Any idea what this counter means "tcpTimRetrans"

UNIX for Advanced & Expert Users
1

I am chasing an issue where I see drop packets, in order to dig the problem further I issue netstat -s -P tcp command which shows me the stats from the tcp perspective. In that stats I see a counter which is "tcpTimRetrans" which increments along with "tcpRetransSegs".

When both of these counter increments the same time that's when my application complains that a drop packet occurs. Question is does any one knows

  1. What is "tcpTimRetrans" counter is?
  2. Any idea to what cause the "tcpRetransSegs" and "tcpTimRetrans" increments the same time?

Any help in this regards will be much appreciated.

2

tcpTimRetrans and Retransmission Segments
http://www.ietf.org/rfc/rfc2988.txt
Tips for TCP/IP monitoring and tuning to make your network sing - SunWorld - December 1996

Expanded the abbreviations and googled for them..

3

Thanks for the reply. I don't see the explanation for the counters I am looking for in the above referenced links.... Still waiting

4

You should read those links carefully... as example from the second link I've posted:

The reader will assume that if that happens, the "tcpTimRetrans" counter will increase by one at least. And also there is mentioned "segment". So since this counts for both cases, it seems both counters increase by 1 in parallel if that happens.
In short terms, there was some network / TCP/IP trouble and it tried to retransmit it's packets/segements until it were accomplished or some packets were dropped/discarded. If this count is increasing all the time when monitoring it, maybe you should check the hosts configuration or that of the hosts it is talking with.
At least this would be my guess.