ArubaOS and Controllers

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New Contributor
Posts: 3
Registered: ‎06-07-2011

Discovery order

Could someone knowledgable please confirm, without a shadow of a doubt, the order of operations of how an AP discovers the controller?

I'll read three different docs and interpret three different implications. I haven't been able to find a definitive source that states the step by step proccess.

Thanks,

H
Guru Elite
Posts: 20,600
Registered: ‎03-29-2007

Re: Discovery order


Could someone knowledgable please confirm, without a shadow of a doubt, the order of operations of how an AP discovers the controller?

I'll read three different docs and interpret three different implications. I haven't been able to find a definitive source that states the step by step proccess.

Thanks,

H




This is copied and pasted from the ArubaOS 6.x user guide:

Locating the Controller
An AP can discover the IP address of the controller in the following ways:
- From a DNS server
- From a DHCP server
- Using the Aruba Discovery Protocol (ADP)

At boot time, the AP builds a list of controller IP addresses and then tries these addresses in order until a controller is reached successfully. The list of controller addresses is constructed as follows:
1. If the master provisioning parameter is set to a DNS name, that name is resolved and all resulting addresses are put on the list. If master is set to an IP address, that address is put on the list.
2. If the master provisioning parameter is not set and a controller address was received in DHCP Option 43, that address is put on the list.
3. If the master provisioning parameter is not set and no address was received via DHCP option 43, ADP is used to discover a controller address and that address is put on the list.
4. Controller addresses derived from the server-name and server-ip provisioning parameters and the default controller name aruba-master are added to the list. Note that if a DNS name resolves to multiple addresses, all addresses are added to the list.
This list of controller IP addresses provides an enhanced redundancy scheme for controllers that are located in multiple data centers separated across Layer-3 networks.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Aruba Employee
Posts: 509
Registered: ‎07-03-2008

Re: Discovery order

I believe though, and this is what may cause confusion, prior to provisioning an AP (an AP is taken from its box and connected to the network), the process is:

1. DHCP option 43
2. ADP
3. DNS
Guru Elite
Posts: 20,600
Registered: ‎03-29-2007

Re: Discovery order


Could someone knowledgable please confirm, without a shadow of a doubt, the order of operations of how an AP discovers the controller?

I'll read three different docs and interpret three different implications. I haven't been able to find a definitive source that states the step by step proccess.

Thanks,

H




If you want to formulate a good approach, using DNS for all your access points to find a controller is by far the easiest thing to provision and is a best practice. To make exceptions to that, you can add the DHCP option 43 and 60 for the subnets where you want those access points to behave differently.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

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