TCP and WAN issue
tme at multicasttech.com
Wed Mar 28 12:34:04 UTC 2007
On Mar 28, 2007, at 5:12 AM, Andre Oppermann wrote:
> Marshall Eubanks wrote:
>> You might want to look at this classic by Stanislav Shalunov
> The description on this website is very good.
> Disclaimer: I'm a FreeBSD TCP/IP network stack kernel hacker.
> To quickly sum up the facts and to dispell some misinformation:
> - TCP is limited the delay bandwidth product and the socket buffer
> - for a T3 with 70ms your socket buffer on both endss should be
> - TCP is also limited by the round trip time (RTT).
> - if your application is working in a request/reply model no
> amount of
> bandwidth will make a difference. The performance is then entirely
> dominated by the RTT. The only solution would be to run multiple
> sessions in parallel to fill the available bandwidth.
> - Jumbo Frames have definately zero impact on your case as they don't
> change any of the limiting parameters and don't make TCP go faster.
> There are certain very high-speed and LAN (<5ms) case where it may
> make a difference but not here.
> - Your problem is not machine or network speed, only tuning.
> Change these settings on both ends and reboot once to get better
> "SackOpts"=dword:0x1 (enable SACK)
> "TcpWindowSize"=dword:0x7D000 (512000 Bytes)
> "Tcp1323Opts"=dword:0x3 (enable window scaling and timestamps)
> "GlobalMaxTcpWindowSize"=dword:0x7D000 (512000 Bytes)
And, of course, if you have Ethernet duplex or other mismatch issues
anywhere along the
path, performance will be bad.
>> On Mar 27, 2007, at 4:26 PM, Philip Lavine wrote:
>>> To all,
>>> I have an east coast and west coast data center connected with a
>>> DS3. I am running into issues with streaming data via TCP and
>>> was wondering besides hardware acceleration, is there any
>>> options at increasing throughput and maximizing the bandwidth?
>>> How can I overcome the TCP stack limitations inherent in Windows
>>> (registry tweaks seem to not functions too well)?
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