WAP121 extremely slow

[zacmutrux]

A client contacted me for assistance with their wireless network. They had just purchased three WAP121 wireless access points and upon setting them up discovered the devices provided extremely slow access to the Internet. They have cable Internet service from Comcast and when attached to Ethernet or an older wireless router, speedtest.net shows download speed of 30Mbps. But when connected to any one of the three WAP121 devices they get less than 1 Mbps down.

Upon reviewing the settings with Cisco tier 1 support nothing seems amiss. The issue persists even when the AP is transported to another site. I am awaiting contact from tier 2.

Anyone else seeing this kind of behavior?

[wshservices]

HI Rick,

Thnaks for the welcome, I know - I have been following the various comments just through Google web search, I decided to join the forum as my customer is getting more and more annoyed. Are cisco offering any kind of return and upgrade policy on the 121's? I maybe wrong but people seem (to my knowledge) not be having as many issues with the 321's.. I only ask as surely a product must be fit for purpose, there are so many comments over various forums I would regard the 121's unfit for sale.

Regards John

[sysadminlca]

I know this is probably a long dead post... but I ended up here using a google search for very similar behaviours.

I've been deploying a pattern of Cisco WAP121 (up to 4 in single-point-setup), Cisco SG200 and Billion 7800xx router (DX, X, VDOX).  I've just finished deploying about 15 venues/pubs that I'm tasked with looking after - including using the same setup at home - never had an issue...

... until I did the same setup for my father's house.

His ADSL would get him 6Mb/s down and 0.9Mb/s up regularly.  But with the new WAP121's in (2 of) he would (after a few hours of use, or randomly) end up getting 0.21Mb/s down and the same outbound.

Swapped out WAP121s and had the same issue.

Updated MTUs on the router.

Was about to try a 4G dongle in his router to rule in/out the ISP, but forgot to take home the 4G USB stick from work.

So, instead, unplugged 1 access point, and ran the 2nd access point on a different physical cable (just a long patch lead).

Turns out the cabling or terminations must be just "broken" enough to give the behaviour above.

Put the 2nd access point back into play (at the other end of the house) and it's all ok.

So... never rule out that you've just got some crappy cabling/termination going on!  (this cable was tested with the usual network cable tester that tells you pin 1 = pin 1, etc, etc).

[Martijn van Dijck]

It was not the cable.

I tested it also with no switches or hubs direct connected to the router from the ISP.

It must have something to do with the MTU on the router from the ISP. As an home user I Cannot change this settings on this device.

[abacusadm]

Hello,

I wished i had read this post before I bought 4x WAP121's

So I have them, I have all the problems seen in this post mainly slow network speeds.

I have Cisco Catalyst 3750 Switches and Cisco ASA 5512's.

Default VLAN(1) tagging and no VLAN setup on WAP's

Is anyone willing to pick this up and start trouble shooting with me.

WAP's are on latest firmware. 

Tried in cluster and out

Tried N and no N

Something I haven't seen on  this post is the Single Point Access cluster, sometimes i get two devices sometimes three but its up and down.

Damian

[abacusadm]

Also devices are set to 100 Full Static this definitely makes a difference.

The devices are set up in small office about 150 meter squared dotted around in each corner.

SSID is the same on all devices running on different channels at 20/40

Device details:

Unit 1:

Channel: 1

wlan0 noise: -83
wlan0 utilization: 38

Unit 2:

Channel: 5

wlan0 noise: -85
wlan0 utilization: 33

Unit 3:

Channel: 9

wlan0 noise: -78
wlan0 utilization: 34

Unit 4:

Channel: 13

wlan0 noise: -79
wlan0 utilization: 36

[abacusadm]

How is this marked as solved when the answer was to minimize the functionality?

[CoralSys]

Hi,

I've been fighting this a long time, and the discussion here shed some light on the issue, so I wanted to share my findings, too:

Disabling 802.11n obviously improves the situation, but is more heavy-handed than what seems necessary. My workaround originates from staring for a long time on the rate indicator in the Windows connection status while changing radio settings, which might not be the most sophisticated approach. But I'm quite confident now that the actual problem is the variety of rate sets that the AP advertises in its default configuration. They make the connection jumping between these settings a lot, and also being degraded to an extent that is probably not necessary based on the actual radio conditions.
The radio config that I'm running now with good results:

Mode:
2.4 GHz 802.11n
Channel Bandwidth:
20 MHz (40 is not necessary - see explanation below - and also not usable with my devices in combination with the other settings)
Primary Channel:
Lower
Channel:
x (based on your environment)
Advanced Settings
Short Guard Interval Supported:
No (probably helpful)
Protection:
Off (maybe not necessary)
Beacon Interval:
100 (default)
DTIM Period:
2 (default)
Fragmentation Threshold:
2346 (default)
RTS Threshold:
2347 (default)
Maximum Associated Clients:
200 (default)
Transmit Power:
Full - 100% (default)
Fixed Multicast Rate:
Auto (default)
Legacy Rate Sets:
Only 54 Mbit/s checked in Supported and Basic, uncheck everything else in Supported and Basic
MCS (Data Rate) Settings:
Only indices 5, 6, 7, 11, 12, 13 enabled, disable everything else
Broadcast/Multicast Rate Limiting
Disabled (default)
TSPEC Mode:
Off
TSPEC Voice ACM Mode:
Off
TSPEC Voice ACM Limit:
20 (default)
TSPEC Video ACM Mode:
Off
TSPEC Video ACM Limit:
15 (default)
TSPEC AP Inactivity Timeout:
30 (default)
TSPEC Station Inactivity Timeout:
30 (default)
TSPEC Legacy WMM Queue Map Mode:
Off

The Legacy Rate Set is configured under the assumption that I don't need differentiated b/g support.

The MCS indices are selected from this useful table: http://mcsindex.com/

Based on its specs, the WAP121 can operate anywhere in the "HT" indices 1-15 and in the left four sub-columns of the column "OFDM (Prior 11ax)", basically the light yellow area. However, since we have only a 100 Mbit/s ethernet uplink, the 20 MHz bandwith should be enough, reducing it to the left two columns. The speeds that I read on my devices match the left column for "0.8µs GI", so I disabled the Short Guard Interval. Now it's only about the indices. Because of the ethernet limit, I unchecked 14 and 15. On the other hand, I don't think I need something down in the b/g speed range, so 52 Mbit/s is my lowest n speed by picking 5-7 and 11-13.