HP StorageWorks Enterprise File Services WAN Accelerator - Manual (Page 37)

HP S TORAGE W ORKS EFS WAN A CCELERATOR M ANAGEMENT C ONSOLE U SER G UIDE 37
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Enabling
HSTCP Protocol
Options
You enable the High Speed Transmission Control Protocol (HSTCP) in the
Optimization Service - Protocol: HSTCP page.
HSTCP provides acceleration and high throughput for high bandwidth networks where
the WAN pipe is large but latency is high. HSTCP is activated for all connections that
have a Bandwidth-Delay Product (BDP) larger than 100 packets. HSTCP is available
only on the HP EFS WAN Accelerator DL380-5010.
To configure HSTCP you must perform the following tasks.
To enable HSTCP
protocol support 1. Click the Setup tab to expand the Optimization Service menu.
Task Description
Enable your HSTCP license. The Optimization Service - Protocol HSTCP page only appears if you have a
HSTCP license. To obtain a license (free of charge) for your HP EFS WAN
Accelerator, contact HP technical support at
http://www.hp.com.
To enable your HSTCP license, see “Updating Your Licenses” on page 112 .
NOTE: If you want to delete the license for HSTCP, you must first disable the
HSTCP feature.)
Enable HSTCP support. For detailed information, see “To enable HSTCP protocol support” on page 37 .
Increase the WAN buffers. Increase the WAN buffers to 2 Bandwidth Delay Product (BDP) or 10 MB. For
detailed information, see
“To enable HSTCP protocol support” on page 37 .
You can calculate the BDP WAN buffer size. For example, for a link of 155
Mbps and 100 ms round-trip delay, the WAN buffers should be set to:
2 * 155 Mbps * 100 ms = 1937500 bytes
Increase the LAN buffers. Increase the LAN buffers to 1 MB. For detailed information, see “To enable
HSTCP protocol support” on page 37 .
Enable in-path support. For detailed information, see “Enabling In-Path and Out-of-Path Support” on
page 22 .
Disable the Lempel-Ziv (LZ) compression
and SDR in in-path optimization policies. For detailed information about optimization policies if your WAN link capacity
is 100 Mbps, see
“Setting In-Path Rules” on page 25 .
With SDR enabled your throughput will bottleneck between 100 and 150
Mbps, which cancels out the benefit of HSTCP. If you have an Optical Carrier-
3 line or faster, turning off SDR makes sense and allows HSTCP to reach its
full potential. For a 2 Mbps link, regardless of the amount of latency, it is better
to keep SDR enabled, because the HSTCP mechanism is typically not triggered
until you reach beyond 100 Mbps of WAN throughput.