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Questions tagged [tcp-window-scaling]

TCP congestion control depends on window scaling

TCP congestion control depends on window scaling. The sender can transmit several packets without waiting for acks, and the window size determines the number of transmitted bytes that can be outstanding (not yet ack'd). The receiver can reduce the window size as a means of throttling the sender. A TCP flow control algorithm can increase the window size when no congestion is occurring.

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Receiver limits TCP window size to 64,512

Facts (please identify any false statements): I have a 100 Mbps connection between two sites that are 80 ms apart This is a long fat connection that could benefit from a large TCP window size perhaps up to 100 Mbps * 0.08 sec = 1,000,000 bytes Both…
Chris Stankevitz
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TCP Window Scaling for Satellite Connections

A satellite connection generally has a RTT around 500ms. Connections generally suffer sub-optimal transfer speeds, in spite of large amounts of bandwidth because TCP acknowledgements take too long to arrive. My understanding is that a good way to…
directedition
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Dropped packets, on recieve only, Server 2008 only, and network speed is 100mb/s

I have a really strange one. I have packet loss with Excessive 'TCP Dup ACK' & 'TCP Fast Retransmission' when I download files (and only download) from two different Windows 2008 servers. Upload speed is fine. This ONLY occurs if the client…
Porch
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Cisco ASA 5505, tcp window scaling (rfc1323)

I have a very odd issue with our cisco firewall, If on our osx machines we run the following to disable window scaling support: sudo sysctl -w net.inet.tcp.rfc1323=0 We see near 40% improvement in download speeds (tested using varying linux iso…
Oneiroi
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better alternative for tcp_syncookies in linux

In an effort to prevent DDOS attacks I followed suggestions to leave /proc/sys/net/ipv4/tcp_syncookies value set to 1 in my linux box to enable TCP syncookies. However, when I look at this URL:…
user286228
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How to edit TCP window size from iptables?

There is TCPMSS target to edit MSS value of connections (including forwarded). How to edit window size (for example, cap to some maximum value) by iptables rule? Expecting something like iptables -t mangle -A OUTPUT -p tcp --dport 1234 -j TCPWINDOW…
Vi.
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On a TCP connection, can the recipient control the TCP window size that the sender uses?

The TCP window size is the amount of data that the sender will send before waiting for a TCP ack. Does the receiver have a way to control this (e.g., as part of the TCP handshake), or is it only the sender who can control?
jhourback
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TCP Window Scaling Not Working Between Windows 10 and Linux Server

We are having some issues with several clients running Windows 10 downloading files from our HTTP file delivery server. We can't reproduce the error on our end but notice that TCP window scaling is not "ramping up" and throughput between the Linux…
Ted Wilmont
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How to change tcp's window size?

I've tried changing the tcp's window size by modifying net.ipv4.tcp_wmem and net.ipv4.tcp_rmem values, however the changes which I make have no effect on actual window size which I can check using a wireshark. I tried to do that on 2 different…
rfire
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Why can't I reliably send or recieve data over TCP after moving servers?

I am currently dealing with a networking problem on high latency (100-400ms) Internet links. I run a Minecraft network, and I recently moved it to a separate datacenter to get a server with a better CPU and more ram. The users of this server are…
john01dav
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View / tweak TCP window size settings on Ubuntu 1804

I have a typical long fat network -- clients connect to servers with large bandwidth but also significant latency due to geographic distances of 30ms to 100ms, transferring large files. I've noticed the classic decay of throughput ~ which decays as…
David Simic
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windows server 2012 tcp window not scaling

I've got 2 windows 2012 servers that limit connection speed to anywhere from 1-3mBps and it seems to be related to tcp window scaling. Both servers have these settings TCP Global Parameters ---------------------------------------------- …
user3930869
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IIS on Server 2012 R2 serving very slowly to remote clients

We've been trying to debug very slow transfer rates for remote clients hitting our web server (IIS on 2k12 R2). The RTT to the client is about 150ms, and we're struggling to get more than about 500kbps out of our 100Mbps link. The client can…
Adrien
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FreeBSD slow transfers - RFC 1323 scaling issue?

I think I may be having an issue with window scaling (RFC 1323) and am hoping that someone can enlighten me on what's going on. Server: FreeBSD 9, apache22, serving a static 100MB zip file. 192.168.18.30 Client: Mac OS X 10.6, Firefox…
Trey
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How to adjust TCP Window Size?

I asked a similar question before, but I believe I was not clear with the details. I'm basically having some problems with my server related to high latency between the server and the clients due to the geographical distance. And making a research,…
Efe Zaladin
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