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Re: [Speed] PSA: Slow WiFi on Comcast? May be Comcasts Fault

WMM specification

It's not, I just think that post was from someone who just doesn't really know.

Edit : I did find an article about APPLE products not connecting to N if it's disabled

»support.apple.com/kb/TS3727

Before I posted, I disabled it & the re-enabled just for the fun of it with no negative issues.

Found this is an article :

"Since WMM support is required for products to be certified for 802.11n, WMM comes enabled by default in all Wi-Fi Certified n APs and wireless routers. So even if you don't have any WMM-aware devices on your network, leave WMM enabled or you may find your clients connecting only at 54 Mbps rates."

But this is not true in my case, I am connected at 130mbps at the moment. So either these people don' know what they are talking about, or this might be with certain chipsets.

I just got done trying a few things out by disabling WMM & here is the rub. In a mixed network on my 2.4GHz, I had no issues connecting with "N" devices, but indeed they were bumped down to "G" speeds. My 5GHz network was unobtainable. So, I would say with my router I can not disable WMM and use "N" only.

Here's an interesting post about someone who is having a WMM issue.
One machine seems to get affected by it being off, another works fine.
»communities.intel.com/thread/30932
As per intel's response, WMM is needed for some IEEE spec adherence in wifi n.

Even though this is a different issue than what started the thread it illustrates how complicated this issue is as a whole, Wireless N (speeds over 54), QOS field, WMM conformance.
Some routers don't care what the incomming QOS in the packet is, some do.
Some wifi adapters don't care if WMM is on, some do.
All of this is creating compensatory arguments for who is correct or not.

Well, that's the only setting for WMM I have.

You don't have that option in your router?

That's the only WMM option for my adapter.

I definitely think its their fault too. If you look at the issue as a whole, fixing the downstream packets on their end would yield the best bang for buck ratio, and fix most of the situations.
I think they're doing it cause of special service prioritization. I read awhile back that there are some "special services" which were cap exempt, like their skype thing. At least when they still had the cap.
Maybe they kept it around for congestion priority though. Are there some online, direct from comcast, streaming services? I bet they'd have a different priority number in that field.

Anyway, its just bad management on their part. I'm a programmer, when I use something that could potentially be shared, i need to clean up after myself, lest I incur unwanted side-effects. The same should be applied here.

Thanks for your time in figuring this out.

Wow, can verify that this made a huge difference in d/l speeds on a Netgear WNR3500L running Toastman's K26 Tomato 1.28. Before the DSCP change could only get 16-20mbps WAN-to-LAN max on wireless, after now get around 45mbps. LAN-to-LAN was always around 60-64 so I knew something was screwy going out the WAN. This is on Comcast Blast tier btw, I get 50-55 d/l on wired Ethernet.

Thanks OP, one thing though - when I copy/pasted the iptables command the double dashes before set-dscp didn't go over correctly in Chrome, ended up as a nonprintable char. Had to correct that manually, hopefully this one is right:

iptables -t mangle -A PREROUTING -i vlan2 -j DSCP --set-dscp 0

That's interesting. I'm using a WNDR3700 v2 with DD-WRT build 21676, and there doesn't seem to be an option for WMM anywhere. I found one person mention that it's permanently enabled for Atheros-based firmware, which is the SoC my router uses.

I just checked on my laptop and it gets the same speeds as my wired PCs (83/16 on 75/15). Wireless to LAN was 105-130 Mbps. It did 193 a few days ago, in the exact same spot. Yay wireless .

One thing that I'm curious about is how long this has been happening.
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KI6RIT

I would guess its a much more noticeable issue on certain broadcom based routers.

Thanks for the fix. I am using e3000 with shibby 112. Wan->Lan via wifi speed increases from 20mpbs to 57mbps.

Just to give everyone a heads up we are looking at this right now trying to recreate it..
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Comcaster.. Network Engineer with NETO

The tests I see so far don't have the DSCP values set on the WAN interface of the modem..
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Comcaster.. Network Engineer with NETO

alix 6d2 running pfsense 2.1 directly connected to the modem capturing packets on the WAN

I have a packet capture from my router's WAN interface showing DSCP = 0x08 on inbound packets, both IPv4 and IPv6. NetDog, I can PM you a link if you're interested.