the RTT (distance)
between MPX200 Multifunction Routers and the WAN dedicated or guaranteed bandwidth allows
the gateways to be tuned for optimal performance. See
factor" (page

Modifying the window size and scaling factor

The MPX200 window size can be set to a maximum of 32 KB. The scaling factor is used as a
multiplier to increase the window size above 32 KB. Modify the window size and scaling factor
in the MPX200 Multifunction Router pairs based on the WAN RTT and link speed. To determine
the appropriate window size setting and scaling factor, use the pre-populated tables or the following
formula. In version 3.4.0.0 and above the TCP Window size and Window scaling factor were
combined into a single parameter that reflects the true TCP Window size versus the three parameters
used in previous versions.
NOTE: Use the MPX200 CLI command ping to determine the RTT and select only the default
(~56) packet size for this test. For troubleshooting link issues, always use the maximum packet
size.
If the recommended TCP window size and scale factor for a given RTT and WAN link speed is
not shown in
link rate (Kb/s) x (1 byte/8 bits)) = minimum window size (MWS).
Jumbo frames are not supported for use with HP Continuous Access.
All mode settings require the proper setting of the MPX200 bandwidth per route
"Bandwidth per route" (page
123).
Table 22 (page 124) through
122). HP does not recommend that
"Modifying the window size and scaling
Table 28 (page 126), use the formula: (RTT (ms) x
IP performance tuning 123