Just upgraded my internet speed but getting nowhere near close to what it should be

[Supermercado]

Hi, I've had cable internet with the same company for about a year and a half. Until last night, I've had the standard package, 7Mbps down and I think it's 512Kbps up. I've been trying to do the new Netflix streaming to the Xbox 360 and been getting terrible results. I ran a few speed tests and lo and behold, the speed is only between 3 and 4Mbps. I suppose that should have been my first clue that something was wrong but I decided to go ahead and upgrade my cable connection last night, thinking that even if I wasn't getting the advertised 15Mbps down, I'd probably get 10 to 12 and be fine.

I've been trying all day to get it to actually test at 15 but I'm getting nothing close to it pretty much no matter what I do. I called the cable company first this morning and of course they had me plug my computer directly into the modem and try, so I did. I got the advertised 15Mbps down and 2Mbps up that way. Connected my router again (D-Link DGL-4300) and it's back to crap. It's been all over the map since I did that. It's peaked around 11 or 12 once or twice, stayed around 6 to 8 most of the time, and as of right now, I'm lucky to be getting 3.

I also talked to D-Link and they had me change all sorts of settings on the router and nothing was making any difference. It was fluctuating around a little bit as we tried stuff but my guess is that that's no big deal. A little fluctuation here and there is nothing, but I was still nowhere near 15. D-Link gave me a case number and said I could RMA the router but I'm not even convinced there's something wrong with it, honestly. I'm not a networking professional so I could be wrong.

Just now I tried connecting directly back to the modem to see what would happen and I couldn't even get connected at all. I tried restarting my laptop a couple times to no avail. It's back on the router now and it's back working but I just ran a speed test and it's just over 3. All this time, my upstream has been reasonably close to 2Mbps while the downstream is all over the place.

Does anyone have any idea what can be happening here? I'm all out of ideas on things to try, not convinced that the router is actually broken and in need of an RMA, and starting to get really frustrated.

 

[kevnich2]

Unplug power to cable modem. Hook your PC directly to the cable modem. Turn the cable modem power back on, restart your laptop. Then try speedtest again. From the looks of things, yes, it looks like your router may be causing the problem.

 

[Supermercado]

I'll try that and see what happens. I may also have an extra router that I can try to see if I can diagnose my router as being the source of the problem. Annoying, since this router isn't a cheap product and it shouldn't be doing this.

 

[spidey07]

My first guess would be a duplex mismatch from the modem to the router. Or a cable problem - don't use homemade cables.

Dumb question because I don't know your modem or your router...are the port on your modem and your router set to autonegotiate speed/duplex? They should be.

The throughput you are describing SCREAMS duplex mismatch.

 

[Crusty]

Originally posted by: Supermercado
I'll try that and see what happens. I may also have an extra router that I can try to see if I can diagnose my router as being the source of the problem. Annoying, since this router isn't a cheap product and it shouldn't be doing this.

It very well could be defective, and it looks D-Link seems to think that might be the case since the tech said you could RMA it if needed.

 

[spidey07]

Stick to network troubleshooting 101.

You cannot do it by process of elimination. You must start at layer1 - physical layer. Move on up the OSI model from there. Randomly swapping gear does not solve problems in this case.

This screams layer1 problem.

 

[Supermercado]

No homemade cables. These all came with one device or another at some point.

The only settings for speed or duplex that I can find anywhere is called "WAN Port Speed." The options there are "Auto 10/100Mbps," "10Mbps" and "100Mbps". I've tried all three of those and can't tell any difference.

I did try connecting directly to the modem again and got the full 15/2 so it's definitely router-related. I can't find much of anything searching for others that have had this same thing happen. I found one decent thread but the things that worked for the guy there made no difference for me.

I also tried two more routers just to see and I couldn't get online with either of those at all. Tried restarting my laptop a few times, resetting the routers to factory settings, power cycling the modem, nothing. Last I knew, both those routers worked.

I don't really want to pay to ship this thing back to D-Link. I'm tempted to just buy another WRT54GL and put DD-WRT on it. I've already got one that I use as a bridge to my living room and it works flawlessly.

 

[VirtualLarry]

Optimized your LAN TCP/IP stack? Then again, if you are getting full BW from directly hooking up to the cablemodem, then that's probably not the problem.

 

[Supermercado]

I'm not even sure how to do that. I've never seen an option like that in my router setup.

 

[Madwand1]

Did you try (recording the settings and then) resetting the DGL-4300 to factory defaults?

You could also try different MTU settings on the router (in Basic, Internet, Manual, DNS and Advanced, Advanced, MTU), and then try disabling SPI and Game Fuel, etc., (in Advanced/Firewall and Advanced/GameFuel).

 

[kevnich2]

To try a different router, unplug the power to your cable modem, hook the new router up to the cable modem (without power). Then plug power back to your cable modem, wait 1-2 minutes, then plug power into your new router, wait another minute and then try your computer out.

 

[Supermercado]

Update on this...

I tried resetting the D-Link to factory defaults and without changing any settings at all, ran the speedtest again. Got more or less the exact same results (<1000Kbps difference) as I've been getting the last few days. I reloaded my saved configuration file and ran the test again: also got the same results I've been getting.

I also tried changing all sorts of settings before I went back to the factory defaults and none of those made any difference, either. Those were the same things I tried while on the phone with the D-Link tech. He didn't have me change the MTU settings at all but I did try changing those on my own.

I also tried a different router, an old 802.11b Netgear with factory defaults. I was getting the advertised speeds, both up and down (I still don't understand how the D-Link can give me adequate upstream but horrible downstream; anyone have any thoughts on that?). So it's definitely the D-Link and since I went to factory defaults, it would seem to be a hardware issue with the router.

I guess it's time to have them send me a new one (I'm sure it will be a refurb, however) and try that. I suppose that if I have problems at that point, the problem will be isolated to the router and it'll be on them to resolve it. A few bucks shipping to ship mine back to them - assuming the replacement works - is definitely better than another $60 on another Linksys to put DD-WRT on.

 

[Slowlearner]

I have had good results from following these steps:

1. Run a speed test at any of the NDT servers - http://nitro.ucsc.edu/ - has given me the most consistent results.

2. Once the test finishes click on the Statistics tab << This will tell you if the NIC is problem or there is bad cable.

3. Next click on the More Details tab - scroll down to the bottom to see if the receive buffer size is a problem.

4. If that is indeed the problem, go to http://www.dslreports.com/tweaks, and run a Tweak test. If the Results tab suggests making changes - download a tool called Dr TCP<< http://www.dslreports.com/drtcp- that helps you make registry changes to improve your download speeds.

5. Reboot and you may see an improvement. Dont, however, bet on it.

 

[Supermercado]

"Your PC/workstation has a 62.0 KByte buffer which limits the throughput to 3.93 Mbps"

Is that the receiver buffer you're talking about?

I can modify my computers to my heart's content but the real thing I'm worried about is my Xbox 360. I know the options for configuring the network-related things on the 360 will be nowhere near as comprehensive as on a computer. Even if I got the computers working, I still think I'd be out of luck on the 360.