Wireless access point + U-verse = very inconsistent speeds

SamS_1 · ‎09-02-2010

Hi all,

I've had U-verse for over a year, and consider myself fairly adept at trouble-shooting network/WiFi problems. However, I'm about to throw in the towel on this, so I figured I'd check in here first.

My set-up: RG to a 24-port D-Link DGS-1024 Gigabit switch then to Netgear GS-108 Gigabit switches in each room. Everything is run with Cat-5e in the house. My wireless access point is the Cisco WAP4100N, which is a decent B/G/N small biz access point. I've tried several Linksys APs before with the same 'problem'. The WAP hangs off of a GS-108 switch.

My problem is that my internet over WiFi is very inconsistent in speeds, and often time just drags to a halt. Much of the time, it is blazing fast, well over 5Mbps down. However, sometimes, it slows to a crawl, not even reaching 50kbps up/down with pings in the 13000ms range :-( I realize the obvious culprit would be overlapping WiFi channels with a neighbor, but I don't think this is a problem. I've ran inSSIDer dozens of times and found channel 11 to be pretty clear and I have good signal strength. My firmware on the WAP is up to date, and I went through two other WAPs thinking they were the problem, only to realize the same inconsistency on each.

What else could I try? Could it be the cascading switches conflicting with the Access Point? RG WiFi is turned off. Even when the up/down speed is literally 10kpbs via SpeedTest, I can use my iPhone4 to control other devices via WiFi on the LAN and there doesn't seem to be a delay. So, I guess I'm bouncing around the LAN pretty fast, which rules out WiFi interference.

spd2demun · ‎07-28-2007

Might try SomeJoe's excellent post on on Wireless Interference for more ideas?

SamS_1 · ‎09-02-2010

Thanks. I did see that (great!) post via a seach when I first got here. I knew/understood much of that info,

mibrnsurg · ‎07-15-2008

Looks like you've set up ethernet points all around the house, use em and get full speed and drop using wireless.

Chris

______________________________________________________________________________

Please NO SD stretch-o-vision or 480 SD HD Channels
1-866-465-1496 for direct TS to avoid Mr. Voice recognition
Your Results May Vary, In My Humble Opinion
I Call It Like I See It, Simply a U-verse user, nothing more

SamS_1 · ‎09-02-2010

Trust me, I use hard wire ports whenever possible

It's when my wife and I are on our laptops that we really feel the pain.

mibrnsurg · ‎07-15-2008

Good cheap ethernet cables for great speed on laptops:

http://www.monoprice.com/products/subdepartment.asp?c_id=105&cp_id=10208

Just because it's a laptop, can still be plugged in for full speed, no drop outs.

Wireless is just not the panacea many tout it to be in many situations filled w/interference.

Chris

___________________________________________________________________________

Please NO SD stretch-o-vision or 480 SD HD Channels
1-866-465-1496 for direct TS to avoid Mr. Voice recognition
Your Results May Vary, In My Humble Opinion
I Call It Like I See It, Simply a U-verse user, nothing more

SamS_1 · ‎09-02-2010

I do appreciate the suggestion, but wiring up the laptop is not really an option for when my wife is sitting on the couch, bed, outside on the patio, etc. Trust me, this frustration has already caused me to wire up every bedroom in the house with Cat5e and the kitchen(!) as well.

Sometimes you just need WiFi. And when the speed varies from 6Mbps download, to literally 15kbps download, it is maddening.

mibrnsurg wrote:
Good cheap ethernet cables for great speed on laptops:

http://www.monoprice.com/products/subdepartment.asp?c_id=105&cp_id=10208

Just because it's a laptop, can still be plugged in for full speed, no drop outs.

Wireless is just not the panacea many tout it to be in many situations filled w/interference.

Chris
___________________________________________________________________________
Please NO SD stretch-o-vision or 480 SD HD Channels
1-866-465-1496 for direct TS to avoid Mr. Voice recognition
Your Results May Vary, In My Humble Opinion
I Call It Like I See It, Simply a U-verse user, nothing more

SamS_1 · ‎09-02-2010

OK, problem solved!

