dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
25
share rss forum feed


bradyr
Columbia College IT
Premium
join:2008-10-27
Sonora, CA
reply to inMaryland

Re: Is this throttling?

from what i've read, comcast's congestion management practices don't do deep packet inspection (DPI). basically it doesnt care [or know] what protocols you're using/ what you are downloading.

now, of course that info could be out of date, and frankly it wouldn't surprise me if P2P traffic, for example, was a "priority target" over some other traffic, if you are on a congested node or otherwise...

also, it would be sweet to see some "evidence" of comcast's congestion management in practice...like show me some tcp graphs.. what does the data stream actually look like? ramp up then get knocked down, rinse and repeat (saw tooth) or is it ramp up, then get knocked down and stay down (capped) for the length of the download...


inMarland

@army.mil
posting TCP graphs is a very good idea... I will do so.


inMaryland

@comcast.net
reply to bradyr
Click for full size
nntp download
Click for full size
http download
nntp download graph


inMaryland

@army.mil

Re: Is this throttling? - I believe so

The tcp graphs I posted yesterday indicate the download behavior I have been seeing for over a week now. Tcp traffic through NNTP (easynews and giganews) peaks at my bandwidth limit for a very short time then bounces around from zero to something aproaching my bandwidth limit (using multi threads)... When I allow the download to continue for a long period - the download averages about 18mbps - far below my limit of 105mbps.. This has been very consistent for over a week now.. and I have been using newsgroup downloads w/o issue for years.. I am absolutely NOT seeing this issue with other downloads... I have tested using large (non nntp) files and it consistently maxes out my bandwidth for the duration of the download.

Extide

join:2000-06-11
84129
Your nntp server simple appears to not have enough bandwidth available to serve you at 105mbit. There is likely some form of shaping going on at their end, not yours, in this case.


inMaryland

@army.mil
I have been using easynews for years - they can easily fill the 105 mbps bandwidth - they have a very active support forum and there has been no complaint about throughput - I use 30 threads to download. In addition, as another test, I subscribed to a 14 day trial on giganews, using 30 threads from giganews results in the same sawtooth pattern. I am quite sure this is NOT an issue caused by the NNTP (usenet) source. To review, based on my testing during the past week, the slow download issue:

. is NOT caused by the NNTP source
. happens only with NNTP downloads (I don't use p2p ie. torrents)
. is NOT caused by my modem
. is NOT caused by my router
. is NOT related to node saturation
. is NOTcaused by my individual over use of the bandwidth
. I can recreate the results every time.. (slow (sawtooth) NNTP downloads, full throughput speed for http large file downloads)


inMaryland

@army.mil
easynews offers https ssl (port 81) downloads.. it is not optimal for my setup (can't use newsbin this way) but I will try this download method and report back... should be an interesting test.


inMaryland

@comcast.net
I tested a usenet download from easynews using their https ssl port 81 method.. it works great.. maxed out my 105mbps bandwidth for the entire 1.4G download.. it is clear to me that Comcast is now traffic shaping... probably looking at packets for NNTP and maybe other types of traffic.


JohnInSJ
Premium
join:2003-09-22
Aptos, CA
said by inMaryland :

I tested a usenet download from easynews using their https ssl port 81 method.. it works great.. maxed out my 105mbps bandwidth for the entire 1.4G download.. it is clear to me that Comcast is now traffic shaping... probably looking at packets for NNTP and maybe other types of traffic.

Well, that's hardly an exhaustive test...
--
My place : »www.schettino.us


inMaryland

@comcast.net
did not say it was an exhaustive test.. I will keep trying both methods of downloading from easynews (NNTP vs. https) for awhile (days, weeks) and report back..


jlivingood
Premium,VIP
join:2007-10-28
Philadelphia, PA
kudos:2
said by inMaryland :

did not say it was an exhaustive test.. I will keep trying both methods of downloading from easynews (NNTP vs. https) for awhile (days, weeks) and report back..

Fun experiment... What cable modem make/model and home gateway do you have? In your home gateway, any QoS settings for the upstream? If so, can you try limiting upstream bandwidth to 70% of your provisioned rate? (see »vonage.nmhoy.net/wrt54glqos.html but just try upstream limiting first before prioritizing FTP)

Jason
--
JL
Comcast


inMaryland

@army.mil
My modem is a Motorola SB6120. my router is not the issue - I get the same results by connecting the modem directly to my pc and bypassing the router. Also, I seriously doubt that my uplink channel is any where near saturated... I have an upload bandwidth of 20mbps (tested) and when I do an NNTP download my upload pipe never uses even 1mbps.. I don't use bit torrent or other p2p protocols which could saturate the upload pipe. I have not tested ftp - that would be an interesting test. And btw, my router is NOT using any QOS


JohnInSJ
Premium
join:2003-09-22
Aptos, CA
if you are 105/20 and you are maxing out your downlink for extended periods, I would not be shocked to find you are falling into the congestion management system, but there is no way to be sure of that from your end.

Have you tried several different concurrent download sources? As many as needed to fill the pipe?
--
My place : »www.schettino.us

rody_44
Premium
join:2004-02-20
Quakertown, PA
reply to inMaryland
He didnt ask if you were using QOS. He was asking you if you would mind trying it.