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summitMISFlag for United States of America

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Internet upload speeds

We currently have a CDIR block of IPs from our cable provider.
We are having some issues with the upload speeds.
We are supposed to be getting 75/18, but currently only getting roughly 75/5.
We have worked with our ISP and had their techs come out and check the speeds, but when they connect their service laptops to the modem, they get the full 75/18 using the same speed tests as we tried.
Because of this, they will no longer assist as they claim we are getting the stated speeds.
We have tried several different computers, running Win 7 and Win SVR 2008.
All the computers we try gave the same results, 75/5 or worse.
The computers where also connected directly to the modem, no switches, routers, etc.
Is there something in our network settings that could be restricting our upload speeds?
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Esteban Blanco
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Firewall?  Anti-virus?  Go to SafeMode with Networking and see what the speeds are.  What about your switch or router?
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No firewall, no anti-virus.
As stated in the original post, no router or switch, directly connected from the computers network cards to the cable modem.
Try going on SafeMode with Networking and run the speed test.  See what you get.
The speeds tests will not run under safemode. The techs also did not use safe mode on their laptops that where getting full speeds.
That's odd.  I was able to test it here on safe mode with networking.  That will take out the possibility of being something but the OS (software that may be always downloading, software at startup, plug-ins, etc.)

So this is only happening on certain laptops (ISP tech laptop ran without an issue connected directly to the modem on regular Windows).

Let me think a little more.  I was able to hit F8 on my laptop and test Internet speeds on safe mode with networking.

Since you are not running anti-virus or firewalls in Windows and also you do not have anything but connection to the modem (no switches or routers)...golly.  

Let me think more here.  I know sometimes Firefox can add a Java plugin that can slow your Internet speeds down but I assume your server doesn't have that (or Java) for that matter.  When you look at the Task Manager under networking, what is the network utilization?
If I am reading correctly, the service tech came and plugged in their laptop with the modem directly and got the desired speed.

You, on the other hand plugging own laptop directly with the modem not getting the same result???
Assuming that ISP technician run his test correctly, then there is no other way, but issue with yours PC's.
You can have virus running on one of the PC, affecting your upload.
One of other easiest way, is to insist to replace your ISP router, it cost them nothing, but will take this part out of equation.
We used a laptop, server and a brand new workstation freshly built.  I doubt it's a virus unless it has infected each of these computers, including the one never connected to the net before.
The modem has already been replaced with a brand new one, that was one of the first steps the ISP did.
ic.
One of the other major factor, could affect you speed is MTU, you can manually set it up, or adjust MTU's (LAN +WAN interface+ PC's), while monitoring speed, across LAN or across WAN, using jperf for example
http://openmaniak.com/iperf.php

"engineering toolset" from www.solarwinds.com can be helpful to.

Some more detail how determine MTU and so on
http://www.dslreports.com/faq/5793

with those test, you dont find neccesarily the best MTU size, only the max MTU prior fragmentation.


For example, 1492 its the maximum MTU for pppoe, but its not optimal:

ATM cell have a fix lenght of 53 bytes, 5 for headers plus 48 for data. Any dont full cell will be padded to 48 bytes.

1492 + PPPoe Protocol header = 1500 Bytes + Ethernet Headder = 1518 Bytes

1518 on 48 bytes per cell -> 1518 / 48 = 31 cells, 30 Bytes remain, so you need 32 cells, the last cell with 10 bytes of padding (48 - 32 - 8 ). Last 8 bytes are neccesary for SAR (Segmentation and Reassembly flags)

In this example, for PPPoE, optimal MTU should be 1454:

1480 bytes per ethernet frame. 1480 / 48 = 30 cells, 40 bytes remains. So you need a maximun of 31 cells. The last cell dont need any padding, 40 ramains byte plus 8 SAR bytes = 48 Bytes.


So in really, in this example, a MTU of 1454 its more efficient that a MTU of 1492.
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summitMIS
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Problem went away by itself, unknown what the actual solution was as none of them had been tried.