tcp highspeed enable
Enables the HS-TCP feature, which provides acceleration and high throughput for high bandwidth networks where the WAN pipe is large but latency is high.
Syntax
[no] tcp highspeed enable
Parameters
None
Usage
HS-TCP 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 HS-TCP.
You need to carefully evaluate whether HS-TCP will benefit your network environment. When enabling HS-TCP in high-available-bandwidth environments, Riverbed suggests that you test the throughput against various SDR and LZ settings. If you have an Optical Carrier-3 line or faster, turning off SDR makes sense and allows HS‑TCP to reach its full potential.
To configure HS-TCP
• enable HS-TCP.
• disable LZ compression and SDR in the optimization policies if your WAN link capacity is 100 Mbps.
• enable in-path support.
• increase the WAN buffers to twice BDP or 10 MB. You can calculate the BDP WAN buffer size.
• increase the LAN buffers to 1 MB.
To calculate the BDP WAN buffer size
Bandwidth = 155000000 Mbps
Delay = 100 ms
For a link of 155 Mbps and 100 ms round-trip delay, the WAN buffers should be set to
2 * 155000000 * 0.1 / 8 = 3875000
To calculate the BDP for a link
bandwidth * delay / 8 / MTU = X
If X is greater than default (256 KB), enable HS-TCP with the correct buffer size.
The no command option disables HS-TCP.
Example
amnesiac (config) # tcp highspeed enable
amnesiac (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
amnesiac (config) # in-path enable
amnesiac (config) # protocol connection lan receive buf-size 1000000
amnesiac (config) # protocol connection lan send buf-size 1000000
amnesiac (config) # protocol connection wan receive def-buf-size 3875000
amnesiac (config) # protocol connection wan send def-buf-size 3875000
Product
SteelHead CX, SteelHead EX, SteelHead-v, SteelHead-c
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