Duplicate ACKs

arunachalam · 11-07-2005, 08:47 AM

Hi,

"The purpose of this duplicate ACK is to let the other end know that a segment was received out of order, and to tell it what sequence number is expected" - but even if the sender tcp sends the correct expected seq and ack, the receiver is sending "Duplicate ACK".

Please explain me why is this happening.

Regards,
Arunachalam.

nx5000 · 11-07-2005, 09:21 AM

In general it can mean that your connection has a low level problem, eg for wifi : you are too far , for wired network, you are over the limit given by ethernet standard.
If its on a broadband link, maybe a router is loosing some packets due to heavy load.

You are loosing TCP segments.

You can have a look at this:
http://rfc.dotsrc.org/rfc/rfc2581.html

arunachalam · 11-07-2005, 10:57 AM

Hi,
The medium i am using is ethernet in a LAN.
And there is no packet loss. I verified in the ethereal tool.

How's that possible?

Regards,
Arunachalam.

nx5000 · 11-07-2005, 11:28 AM

Are you mixing Full and Half Duplex?