Lots of warnings/errors in Capsa free.

[Fad]

I have just been testing the free version of Capsa 7 on my home PC, and I seem to be getting quite a lot of errors and warnings:



Does this mean I have a major problem, or can they be safely ignored...or even fixed ?

Thanks.

[Spiral123]

For what its worth I have received similar results on my LAN using Capsa. I have not dug into the reasons for the results though...

[Colasoft Support]

Hi Fad,

How long did you have Capsa running before this screenshot? We see you have 485 duplicate acknowledgement, which means the first acknowledgement packets were lost and the second acknowledgement packets were sent again.

If this was just a short time number, you should check your bandwidth utilization. High utilization will cause packet lost. But if its a long time span, it should be ok. It reasonable that packets get lost in transmission.

[Fad]

The first image was taken over a short period of time, but I didn`t really make a note of how long it was or what I did online during that time.

This new image which I started this morning at 7am, I measured for approximately 45 minutes.

I checked through several websites, checked email and downloaded one 400meg file during this time.



All of the TCP Slow Response errors state: TCP Slow ACK.....
All of the TCP Duplicated Acknowledgement errors state: TCP Repeated Confirmation for Three Times.....

Does that appear to be too many errors in such a short time ?

[Colasoft Support]

Fad,

What about your utilization? Can you give a screenshot of Total Traffic in Dashboard tab?

[Fad]

OK, this is a test that lasted approximately 30 minutes:



I opened and browsed several web pages, checked email and downloaded a single 20meg file in this time (the green bar shows this).



The rest of the readings were lower than the graph bar shown in red.

I hope that`s what you wanted to see....Thanks.

[Colasoft Support]

Fad,

How do you feel about your network speed? Is it slow? You know different network has their own specifications. If your network goes smoothly, you can enlarge the threshold of this diagnosis item:

1. Click Diagnosis Settings icon on the Ribbon.
2. Find TCP Slow Response item under Transport layer.
3. Enlarge the Slow Response (ms) value on the top right. It is 150 ms by default.

If you do feel your network is slow, please export your packets in Capsa and upload them here. Then we can help you find out the problem.

[Fad]

Thanks for the reply...

My general speed is OK - I get the full speed of my connection when the sites I connect to allow it, so no problems there really.

I didn`t realise I could arbitrarily alter those threshold values, I have done that now and the warnings have certainly decreased compared to what they were before !

So I suspect there`s nothing actually wrong with my connection at all.


Capsa Free does allow me to see where any troubles may lie though, and for that reason alone it`s a very good program.

The one issue I can still see is the amount of "TCP Duplicated Acknowledgement" alarms - they still appear to be quite frequent.

I don`t understand what this means:

1. Missequence or packet lost noticed of packet sender noticed by protocol stack

But I do understand this:

2. Retransmission due to the packet lost

Are lost packets a normal thing to happen if a connection is overloaded, or data is being downloaded at high speed and there are multiple connections ?

I have over 6000 of those "alarms" recorded in just 20 minutes....should I ignore them or is there an issue with my ISP/PC/Router that needs investigating further ?

Thanks again.

[Colasoft Support]

Hi Fad,

Since you said your network speed is fine, I think it's not a big problem. I can only see your network performance is not good.

Duplicated Ack has relationship to slow response. Slow response means packets take too long to reach your machine. While some packets taking too long are discarded before it gets to your machine and the source hosts retransmit them again. So you see duplicated ack.

Now you don't give enough data for us to identify what exactly the problem is. Can you upload some sample packets?

[Fad]

I have tried to upload some sample packets, the .cscpkt file includes the packets captured over a period of approximately 5-10 minutes when I opened 4 websites and downloaded one MP3 file.

I hope that`s the correct information that you needed.

Thanks.

[Fad]

I did manage to find and test a different router and the results are the same, so I suspect my ISP is the cause of the issues I am seeing.

Thanks for the help