Hey, I remember that bug! Or at least a very similar one.
There were a wide range of centrino chipsets with a driver bug. Specifically, the driver would advertise 3 stream data rates, even though the hardware itself was only 2 stream. This meant that the card could *usually* process broadcast packets, as they get sent at the greatest common denominator speed of all associated stations, so could get an IP address and ARP, but any unicast traffic would get sent at a data rate the client hardware couldn't decode and disappeared. The fix was to get a new driver from Intel, as MS update was shipping buggy drivers for a very, very long time.
The fact that the client getting an IP address depended on the data rates of other clients on the same AP made troubleshooting nearly impossible, until we got lucky and Trapeze identified it as a known bug.
Frank Sweetser fs at wpi.edu | For every problem, there is a solution that Manager of Network Operations | is simple, elegant, and wrong. Worcester Polytechnic Institute | - HL Mencken On 6/21/2016 12:06 AM, Anthony Croome wrote:
Exactly, use 24Mbs to avoid weird behaviour. We looked at this a few years ago and found that XP could not handle management packets being sent at 48Mb/s or 54Mb/s despite the card connecting at 450Mb/s on 5GHz N or 144Mb/s on 2.4GHz N. On 5GHz the laptop could get an IP address but could not ping it's gateway. On 2.4GHz the laptop could get an IP, it could ping it's gateway, but it's performance was terrible. What we saw from a 5GHz packet capture was the AP continuously sending RTS to the client but never getting any packets from the client. On 2.4GHz it would reply but only after a random number of RTS were sent. Anthony IT Networks Queensland University of Australia -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Jason Cook Sent: Tuesday, 21 June 2016 11:20 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 802.11b data rates disabled? Yeah my understanding is that as per the standard devices are required(mandatory) to support 6,12,24 rates for 802.11g. So to ensure all devices are happy then 24 would be the right minimum, therefore you may see some weird behaviour. So devices need to support that to be compliant, I'm not sure it means you have to use it. I'd say if your running 54 and there's no complaints.... why change. it will be interesting to see how things go. We disabled 802.11b rates about 3 months back with no issues reported. We've left it enabled in some of our remote campuses where we use lower rates to get distance. -- Jason Cook Technology Services The University of Adelaide, AUSTRALIA 5005 Ph : +61 8 8313 4800 -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Chuck Enfield Sent: Tuesday, 21 June 2016 6:21 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 802.11b data rates disabled? Rick, If I were brave enough to do what you've done, here's what I would worry about: - 802.11a/g devices are getting scarce, but I've heard rumors that there were 802.11g devices that required a basic rate of 6, 12, or 24 Mb/s. It's possible that there are no such devices left, that driver updates have eliminated the limitation, or that no such devices ever existed. - Many client device drivers do unexpected things when connected to networks with unconventional settings. For example, will clients with a marginal MCS 7 connection probe for their next AP before their retry rate goes through the roof? - We use 40Mhz channels, so reliable comm at MCS 7 requires about 28 dB SNR. It could be very difficult to maintain that while moving. - Even if clients roam successfully, you'll see an increase in roaming activity. Moving clients may normally hit every second or third AP along the way, in your case they'll probably hit every AP. This could increase the overhead consumed by authentication and/or stress your AAA infrastructure. That said, the AAA load could be more than offset by reduced authentication attempts to indoor APs from outdoor passers-by. I'm not suggesting these are reasons not to do it. They're just things I'd worry about. I'd be interested in hearing how it works out for you if you find the time to follow up. Thanks, Chuck -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Rick.Decaro Sent: Monday, June 20, 2016 2:10 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 802.11b data rates disabled? It sound like a lot of people have already disabled the 802.11b data rates. That being said....what minimum rate is everyone using? We just changed ours last week from a minimum of 1Mbps to 54Mbps. So far we have not heard of any issues. Does anyone know what if any problems could arise from this being set to 54Mbps? Is there a sweet spot in between that is better? Thanks, Rick DeCaro (636)230-1911 rick.dec...@logan.edu -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Watters, John Sent: Monday, June 20, 2016 1:01 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] 802.11b data rates disabled? We have had the b rates disabled for 2 months short of 5 years. Not a single complaint that I am aware of. -jcw John Watters The University of Alabama Office of Information Technology 205-348-3992 -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Todd M. Hall Sent: Monday, June 20, 2016 10:50 AM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: [WIRELESS-LAN] 802.11b data rates disabled? Do you have all of the 802.11b data rates disabled? If so, how long have they been disabled? Did you have many complaints when you disabled them? Were there any particular devices that could not connect as a result? I'm hoping this information will help us move towards disabling these old rates. Thank you for your feedback. -- Todd M. Hall Sr. Network Analyst Information Technology Services Mississippi State University t...@msstate.edu 662-325-9311 (phone) ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.