You mean I can just BUY a bigger pipe?

November 23, 2010 4:52 PM

Is my wireless router's tube clogged?

The basic question is whether buying a new router will allow me to use all of the internet bandwidth available to me, or if I need another solution. Details:

I just got Comcast 10 Mbps service installed. To test things out, I connected my desktop computer directly to the cable modem and hit up speedtest.net. The results surprised me - a consistent 20 Mbps download (and 3 Mbps up, but upload speed isn’t a big deal to me). Then I broke out the little D-Link DI-524 that has been a trustworthy pal for years. Once I connected the desktop to the router, I ran speedtest.net from the desktop again, and my results were consistently 15 Mbps. I turned off the router's wireless signal so the desktop was the only computer connected to the router (and therefore the only computer connected to the modem) and consistantly got the same results - 15 Mbps when I go through the router vs. 20 when connected straight to the modem.

It doesn't look like a problem with ethernet cables - I'm using the same cable to connect the router's WAN port to the modem and the computer directly to the modem, and I've tried using several cables to connect my PC to a variety of ports on the router, all with the same result. As far as I can tell, going through my little router is limiting my download bandwidth to about 15 Mbps, even though Googling indicates that the WAN ethernet port on my router is 100 Mbps ethernet.

Even though I was plodding along with a 4 Mbps connection last week and am only paying for 10 Mbps service, I want that extra 5 Mbps! Nay, I am ENTITLED to that additional 5 Mbps!

So here are my questions in detail:
1. Is it true that the DI-524 is slowing me down? Or am I overlooking other, more likely explanations?
2. Is there anything I can do to my DI-524 router to speed it up, or is it forever limited to 15 Mbps downloads?
3. If I can’t speed up my router, my plan is to just buy a cheap router that supports a 100 Mbps WAN connection, disable DHCP on my DI-524 to use it as a switch/hub, and hope that the cheap new router can actually handle the advertised 100 Mbps WAN connection. That should work, right?
(I’m eyeing an upgrade to a 802.11n wireless router with gigabit ethernet so I can do fun things with my home network, but I’d like to know whether the cheap wired router option would work for now).

posted by Tehhund to Computers & Internet (19 answers total)

Do you have the firewall or QOS enabled in the router?
posted by bizwank at 4:59 PM on November 23, 2010 [1 favorite]

Response by poster: The firewall is enabled. I'm not sure what you're referring to with QOS - can you clarify so I can check?
posted by Tehhund at 5:01 PM on November 23, 2010

even though Googling indicates that the WAN ethernet port on my router is 100 Mbps ethernet.

I don't know what the problem is, but your wireless should be capable of 54 Mbps. That said, you may have a noisy radio environment getting in the way. I can't imagine that 802.11n would fix this issue.
posted by pompomtom at 5:01 PM on November 23, 2010

Response by poster: The 802.11n isn't related to this issue - I'm doing all of these tests over CAT5 cable. So just ignore that part of the question, I realized it's not relevant.
posted by Tehhund at 5:03 PM on November 23, 2010

QoS refers to Quality of Service. If enabled, it will limit bandwidth of some applications to ensure that other services will have remaining bandwidth. For instance, you may limit typical torrent ports to, say, 5Mbps so that other computers or programs still have bandwidth available to operate..

If you have a second computer and command line skills, check the bandwidth through the router with Iperf. Iperf does a test from one pc to another where it tries to send as much data as possible. When using it for work, my ethernet connections through a switch were running at 92-95Mbps, which this router should do as well.
posted by Mister Fabulous at 5:07 PM on November 23, 2010

Those routers are little computers; it's not at all surprising that the throughput of it isn't up to the task, since it was built at a time when 20mbps likely wasn't available or at least not common.

In recent years, sites like Tom's Hardware have taken to measuring the WAN throughput of routers, to help consumers like you avoid routers that slow things down. You'll do well to retire that trusty little fellah and replace it with something capable of passing through your full bandwidth, since you're lucky enough to have it.
posted by davejay at 5:08 PM on November 23, 2010 [1 favorite]

Best answer: The DI-524 probably is slowing you down. Older home routers just don't have the CPU speed to push packets at those speeds. When they were designed, 6Mbps was probably the fastest home internet possible, so they didn't bother getting faster CPUs. Getting a cheap wired router may not help you, either, if it's an old design. Just get a new wireless router.

Datapoint: at work we get 12Mbps AT&T Uverse service, and our oooold Netgear wired router couldn't move the bits any faster than about 5Mbps. Getting a newer router fixed the problem.
posted by zsazsa at 5:10 PM on November 23, 2010

Try disabling the firewall and anything else in the router that may be inspecting the packets before it passes them on, and run the test again. Doesn't look like it has QOS so you can ignore that. Does it have the most recent firmware installed?
posted by bizwank at 5:11 PM on November 23, 2010

Response by poster: I connected another computer to the router via ethernet cable and used netspeed to do what Mister Fabulous suggested. The two computers can communicate with each other at just over 85 Mbps in both directions. So there's no throttling happening on the LAN - of course, there could be some WAN-to-LAN throttling.