I moved the WAP from behind the two Gigabit switches, and hung it directly off the RG. That doesn't put it in the best spot in the house, but coverage is still decent. Speeds are faster than they've ever been, and 100% consistent.

Now, if someone could only fix all the pixelization I see on my bigger HDTVs with U-verse

spd2demun · ‎07-28-2007

Good deal, and one thing at a time, LOL!

SomeJoe7777 · ‎01-30-2008

My hunch is that your WAP was getting so much broadcast traffic (from the U-Verse video streams) that it was overwhelmed. Your switches aren't separating computer traffic and IPTV traffic, and since IPTV is multicast, it goes to every port.

When the WAP is on the RG, the RG's IGMP snooping prevents the IPTV traffic from reaching the WAP.

SamS_1 · ‎09-02-2010

SomeJoe7777 wrote:
My hunch is that your WAP was getting so much broadcast traffic (from the U-Verse video streams) that it was overwhelmed. Your switches aren't separating computer traffic and IPTV traffic, and since IPTV is multicast, it goes to every port.

When the WAP is on the RG, the RG's IGMP snooping prevents the IPTV traffic from reaching the WAP.

VERY interesting, and makes total sense. All my U-verse boxes are hard wired behind GS108 switches (including where the WAP was), does this still make you theory work?

And if this indeed the case, with IPTV being multi-cast and overloading the WAP, why is are other network devices behind the switches not affected as well?

SomeJoe7777 · ‎01-30-2008

SamS wrote:

VERY interesting, and makes total sense. All my U-verse boxes are hard wired behind GS108 switches (including where the WAP was), does this still make you theory work?

And if this indeed the case, with IPTV being multi-cast and overloading the WAP, why is are other network devices behind the switches not affected as well?

Yes, both your D-Link switch and the GS108 switches do not do IGMP. Thus, any multicast packet entering them is treated as broadcast traffic and is forwarded to every port. This doesn't bother the switches too much because they're gigabit.

Any device on the network has an Ethernet card (or link chip) that examines all frames on the network. The card rejects frames that aren't destined for it's MAC address in hardware. But broadcast and multicast packets can't be examined and accepted/rejected at the hardware level, they have to be passed up the network stack and let the software determine whether the packet is something they need to process or not.

For computers and other larger devices with beefy processors, it's not too bad to have to examine every multicast or broadcast packet. But for the WAP, the CPU is a lightweight processor and examining all the multicast packets in software is too much for it.

The solution to this is IGMP snooping, which the RG implements. IGMP snooping is available in some enterprise-level network switches, but the flavor of IGMP used by U-Verse is IGMP v3, and many enterprise switches with IGMP snooping capability will not isolate multicast traffic using IGMP v3, but instead operate only with IGMP v2.

A less expensive method that leverages the RG's ability to do IGMP v3 snooping is to separate the network traffic using VLANs. Click the "Posts" tab in my signature below, and click on the link that says "Measure Internet Usage" for an example of how to segment the network and separate IPTV and computer traffic using VLANs and SOHO switches.

SamS_1 · ‎09-02-2010

Great explaination, and makes total sense. I was actually typing a new thread on this sub-topic of IGMP snooping when I saw your reply come in. Maybe we can continue here if you don't mind.

My "in room" switches are all GS108v3, not GS108T. Is that going to make it impossible to set up a VLAN? I understand the concept of a VLAN, I've just never done it before.

My main switch, a DLink DGS-1024D is unmanaged as well. Can I even set up a VLAN with the gear I have? Should I even worry about it? My other networked devices include PCs, laptops, NAS, and Logitech streaming Squeezebox products, and a few other AV devices like receivers and Blu-ray players. I haven't run into a real problem with anything other than the WAP so far. But, if you think I can set up a VLAN for just my U-verse boxes, I'm willing to give it a shot.

SomeJoe7777 · ‎01-30-2008

Neither the GS108 switches nor the DLink switch have VLAN capability. To set up VLANs you would need to get GS108T switches.

If the WAP was the only device that was having problems, then perhaps VLANs aren't necessary in your case.

