Kitz Forum

Broadband Related => ADSL Issues => Topic started by: hake on October 06, 2009, 06:29:10 PM

Title: Router or other congestion in the evening?
Post by: hake on October 06, 2009, 06:29:10 PM

I ran the dslreports.com Tweaks tool at 1820 hours this evening and wondered if someone would cast her/his eyes over the image of the results that I have uploaded to this forum.  It shows that a fair proportion of packets have had to be retransmitted.  There are almost no retransmits during the working day, especially during the morning when transfer efficiency is usually 99 to 100%.

I imagine that the retransmits are due to router congestion and the consequent dropping of packets.  Could this be the case?

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Title: Re: Router or other congestion in the evening?
Post by: orainsear on October 06, 2009, 07:22:34 PM

Could well be congestion.

Have you tried a pathping to a server somewhere to see if you can pin down where the packet loss is occuring?

Your MTU value appears to be quite low - 1390?  Have you optimised this properly?

Title: Re: Router or other congestion in the evening?
Post by: hake on October 06, 2009, 08:27:53 PM

I quite agree.  It's a strange thing that the dslreports.com Tweak tool turns my MTU of 1430 (all my hosts and router are set to this value) into 1390.  I'm mystified but it's always done this.  Anyway, as long as it doesn't increase the MTU, it won't cause packet fragmentation so no harm done.

You seem to share my view that congestion is responsible for packet loss.  What else could it be?

I am going to use Tweak during the Ukraine v England match to try to determine what effect the enormous video stream traffic might be having on my internet experience at that time.

Title: Re: Router or other congestion in the evening?
Post by: kitz on October 07, 2009, 11:31:17 AM

>> Tweak tool turns my MTU of 1430 (all my hosts and router are set to this value) into 1390.  I'm mystified but it's always done this.

hake sorry - cant remember but are you using a Voyager 21xx by any chance?

Title: Re: Router or other congestion in the evening?
Post by: hake on October 07, 2009, 01:54:35 PM

Hi Kitz.  I use a SmartAX MT882.

I typically have real downstream speed of 3.9Mbps.  Is this consistent with IP profile of 4.5Mbps?

Title: Re: Router or other congestion in the evening?
Post by: kitz on October 07, 2009, 04:53:42 PM

>> I use a SmartAX MT882.

I only wondered because I used to see the same thing with MTU reporting when using a voyager 2100... in that some sites would report it lower for some reason.

>> I typically have real downstream speed of 3.9Mbps.  Is this consistent with IP profile of 4.5Mbps?

Its possibly about right.. although it is a bit on the low side tbh.  I'd expect somewhere more around 4.2 ish.  It can depend on where you download from and how many threads there are on the go.  There is 'supposed' to be an inbuilt tollerance between the IPprofile and the setting put on the bRAS which allows for ATM overheads.

Title: Re: Router or other congestion in the evening?
Post by: orainsear on October 07, 2009, 06:15:13 PM

You could try temporarily altering the router and OS MTU values to see if this has any affect on the DSLReports results.

Also have you got another router that you could try?

Does your ISP have a preferred MTU value?

Title: Re: Router or other congestion in the evening?
Post by: hake on October 08, 2009, 09:45:42 AM

Thanks.  1430 is the largest MTU value that works best with PlusNet.   Kitz concurs with this and recommends that value for PlusNet users.  TCPOptimizer software confirms this.