HP StorageWorks Enterprise File Services WAN Accelerator 3.0.4 Command-Line Interface reference manual (AG421-96004, March 2007)
HP STORAGEWORKS EFS WAN ACCELERATOR COMMAND-LINE INTERFACE REFERENCE MANUAL 193
4 - CONFIGURATION-MODE
C
OMMANDS
tcp highspeed enable
Description Enables high-speed Transmission Control Protocol (HSTCP) which provides
acceleration and high throughput for high bandwidth networks where the WAN pipe
is large but latency is high.
The no command option disables HSTCP.
HSTCP is activated for all connections that have a Bandwidth-Delay Product (BDP)
larger than 100 packets. If you have a BDP of greater than 512 KB, and you are more
interested in filling the WAN pipe than saving bandwidth, you should consider
enabling HSTCP. HSTCP is available only on the Series 5000 and 6000.
You need to carefully evaluate whether HSTCP will benefit your network
environment. To enable HSTCP, you must disable the Lempel-Ziv (LZ) compression
and Scalable Data Referencing (SDR). With SDR your throughput will bottleneck
between 100 and 150 Mbps, which cancels out the benefit of HSTCP.
For someone with an Optical Carrier-3 line or faster, turning off SDR makes sense and
allows HSTCP 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.
Syntax [no] tcp highspeed enable
Parameters None
Usage To configure HSTCP you must:
enable HSTCP.
if your WAN link capacity is 100 Mbps, disable the Lempel-Ziv (LZ)
compression and Scalable Data Referencing (SDR) in the optimization policies.
For detailed information, see “in-path rule auto-discover” on page 112.
enable in-path support. For detailed information, see “in-path enable” on
page 106.
increase the WAN buffers to 2 Bandwidth Delay Product (BDP) or 10 MB. You
can calculate the BDP WAN buffer size. For a link of 155 Mbps and 100 ms
round-trip delay, the WAN buffers should be set to:
2 * 155 Mbps * 100 ms = 3875000 bytes
increase the LAN buffers to 1 MB.
For example:
minna (config) # tcp highspeed enable
minna (config) # in-path rule auto-discover srcaddr 0.0.0.0/0 dstaddr
0.0.0.0/0 dstport 0 optimization none vlan -1 neural-mode always rulenum
1
minna (config) # in-path enable
minna (config) # protocol connection lan receive buf-size 1000000
minna (config) # protocol connection lan send buf-size 1000000
minna (config) # protocol connection wan receive def-buf-size 3875000
minna (config) # protocol connection wan send def-buf-size 3875000