How do I alter TCP timeouts (SRTT & RTO)

[Guest]

Hi

Can anyone please help?! : )

I am working with a Win2000 IP network over a HF radio system with high
latencies (ping = 35 secs). Putting the jokes aside of 'why bother'!, we
occasionally get a TCP timeout occurring. I know this is because the reply
takes longer than the TcpTimeout setting. The MS info on this is at

http://www.microsoft.com/resources/...s/2000/server/reskit/en-us/regentry/58802.asp

I have changed the TcpInitialRtt value in the registry but this is an
initial value to start the Smoothed RTT (SRTT) which is then dynamically set
using a given formula as discussed in

http://www.informit.com/articles/article.asp?p=130716&seqNum=4&rl=1

SRTT is calculated by values such as [alp], [beta]. Retransmission TimeOut
(RTO)
is then calculated from SRTT and also has values such as upper and lower
bounds (UBOUND, LBOUND). I have done a lot of searching and can find lots of
information on what I have discussed above, but nothing about where I can set
the values above. I assume these are set in the registry like TcpInitialRtt
etc are.

cheers David
sunny England

 

[Dave Patrick]

Something here may help.

http://support.microsoft.com/?id=120642

--

Regards,

Dave Patrick ....Please no email replies - reply in newsgroup.
Microsoft Certified Professional
Microsoft MVP [Windows]
http://www.microsoft.com/protect

:
| Hi
|
| Can anyone please help?! : )
|
| I am working with a Win2000 IP network over a HF radio system with high
| latencies (ping = 35 secs). Putting the jokes aside of 'why bother'!, we
| occasionally get a TCP timeout occurring. I know this is because the reply
| takes longer than the TcpTimeout setting. The MS info on this is at
|
|
http://www.microsoft.com/resources/...s/2000/server/reskit/en-us/regentry/58802.asp
|
| I have changed the TcpInitialRtt value in the registry but this is an
| initial value to start the Smoothed RTT (SRTT) which is then dynamically
set
| using a given formula as discussed in
|
| http://www.informit.com/articles/article.asp?p=130716&seqNum=4&rl=1
|
| SRTT is calculated by values such as [alp], [beta]. Retransmission TimeOut
| (RTO)
| is then calculated from SRTT and also has values such as upper and lower
| bounds (UBOUND, LBOUND). I have done a lot of searching and can find lots
of
| information on what I have discussed above, but nothing about where I can
set
| the values above. I assume these are set in the registry like
TcpInitialRtt
| etc are.
|
| cheers David
| sunny England

 

[Guest]

Thanks Dave

I have come across most of these settings in the past few days - not that
I'll pretend to know what they all mean! but none of them appear to be to
alter the values I am after. Settings like TcpInitialRtt are not in this link
either but is an actual registry setting.

Discussions with Dan Seur on the W2k Networking forum has confirmed my
suspicions that MS have not implemented full RFC-793 'adjustability' while,
maybe *nix may have. Maybe thats a good thing to protect us from ourselves?!
but a bit frustrating when you know what you need to change but cant!

cheers again David