Wireless Access

Hello everyone,

I would like to learn from your expertise guys.

I will implement two controllers (only) in an enterprise, my question is which of the following configuration should I use, why and what is the main difference between each:

1- One Master and One Master redundant (active)

2- One Master and One Master redundant (standby)

3- One Master and One Local

4- One Local and One Local redundant (active)

5- One Local and One Local (standby)

Inaddition if in the same situation only two controllers will be deployed but one in campus and one in a remote site then the best design would be One Master and One Local ?

Finally, if I will have only one Controller, should I make it a Master or Local ?

Thank you very much. I hope to find a good answer from you guys.

Please consult the Aruba Mobility Controllers Validated reference design guide here:  http://www.arubanetworks.com/wp-content/uploads/VRD_Aruba-Mobility-Controllers_8.pdf  for answers to all of your questions...

More Validated Reference Design documents can be found here:  http://www.arubanetworks.com/technology/reference-design-guides/

Hi cjoseph

I am reading this document and looking through the redundancy part. But this VRD makes me create more and more question than solving and answering my questions ! :manfrustrated:

If you know so please tell me because this VRD is not organised enough and instead of going from simple just one controller up to many it start from MANY down to MANY !! 

If I have one Master and onle Local and the Master goes down will the Local become the Master ?

if in the same previous scenario the Local went down, will the Master handle and manage the AP traffic ?

When creating Master - Local configuration this mean no VRRP will be established and they will just talk through IPsec if CPsec enabled ?

from my understanding the Master can do Local's functions (based on VRD) but will the Local fucntion as Master if no master exist any more ? and based on what is there a priority value or based on the MAC address ? 

can MC work as Master and Local dpending on the need ?!

Does all of this mean that if I have a single MC, my network will not work !! because if I am using this MC as Local, AP boot fails: 

During the AP boot cycle, the AP must discover and connect to a provisioning mobility
controller. In almost all deployments this is the master mobility controller, because that mobility
controller typically is not serving APs and is able to be a single source for AP provisioning.

If the single MC working as Master then AP will not work properly because the AP will not find any local controller to associate with ?!

I strongly recommend that ARUBA describe the following in detail - how things will work in the following cases:

1- One MC in Master mode - No other Local or Master:

2- single MC in Local mode - no other Local or Master:

3- Two MC, one Master and one Local (only no more):

4- Three MC, Two Master and one Local (only no more):

5- Three MC, One Master and two Local ( only no more):

I belive once ARUBA do this every one can start scale it for their own network but not starting from 100 MC !!

cjoseph, can you descripe things here ?!  I am not the only one who will thank you.

Sorry to say all of the above, but I do not like to read something that complicate things instead of simplifiying it. That is why I came here to ask those questions because I was not able to ind the answer somewhere else.

Regards,

Abi

Abi:

Here is what I can tell you:

The smallest network that requires a controller needs a master.  The master exists for central configuration and monitoring of the network.  A master controller can terminate AP management and user traffic.

You can add a second controller to increase capacity and that second controller is known as a local.  The local controller is added by pointing it to a master controller.  The local controller then obtains the entire configuration fro the master.  The local controller can terminate AP and user traffic, but is read-only.  You cannot change any of the global configuration from this device.  If the master controller is down, you cannot change the configuration of any local controller, but local controllers will still be able to terminate user and AP traffic and authenticate users; you just cannot make any changes to the configuration.  A local can be converted to a master by changing an option and rebooting the controller, however.

To provide redundancy for the read-write master, some networks add a backup master, which is linked to the master controller  through by a master redundancy configuration.  The master redundancy is configured by establishing a VRRP between master and backup master, each with different priority.  There is also a specific config on each controller that designates the master-backup master relationship and ties it to the status of the VRRP (this relationship is established over ipsec).   The controller with the higher priority becomes the master; the other controller with the lower VRRP priority becomes the backup master.    The backup master can take over if the master controller is down and provides read-write configuration, as well.  The backup master cannot actively terminate AP or user traffic when there is currently an active master.  When the master controller is down, the back up master takes over and can terminate AP and user traffic.

Every network is different, so please let me know if you have any further questions.

hi cjoseph,

Thank you for your time, I would like to make this more interesting and to know more about the knowledge and deployment, quick questions:

1- The network with Mobility Controllers SHOULD have at least one master controller, and the network can not work with only Local controllers. ( Unless you started one local as master to load configuration to other MC then switched it to local again).

2- in Master (Active) - Master (Standby) , scenario:

     A- I need to configure both masters because the standby master will not take configuration from the active and they will not syncronize with each other unless I have AWMS. however, they synchronise database and RF Plan manually or automatically.

