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Occasional Contributor II

AP's bouncing between "up" and "down"

Good day.  A customer recently connected Aruba AP's to the network in preparation for provisioning.  What appears to be happening is that the AP's will show up in the default group as "up" and after couple minutes the will show as "down".  They keep bouncing between "up" and "down". The network is configured to provide IP addresses to the AP's via DHCP and there are two IP helper addresses configured on the AP management VLAN.  I am not exactly sure how these DHCP servers are configured to handle DHCP requests (split scope etc.).  As per the attached document I am seeing that there are two AP's in the database with the same IP address and i see one mac address with two different IP addresses.  Additionally, in the same attachment, I've attached a couple log entries.  I am suspecting a DHCP issue.  Does this sound about right?  Thanks in advance.

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Contributor II

Re: AP's bouncing between "up" and "down"

In the log, the MAC address is being swapped.

The AP's should be served by a unique DHCP serer.

 

Is this in an INSTANT configuration?

 

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Occasional Contributor II

Re: AP's bouncing between "up" and "down"

Thanks for the reply Shieva.  No, this is not an Instant AP configuration; this is a wireless controller based network.  Out of curiosity, how, or why, is the mac-address being "swapped"? Could this be due to one or both of the DHCP servers not being configured correctly?  I know there are two IP helper addresses configured on the Layer 3 VLAN.  The way I understand it, the client DHCP request from the AP is forwarded to the first configured IP helper address.  The second IP helper address is the "backup" DHCP server should the first one not be online. Other than the standard information configured for a DHCP scope and option 43 (ip address of the master controller) and option 60 (ArubaAP).  I believe two DHCP servers are configured to provide fault tolerance and possibly some load balancing but I may have to ask the server folks more about the DHCP configuration as I suspect something is not configured correctly.  It's just weird how mac-addresses are being "swapped". 

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Occasional Contributor II

Re: AP's bouncing between "up" and "down"

Thanks for the reply Shieva.  This is not a Instant AP, it is a controller based network.  I am just curious how, or why, the mac-address for an IP address is being "swapped".  Could it be "swapped" due to the two DHCP servers processing the DHCP request (possibly duplicate IP's).  I know two DHCP servers are used for fault tolerance and possibly some load balancing.  The standard IP information is configured for the DHCP scope and options 43 and 60 (ip address of master controller and ArubaAP).  I may have to ask exactly how these two DHCP servers interact with each other and process DHCP requests because I suspect that something is not configured correctly.  This sound about right?

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MVP Guru

Re: AP's bouncing between "up" and "down"

Can you try disabling DHCP servers till you only have a single DHCP server? I suspect there are indeed two or more DHCP servers that are issuing IP addresses from the same scope.

 

If you need multiple DHCP servers on the same subnet, make sure their lease pools are non-overlapping, so each of them will have a unique range of IPs to assign to prevent duplicated IP assignments.

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