Thanks for the ideas, keep them coming.
posted by Tehhund at 5:17 PM on November 23, 2010

Response by poster: There's no on/off switch for the firewall that I can find, so I disabled every rule that I could. No change.
posted by Tehhund at 5:19 PM on November 23, 2010

A 2005 review of the WRT54G, which seems to be of a similar vintage to your router, has test results showing throughput of ~20Mbps LAN->WAN and vice versa. It sounds like that speed is near the upper end of what was available at the time. Also, it was under ideal conditions, with the WAN-side test machine connected via 100Mbps ethernet, though it may be that the test software simulated Internet like latency.

In any case, it sounds completely plausible that your router just can't do better than 15Mbps. Your time is probably better spent researching what router to upgrade to.
posted by Good Brain at 6:00 PM on November 23, 2010 [1 favorite]

davejay, zsazsa, and Good Brain have it; those little DLink's just don't have the grunt to do everything they're asked to do at those sorts of speeds (specifically, NAT tracking & routing). Personally, I'm surprised you're getting 15Mbps out of it - maxing out at 10~12 would be more in line with my experience, and I've seen them drop well below that when heavily loaded with lots of client connections e.g. multiple PCs or bittorrent.

In answer to part 3, I'd expect that it can handle it when running purely as a switch - IIRC, they had a separate switch chip & didn't rely on the processor to do everything - but, honestly, you may as well ditch it and get a decent router with a 4 port switch built in.

(And from what I remember, the Linksys WRT310 you link isn't that good a performer either - but don't quote me on that…)
posted by Pinback at 6:30 PM on November 23, 2010 [1 favorite]

The other callers have it, the thing just doesn't have enough firepower. The switch part of it is just fine. But the NAT part needs processing power, and you can't get that cheaply. And the software engineering seems to be geared toward "good enough, now what color do you want the GUI to be?"

I replaced a WRT54G with a PentiumIII 866 and the cheapest network cards I had, configured it myself (not an expert), and its speed blows the WRT54G away. I suspect that review wasn't testing it with NAT turned on.

There is a reason proper routers cost thousands of dollars- better hardware.
posted by gjc at 7:27 PM on November 23, 2010 [1 favorite]

I'm sure the router is running some form of linux, which uses the same program to do NAT and firewalling. Without turning off both, you probably won't get any speed difference. You might not at all, potentially, because of the possibility that the WAN port and the LAN port/switch are connected via a crappy PCI-type bus, and not the switch backplane bus.
posted by gjc at 7:30 PM on November 23, 2010

You are probably seeing a feature of cable internet service called speedboost. It gives you greater than subscribed speed for a very brief period of time. Here is a discussion of it for customers on Teksavvy's cable service here in Toronto. I googled around for other references, but nothing stood out..

As for the issue with the Dlink.. The others are probably right, the CPU in the router is probably choking. However, the router might be set up in some way that doesn't allow the speedboost feature to work quite as well as it might. Or you might be testing at different times of day. Your actual speed is going to depend on the congestion level of the providers network. Finally, always pay attention to MTU settings. I think yours should be 1500, but experimenting is good.

To find out if this is speedboost, download something big and calculate manually. If it is speedboost, you probably won't gain anything substantial from changing the router. If you really do have a full on 20mbps connection, a router upgrade might be in order.
posted by Chuckles at 12:01 AM on November 24, 2010

Are you sure you actually need a separate router? Lots of "modems" actually have routing inbuilt. If your computer gets an IP address in the 192.168.x.x or 10.x.x.x range when you hook it straight to the modem, there's a good chance that your modem is actually a NAT router and all you need to use to hook multiple computers to it is an Ethernet switch - which you already have: it's the LAN side of your little D-Link router, which you've already shown is capable of high throughput. All you should need to do to make it all work is turn off the DHCP server in the D-Link box, and hook it to the modem via one of the LAN ports instead of the WAN port.
posted by flabdablet at 2:56 AM on November 24, 2010

Response by poster: Chuckles, I had not thought of speedboost (Comcast calls it "powerboost") - I'll see if I can test around it in the future to see whether I'm really getting 20 Mbps. At the moment I'm not sure where can I find a few giant downloads whose hosts will give me enough bandwidth to hit a consistent 20 Mbps. And even if it is powerboost, if I can get 20 Mbps temporarily, I want it - and the router is still holding me back.

flabdablet, plugging the modem into the LAN side would be a good solution, but when I connect the computer directly to the modem I get what looks like a public IP (i.e., not in the 10.xxx.xxx.xxx, 172.xxx.xxx.xxx, or 192.xxx.xxx.xxx range). So I guess that's out.

Thanks all, I'm going to keep fiddling with it, but it sounds like consensus is that the old router's CPU just can't the speed. I had a suspicion that this was the issue, but I thought I'd check my wild guess.
posted by Tehhund at 6:05 AM on November 24, 2010

If the modem has a web server inside it, and especially if your ISP credentials are stored inside the modem rather than whatever you hook in downstream of it, I'd try poking around in its configuration pages and seeing if NAT can be turned on inside it.

If you do manage to do that, you might then find that the modem chokes on the job as badly as your little router did before it. Still worth playing with.

If not, TP-Link gear is really cheap and usually works well. Combining this 802.11n router with a separate gigabit switch should make for a very fun home network.
posted by flabdablet at 7:28 AM on November 24, 2010

And even if it is powerboost, if I can get 20 Mbps temporarily, I want it - and the router is still holding me back.

Maybe not.. If you are dealing with powerboost, it might just be an artifact of the measurement technique.
posted by Chuckles at 10:25 AM on November 24, 2010