  B-  I can not have - Master ( Active ) - Master ( Active).

3- In Master - Local scenario:

a- Can I make redundancy between the Master and Local ? using VRRP ? (e.g. the comming point)

b- If the Local goes down will the Master takeover and terminate the AP, and when Local come up it will takeover and terminate AP ? ( I belive the answer is yes if we eable preempt capability).

c- The main advantage of Master-Local is to minimze configuration, management and troubleshooting.

d- If the Master is not full to its maximum AP capacity and you have a new building, we can add new Local MC to manage new AP, however, if it is full we then need new Master MC.

4- Do we consider a single M3 blade a controller or the whole chassie (even with 4 M3 blades) will be considered controller ?

e.g. If I have 6000 MC with four M3 blades, does this mean I can have 4 Controllers inside a single 6000 chassie (regardless of Master/Local Configuration) ?

5- If I have 12 AP and one 6000 MC and one 620 Controller ... an implementation of 6000 as Master and 620 as local can not be done because 620 local can not handle 12 AP (its max is 8). therefore, the other local controllers can determine the need of new Master controllers or a replacement of existing Local Controllers. 

6- I can use both configurations (Master/Local) or (Master/Master) but it final choice depend on scalability issues, physical location, type of equipment and ease of configuration and personal choice, is not it ?

Thank you again :-) start feeling better when I start to understand.

Please see my answers <INLINE>:

@Abi wrote:

hi cjoseph,

 

Thank you for your time, I would like to make this more interesting and to know more about the knowledge and deployment, quick questions:

 

1- The network with Mobility Controllers SHOULD have at least one master controller, and the network can not work with only Local controllers. ( Unless you started one local as master to load configuration to other MC then switched it to local again).

 <1.  Network cannot work without a master controller, because that is what configures the system.>

 

2- in Master (Active) - Master (Standby) , scenario:

     A- I need to configure both masters because the standby master will not take configuration from the active and they will not syncronize with each other unless I have AWMS. however, they synchronise database and RF Plan manually or automatically.

  B-  I can not have - Master ( Active ) - Master ( Active).

 <The standby master, when configured as such, will get the entire config from the master.  You do NOT need AWMS to manage configuration, at all.  You can optionally nfigure the local database and RF plan to synchronize between master and backup master using the "database synchronize" configuration command.

 

3- In Master - Local scenario:

a- Can I make redundancy between the Master and Local ? using VRRP ? (e.g. the comming point)

b- If the Local goes down will the Master takeover and terminate the AP, and when Local come up it will takeover and terminate AP ? ( I belive the answer is yes if we eable preempt capability).

<a.  Yes.  b.  yes, with Preempt

c- The main advantage of Master-Local is to minimze configuration, management and troubleshooting.

<The main advantage of master-local is to increase AP capacity>

 

d- If the Master is not full to its maximum AP capacity and you have a new building, we can add new Local MC to manage new AP, however, if it is full we then need new Master MC.

<If master is full, you can add as many local MC as you need.  You only require one master and you can add only locals to add capacity, if you want.>

 

 

4- Do we consider a single M3 blade a controller or the whole chassie (even with 4 M3 blades) will be considered controller ?

e.g. If I have 6000 MC with four M3 blades, does this mean I can have 4 Controllers inside a single 6000 chassie (regardless of Master/Local Configuration) ?

<Yes.  4 Controllers, yes.  The 4 controllers can be configured in any combination--They only share power in the chassis>

 

5- If I have 12 AP and one 6000 MC and one 620 Controller ... an implementation of 6000 as Master and 620 as local can not be done because 620 local can not handle 12 AP (its max is 8). therefore, the other local controllers can determine the need of new Master controllers or a replacement of existing Local Controllers. 

<You can do this, by using separate AP groups that point to separate controllers.  For example 6 APs can be in ap-group 1 which points to the 620 and 6 APs can be in ap-group 2 which points to the 6000>

 

6- I can use both configurations (Master/Local) or (Master/Master) but it final choice depend on scalability issues, physical location, type of equipment and ease of configuration and personal choice, is not it ?

<Capacity and Redundancy are probably the biggest factors.  An extreme example is that some of the largest networks would use two 3600 controllers, one for master, one for backup master and M3s as locals.  The 3600 would not have any APs on them but would redirect APs that are sent to them to any number of downstream local controllers.  The actual APs would terminate on the M3s as locals.  The 3600s would back each other up, in that if one is down, you would still be able to configure your network on the fly>.

 

Thank you again :-) start feeling better when I start to understand.

 

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