Internet speeds keep dripping, however crossover test shows full speed

[jhammond]

Hi,

 

I have been having this really annoying issue where the internet seems to drop to an unusable speed say 0.4Mbps. When I do ping tests these either drop out or take an unusually long time. I can still ping the router no problem.

 

Each time this happens i have been going to the router and performing a Cross over test and the speeds are coming back just as they should with no drop in speed and all ping tests are coming back. the router has been replaced two times and upgraded to a Cisco 2800 series; however this issue keeps occurring.

 

I have been onto the main switch and even reset this to its default settings.

 

I also reset the router and this does not improve the speed.

 

any help will be much appreciated as the slow internet is driving me mad! Not to mention all the teachers!

 

Thanks

James

[bodminman]

We had something similar the other week and it was down to an issue to the ntp server setup on our filtering box. Lightspeed fixed it in a jiffy!

 

Prior to figuring this out and whilst pinging various things at the same time, I disconnected various segments of the network from the central comms cab to eliminate something dodgy from elsewhere on the network like a loop etc.

 

However, my process of elimination guided me to the Lightspeed box in the end.

Edited February 26, 2014 by bodminman

[jhammond]

I would, disconnect just like you, however this keeps happening in the middle of the day; normally by the afternoon when i can unplug bits the speed is back up. It is so frustrating.

 

for example today the speed dropped at 12, and has just come back up now before School has ended and before i can do the testing.

[jhammond]

I have done some testing and it seems that it is the exchange server that is causing these issue.

 

It may be when mail merges are being sent out.

 

Do you have any ideas on how to stop this from grinding the internet to a halt?

[Michael]

You say bandwidth drops to 0.4Mbps, but what should the actual speed be?

 

Of course when you're sending mail merges, this uses your upload (if sending to parents for example), so yes, it's no wonder it can stress the connection out.

 

It may be better to schedule these sort of things either first thing of the day or last thing at night. Alternatively look at broadband upgrades if available to your area.

[jhammond]

i am looking to upgrade the line as soon as possible. Have also done much research into this. It is just annoying that this is causing such a strain on the internet.

[jhammond]

the actual speed is 20Mbps

 

I have just done some more tests and it seems that any external mail is causing the internet speed to drop significantly, even when only 2 or 3 messages are being sent.

 

Any suggestions?

[Michael]

Seems a bit of a weird one. So you're on ADSL, such as 20Mbps down, 10Mbps up, or on a lease line operating at 20Mbps each way?

[jhammond]

we have an adsl2 line with 20Mpbs down and 0.4Mpbs up

[Michael]

we have an adsl2 line with 20Mpbs down and 0.4Mpbs up

 

Well there's your problem. The upload rate is poor, so it's no wonder even the smallest amount of traffic slows everything up.

 

I'm not entirely sure how the ratios work for ADSL, but for a 20Mbps download you'd expect at least 5Mbps+ as the upload.

[DMcCoy]

we have an adsl2 line with 20Mpbs down and 0.4Mpbs up

 

Then the upload speed is the problem, you should be able to get that increased to around 1Mb with adsl2. Your acks for the download side are being delayed due to the uploads.

[cpjitservices]

Are you using any sort of firewalling / UTM device ?

[jhammond]

hi we just have a rm smartcache and on the exchange server we have Symantec antivirus and Symantec Mail security

[jhammond]

Hi DMcCoy,

 

so are you saying that as my upload speeds are so slow this is halting the download speeds?

[Michael]

Hi DMcCoy,

 

so are you saying that as my upload speeds are so slow this is halting the download speeds?

 

That's correct yes

[jhammond]

Do you think there is any way around this for the moment, until i get the internet line upgraded.

[Michael]

I'd contact your ISP as it should be considerably higher for a 20Mbps connection.