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Hi all hope you can help.

Our Psion handheld devices used in the warehouse have been renewing their DHCP leases every time they change AP on our Aruba network. I have spoken to Psion and they say it is an AP configuration issue, rather than the handhelds.

The DHCP server on which they renew their IPs is on a separate subnet and sometimes we have to either take the link down, or reboot the DHCP server. This causes all handhelds to stop working as soon as they move to new AP which should not be happening as they are on an 8 day lease.

All APs and clients are on the same subnet and get their IPs from the same DHCP server.

Psion told me the following:

I have analyzed your issue and as well I have consulted my colleagues from the Motorola wireless support and we think that the issue can’t be cause from the client’s side (the EP10) and we believe this would be a configuration issue with the AP’s. Further to this, when the AP’s are set up to be transparent (as we have them in the office, then once every few hours, minutes, depending on how they were set up, they will check with the server if the same IP is still available and will continue using it, without refreshing it) , but when they are not set up as transparent, then they will act like a router and then the IP will be renewed while the client will switch from one AP to another.

I cant find anything in the configuiration that seems to fit this explanation? Can anybody suggest anything?

The access points are Aruba IAP-104.

Thanks for your help.

  • Which version of code are you IAP-104's running? Which one is operating as the "Master" or "Virtual Controller"? Are all the IAPs joined to the Master IAP properly? – YLearn Oct 16 '14 at 21:32
  • @YLearn Version is 6.2.1.0-3.3.0.2_38733. Our virtual controller IP is 10.0.1.2, with 10.0.1.76 being the master. I can see all 25 AP's when I log into both the virtual controller and the master. Thanks. – scampbell Oct 17 '14 at 7:16
  • What did the folks at Aruba say? – Ron Royston May 14 '15 at 23:18
  • @RonRoyston They said we want money as your support contract has expired. I no longer work for the company so I guess i will never know the answer to that question. – scampbell Jun 25 '15 at 12:31
  • Unfortunately, questions about protocols above OSI layer-4 are explicitly off-topic here. You could try to ask this question on Server Fault for a business network, or on Super User for a personal network. – Ron Maupin Aug 10 '17 at 19:05
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dear i faced same problem but with 3rd party AP not aruba .taking into consideration our handheld can be connected wired and wireless, after alot of analysis we found that those handhelds generate huge multicast (icmp , TCP and UDP) traffic cause even switch CPU% increase to unusual percentage. the only work around solving this case , isolate handheld devices in separate vlan with separate DHCP scope with separate SSID ,may you configure your controller to be its DHCP server for this vlan .

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If the AP is a bridge, then it's not involved in the DHCP transaction. In all cases, it's up to the client as to when it renews or rebinds. If I had to guess, the Psions are resetting when they "roam" because the link is getting reset. (almost all systems will restart DHCP ("rebind") if the link state changes.) That said, even if they are rebinding, it shouldn't matter much, as the DHCP server should prefer to give it the same address it already has.

You'll need a fully integrated wireless network (read: wireless lan controller) to get the APs to signal clients to move between APs vs. the client choosing when it moves into/out of range.

  • The Aruba AP's have a virtual controller which should take care of everything. It normally isnt a problem when they renew their lease every AP change since as you say, they keep the same IP address. The problem arises if the link to the DHCP server subnet is down, or the DHCP server is down itself - they all stop working pretty much straight away as they are looking to renew their IP as soon as they change AP. Thanks. – scampbell Oct 17 '14 at 7:18

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