LinuxQuestions.org
Register a domain and help support LQ
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Networking
User Name
Password
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.

Notices

Reply
 
Search this Thread
Old 10-09-2009, 08:55 AM   #1
scheidel21
Senior Member
 
Registered: Feb 2003
Location: CT
Distribution: Debian PPC/i386/AMD64 6/7, Vista, XP , WIN7, Server 03/08
Posts: 1,287

Rep: Reputation: 97
Bandwidth issues, looking for ideas


Hi all,

I am looking for ideas and suggestions regarding a bandwidth issue I have. I started at a company in January of this year, and in May our T-1 utilization shot up to max usage all business day. Prior to this we would hit max usage a few times throughout the day, but not all day.
So basically the usage graphs look like this:

Code:
Before

   |   | | |
   |   | | |
  || | | | |
  || | | | |
__||_|_|_|_|_____

After

  _________
 |         |
 |         |
 |         |
 |         |
 |         |
_|         |_______
So anyways the data usage plateus all day long. Itpicks up in the AM and drops off as people leave. Additionally average daily utilization is double what it had been i.e. we used maybe Avg 50% of bandwidth daily, now we use 97%-99%. The rub lies in the fact that this started before we moved to a new SAP portal, so operations in January in terms of Internet usage were the same as they were in May when this started. It was not until mid June when our new Web based Vendor portal was implemented. ANd this did not have any effect on the all ready saturated T-1 line.

I worked with our T-1 provider ATT who were able to demonstrate to me that unplugging the LAN made the data stop, and really nothing else. I have worked with our router vendor to try and see what data was coming in but our Juniper SSG 140 Netscreen OS does not provide that kind of realtime monitoring.

So I have some data collection servers in place, I have implemented bandwidthD, netop, cacti, mrtg, ipband, snort, iftop, and placed a squid proxy server in place then used Active Directory policy to set all users on the proxy, with a couple exceptions I have made myself.

What has all this data told me? It looks like it is legitamite traffic, The stats colelcted by cacti and mrtg match the ATT usage stats, the firewall logs and dropped packets count from the router do not indicate any foul play. bandwidthD does not show the same amount of traffic, but does show high utilization. ipband shows me the top data users when a threshhold I set is passed for more than five minutes, The data all sems to be legitimate. Snort shows no suspicious activity that is not expalined by my activities and almost none of the activity involves external IP addresses. netop shows high usage and is relatively consistent with ATT and cacti graphs. iftop number do not match with general utilization on two second average often being 500-600 kb out of a possible 1500, it does spike from time to time, and occasionally will spike up to 9-10Mb/s for a very brief moment but then normalizes. Finally the proxy I have put that in place, and it now eats most of the bandwidth itself as it is proxying for most machines, but sites being visited etc... are normal with the highest ones being, as they should, the vendor portal sites we access. The bandwidth is still near max capacity, though just a hair less than it had been before the proxy.

I have come to the conclusion that we are just eating up the bandwidth, I mean a T-1 is not that high capacity. What exactly caused the jump I cannot pin point though. While this does not bother me so much as I have no other explanation. My co-worker who works in IT with me, who has been here longer, and is a supervisory capacity to me, will not settle for that, he wants an answer, I cannot provide hm with one, I spent weeks and weeks on this issue. Unfortnately I have no data from before the issue started, so I cannpt do a comparison to see the differences. He is positive something is wrong in that there has to be a specific reason our bandwidth maxed out all of a sudden. He will not settle for no answer as to waht that cause is. He is also a bit incredulous to the idea we have maxed out our T-1 period, to paraphrase he says that we don't use that much data on the internet.

So thank you if you have stayed to read this far my question to all of you is what should I do from here, is there really anyway to get what he wants, any ideas as to what the issue may be, other than legitamite circuit max utilization? Perhaps you have an idea of where I can look in the logs to find something I missed. I really need an answer as this is causing friction here. As I am suggesting adding a low cost, high speed DSL to the router and then routing general traffic over it and sending email, http, ftp, and VPN traffic over the T-1. He almost flat out refuses to OK the DSL with our Boss if I cannot find the cause. He all ready thinks we should dump ATT as teh T- provider because they are not doign more to assist us. Though my opinion is that there is little else they can do to assist us.

Well thank you for your time and any ideas or suggestion you may have. Sorry to drone on so long.

