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Questions tagged [tcp-slow-start]

12 questions
10
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2 answers

Linux Slow Start: Changing ip route does not have any effect on initial window

I changed the tcp initial window in my machine to 10 as shown below [user@site etc]$ sudo ip route change default via 17.255.209.1 dev eth0 proto static initcwnd 10 And changed tcp_slow_start_after_idle as shown below [user@site etc]$ sudo…
Quintin Par
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9
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2 answers

What are possible downsides to setting a (very) large initcwnd for high-bandwidth connections?

I have been experimenting with the TCP parameters in Linux (with a 3.5 kernel). Basically concerning this connection: Server: Gigabit uplink in datacenter, actual bandwidth (due to sharing uplinks) is around 70 MB/s when tested from another…
Tomas
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7
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4 answers

linux initcwnd and initrwnd via /etc/sysctl.conf

Folks, As we know, the 3.x kernels have higher TCP default connection values, such as initcwnd and initrwnd. For 2.x friends, is there a way to set these in /etc/sysctl.conf instead of the ip route way? Instead of the following: sudo ip route…
CMag
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7
votes
2 answers

Clarification about Linux TCP window size and delays

I have delays when sending data through a TCP channel I am not able to understand. The link is a 1Gb link with a end to end latency of roughly 40ms. In my current setup, latency (the time from one message to go from the sender user space to the…
jlafaye
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4
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2 answers

Increasing tcp slow start Initial Window in linux 3.0 kernel

I was checking the IW for my site and realized that its 4. [user~]$ sudo tcpdump -n -i any 'tcp[tcpflags] & (tcp-syn|tcp-ack) == tcp-syn and port 80' tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on any,…
Quintin Par
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2
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1 answer

Finding out TCP Initial Window segment size in linux

I run Centos [user ~]$ cat /etc/redhat-release CentOS release 6.2 (Final) With kernel 3.0.4-x86_64-linode21 How do I check the TCP initial window size in my OS? I need to verify that the IW is 10.
Quintin Par
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0
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1 answer

Upgrading Web Application's Systems' Kernels for IW10 & other related improvements - upgrade all machines? LB first? Most important?

Stackers - We're making the push to upgrade the systems for our web app to take advantage of the various TCP improvements becoming more readily available (e.g. http://googlecode.blogspot.com/2012/01/lets-make-tcp-faster.html ) We've got the kernel…
jstats
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0
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1 answer

windows 8 taking long time to open Mac server share

I have a machine running windows 8 on a Mac server environment. When mounting or accessing a small/empty shared folder on the network the computer connects fine. When accessing another shared folder on the network it doesn't seem to load (I left…
Nick
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0
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1 answer

Linux unfriendly IIS/ASP.NET :-) : Quick download on windows but slow on linux

This particular web site (gops.tay.be) serves objects quick if I try to request the page using windows, but I get them very slow if trying using linux. There is no difference if I use browser or curl: Windows: C:\curl>curl…
user174704
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1 answer

Long TCP/IP Connect time (20-40s) with Apache 2.4, mod_proxy_ajp, Tomcat 7.0.39 running on Windows Server 2008 R2

The initial connection to an Apache HTTP Server is taking a very long time (20-40s), but the subsequent connection is very fast (<50ms). I use Apache HTTP Server as a load balancer using mod_proxy_ajp in front of four clustered Tomcat servers. I…
Yusuf S
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0
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0 answers

How to disable `tcp_slow_start_after_idle` only for selected interface or route?

I'm running a server with multiple network interfaces (some are VLAN interfaces). Some of the connections are in local network with highly bursty traffic over TCP meaning they suffer at lot from having tcp_slow_start_after_idle=1. On the other hand,…
Mikko Rantalainen
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1 answer

Why do network speeds gradually increase for big downloads over HTTP?

I've had certain instances of downloading from websites (right now I'm downloading the latest version of Ubuntu from virginmedia.com) where the speed of the download gradually increases (increasing by a few kilobytes in speed per second). Is there…
Zack Zatkin-Gold
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