SamS_1 · ‎09-02-2010

OK good to know.

I guess if I get a wild hair in the future, I can just look to replace my existing switches with ones that support IGMPv3? Then, the multicast flooding will be automatically mitigated by the switches, and I won't even have to bother with VLAN. Correct?

SomeJoe7777 · ‎01-30-2008

SamS wrote:

OK good to know.

I guess if I get a wild hair in the future, I can just look to replace my existing switches with ones that support IGMPv3? Then, the multicast flooding will be automatically mitigated by the switches, and I won't even have to bother with VLAN. Correct?

Yes, but switches that support VLANs are fairly cheap (GS-108T is about $90), switches that support IGMP v3 are rare and expensive.

SamS_1 · ‎09-02-2010

Hi again,

Bumping up my old topic, as I'm considering moving to a VLAN.

Is there any way to measure just how much the U-verse multi-cast flooding is impeding my LAN performance? Obviously I got the WiFi to work with no problem, I just wonder if my other network traffic is suffering.

Have IGMPv3 switches come down in price at all?

Just how hard would it be to set up a VLAN with one main 24 port switch + three 8-port switches, considering I've never set up a VLAN before?

SomeJoe7777 · ‎01-30-2008

I would say that with Gigabit switches like you have, the multicast traffic isn't hurting anything. The switches can carry a minimum of 1 Gbps of traffic on their backplanes, while even with all streams going on U-Verse, it doesn't amount to more than about 35 Mbps of aggregate traffic.

Unless you're really having a noticeable issue, I wouldn't worry about it. VLANs aren't particularly easy to set up, plus you would need 4 new switches including a central one that's more than 8 ports. That puts you in need of something like 3x Netgear GS-108T switches (about $300) and something like a Dell PowerConnect 2816 or 2824 for the central switch ($225 - $275). At a total of nearly $600, that's a lot to spend if nothing's really causing a problem.

SamS_1 · ‎09-02-2010

Thanks SomeJoe.

I went reading through some of your posts, including the one from earlier this month where you gave someone more specific tips on setting up a VLAN. I even found that diagram you made. The configuration all makes sense in my head. Of course implementing it is typically much trickier

Yes, I would definitely need all new switches, and I'm not really in the mood to spend the $600 like you're describing. I just got done setting up a dedicated 15U Sanus rack for all my networking gear: http://i193.photobucket.com/albums/z36/BeatCrazy/Rack.jpg

Obviously all that was not cheap! You can see the HGV3801 at the top right, on a rear-mounted 1U shelf.

I also replaced all of my Cat5e runs in the house with Cat6 cable that was more length-appropriate to each room. Either the shorter length (i.e. 120ft down to 60ft runs), or the Cat6 made an improvement with my overall U-verse STBs. I realize we're only talking about 100Mbps ports on the AT&T devices, but I swear STB interaction with the DVR is much faster.

The Cat5e was originally put in via my original U-verse installation, so there wasn't much regard to routing in the attic, avoiding kinks, etc.

SamS_1 · ‎09-02-2010

I actually figured out a way to separate out the multi-cast traffic without VLANs or IGMPv3 Snooping switches.

With a bit of work (but it's a free solution), I can get dedicated drops to each STB and the DVR. I'll run those to an 8-port switch which I can connect directly to the RG. The RG will still connect to my main switch, and supply internet to all the other devices. Should work, right? Or am I just wasting time?

SomeJoe7777 · ‎01-30-2008

Yes, that will work. What you're essentially doing is creating two physical networks within your home, and each is plugged into 1 Ethernet port on the RG. That way, the RG will separate the traffic using it's built-in IGMP snooping.

This is essentially the same thing that a VLAN setup does, but the VLAN reduces the amount of cabling required since each LAN is separated logically (but on the same Ethernet cable) instead of being separated physically on 2 Ethernet cables.

SamS_1 · ‎09-02-2010

OK cool. I'm going to give it a shot next weekend. I need to run an extra drop to the master bedroom. Last weekend I pulled dual drops to my other rooms with TVs.