Alex
 
Old 10-09-2009, 10:06 AM   #2
in_texas_dallas
Member
 
Registered: Sep 2009
Location: DFW
Distribution: Debian Lenny
Posts: 38

Rep: Reputation: 17
Alex,

So logically speaking, since you say nothing has changed [should have changed] with your company's actual usages, it would seem that something else *external* changed. Since you have done comprehensive testing on the traffic <After>, I would say the only difference in that is perhaps measuring.

For example, you are comparing it to before and the difference there is what is causing the consternation. How can you be guaranteed that the data for <Before> is accurate OR an apples to apples comparison.

Assuming that, in reality, your traffic usage HAS NOT changed, sometimes the simplest solutions are the right ones... My first idea is that your original "Before" chart was just plain old wrong. As in: it wasn't counting traffic accurately [the same as the current]. If you say bandwidth usage hasn't actually changed, perhaps it really hasn't.

Also, it didn't seem expressly clear... Is it possible to verify if some or all of that traffic is *local* "lan" traffic, aka NOT traffic that actually reaches the internet... if that makes any sense. Printers have traffic, file sharing, messaging systems... Your network could have a plethora of devices/software that communicate back and forth locally only. If you do any sort of computer monitoring, that should run on the local "LAN"...etc

I am calling it "LAN", that just represents your network's capacity to communicate within itself without going to the internet. More than likely it's a "WLAN" or something even more complicated than that ;-)

Hope that helps.
 
Old 10-09-2009, 11:16 AM   #3
scheidel21
Senior Member
 
Registered: Feb 2003
Location: CT
Distribution: Debian PPC/i386/AMD64 6/7, Vista, XP , WIN7, Server 03/08
Posts: 1,287

Original Poster
Rep: Reputation: 97
Thanks fr the information. I have all ready accoutned for local traffic in my internal numebrs game based on in/out traffic. There is some like multicast, broadcast, etc... I see what you are saying regarding apples to oranges comparison, however, the usage stats before and after monitoring were put in place are from ATT, The issue started before I implemented any monitoring, and was in response to a slow connection speed for everyone. We had not even looked at usage stats until this issue, I have since seen more than I care to recall, trending reports, daily, weekly, monthly hourly, god it sucked. I have also gone through logs, etc... since I started implementing monitoring etc.... My feeling personally is that this is legitamite traffic and there is nothing we can do besides get a bigger pipeline. But due to the wishes of my co-worker I am still beating this dead horse. Since all we have to go by is what has been collected since I started monitoring and usage stats from ATT that I can thankfully view. I don't think there is or ever will be a way to determine what changed if anything to cause this higher usage. If I can't see what was goign on before I can't find the difference. It's like trying o find the straw of hay that was added to the pile after the pile was initially collected. The only thing is that no one did an inventory of whatstraws of hay were there before the new one was added. So how do you tell which is new and which is old?
 
Old 10-09-2009, 06:35 PM   #4
in_texas_dallas
Member
 
Registered: Sep 2009
Location: DFW
Distribution: Debian Lenny
Posts: 38

Rep: Reputation: 17
Hrrm, hard to say. If you truly want to reduce bandwidth used, start selectively blocking parts of the internet... Start with video/picture hosting sites... external proxy sites... User web pages... facebook, myspace, twitter... Understandably people at your workplace probably have very legitimate reasons for accessing a good deal of the internet, but alot of frivolous surfing might be going on that can be eliminated.

Like, starting at this website: http://www.alexa.com/topsites

Go through and ban like the 20 most popular websites that are a) bandwidth intensive b) absolutely unncessary to the function of the job.

I know some companies use Facebook and twitter for marketing, but I doubt everybody has to have it enabled....

I can't say, it's just not adding up. If nothing changed quickly, it's either external or something built up... You could probably get a big chunk of bandwidth back if you lopped some of those worst offending sites...
 
  


Reply

Tags
att, bandwidth, bandwidthd, cacti, iftop, juniper, t1


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Two questions -- 1)ideas about bandwidth saturation 2)Network connection logger scheidel21 Linux - Networking 8 06-23-2009 02:37 PM
sSMTP / QMail Issues - Any ideas? jsurles Linux - General 1 09-24-2008 03:52 PM
Compiling issues Ive never seen before. Any ideas? libranikki Slackware 1 02-12-2005 08:48 AM
multiple hardware issues, need ideas! lukebeales Linux - Hardware 1 07-07-2004 06:14 AM
Bandwidth limitting Apache - ideas? Comrade Chez Linux - Networking 4 02-07-2004 05:47 AM


All times are GMT -5. The time now is 02:20 AM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration