Nope, they do not drop ip and get the invalid address. They actually keep their ip info. What's happening is I'm dropping out of the ARP table of our router, because the AP has decided to block it via the Broadcast control mechanism of the Access Point. We operate the wireless on top of the wired network. So an access point on the student network will not block arp's from the router of its network. but if a laptop from another network uses the access point, the access point will block arps coming from THAT router. Obviously a segregation of the wireless network would solve this, but still a weird problem.
-----Original Message----- From: 802.11 wireless issues listserv [mailto:[EMAIL PROTECTED] Behalf Of Jonn Martell Sent: Saturday, November 08, 2003 9:19 PM To: [EMAIL PROTECTED] Subject: Re: [WIRELESS-LAN] Broadcast Limiting in Avaya Access Points (was dropping ip) Hi Matt, We took out our Lucent-based APs as part of the project but that's a little scary. So I can't comment on the exact behavior of that AP. When you say that it drops its IP, do you mean that the IP address on the client changes to invalid/169.254 ? If that is the case, I would check to see if the drop is at the DHCP mid-point pf the lease when most clients perform a renew. Unless you have DHCP server filtering on your APs, it's trivial to put up a fast rogue DHCP server that might cause havoc. Can you easily reproduce the problem? ... Jonn Martell, wireless.ubc.ca Matt Ashfield (UNB) wrote: > Hi All, > > I've been fighting a problem on campus where students laptops appear to be > dropping their ip connection to the network sporadically. I'm hoping someone > can shed some light on the situation. > I think I've narrowed it down to the broadcast limiting in the Access > Points. I was using the default threshold settings, and thinking I either > need to dramatically up them or remove them altogether. The definition in > the Avaya "documentation" (<insert your own joke here>) states: > "If the maximum value of Broadcast or Multicast per second is exceeded, the > Base Station will ignore all subsequent messages issued by the particular > network device, or ignore all messages of that type." > The default settings limit to 30 frames/sec for an address and 60 for a port > (ethernet and wireless). So what I take this to mean is, if a mac address > transmits more than 30 broadcasts/second (in our network, not unheard of), > then it gets ignored. Now, this would seem to be what his happening. Except > the problem is, the address getting blocked/ignored is the router address > (caused by an arp storm perhaps). > So my question is, once an address is ignored, what does it take to get the > access point to allow that address to be heard again? Is there a time limit? > How does this work exactly? > Any info/insight would be greatly appreciated. > > Thanks > > Matthew Ashfield > Network Analyst > Integrated Technology Services > University of New Brunswick > (506) 447-3033 > > ********** > Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/cg/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/cg/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/cg/.
