Knowledge Base:  
My Mac OS X system is experiencing a network delay/slow down when copying files to/from a Windows system.
Last Updated 8/5/2008
The "delay" is caused by a little-known interaction between Nagle's Algorithm and Delayed ACK. For a detailed description of the problem please read:

http://www.stuartcheshire.org/papers/NagleDelayedAck/

delayed_ack=0 responds after every packet (OFF)
delayed_ack=1 always employs delayed ack, 6 packets can get 1 ack
delayed_ack=2 immediate ack after 2nd packet, 2 packets per ack  (Compatibility Mode)
delayed_ack=3 should auto detect when to employ delayed ack, 4 packets per ack.  (DEFAULT)

The problem can sometimes be fixed by changing the "delayed ack" setting.

A setting of 0 or 2 usually helps decrease the Windows copying time. These settings can be changed using the following steps:

1. Open a terminal window and use type:

vi /etc/sysctl.conf
OR use whatever editor you feel most comfortable with to create or modify: /etc/sysctl.conf

2. Enter one of the above settings and save the file. i.e.
net.inet.tcp.delayed_ack=0
OR
net.inet.tcp.delayed_ack=2

3. Reboot the system 



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