Controllerless Networks

Hi guys,

My customer wants to test the L3 mobility functionality in his Instant cluster, so he wants to make to clusters, where there are two VC in differents subnets, but the users segments are the same, something like this (simplified):

I have read about L3 mobility configuration in the Instant user guide, but it is not very clear. For this topology, can you confirm the configuration for VC 172.18.5.1 will be something like this?

And I understand the configuration for VC 172.18.6.1 will be the same, just changing IP 172.18.5.1 for 172.18.6.1. Is that OK? I have never configured L3 mobility, please your help.

Regards,

Julián

Have a look at this link, it should help you.

https://community.arubanetworks.com/t5/Controller-less-WLANs/How-does-L3-Mobility-work-in-Instant-AP/ta-p/267166

The VLANs shouldnt exist on both sides.

Hi Shieva,

I already checked that post, but it is not clear since the VLANs and subnets in the picture don't match with those in the configuration, and that's the reason of writing this post. And what do you mean with "The VLANs shouldnt exist on both sides."?

Regards,

Julián

The picture is a bit misleading, use the sw outputs.

The point of L3 mobility is to create a GRE tunnel between 2 different VC's when the client roams off of their AP.

In principle, when the client moves from one AP to another AP, the recieving AP would create a GRE tunnel back to the original AP creating a tunnel to pass the traffic.

The SSID's are on separate VLANs.

The switchports can have the same VLANs as indicated in the sw outputs.

This post has some more details:

https://www.arubanetworks.com/techdocs/Instant_40_Mobile/Advanced/Content/UG_files/L3_mobility/Configuring_a_mobility_d.htm

Yes, I also read that, it is the same as that on the Instant user guide. According to that I think the config I showed is OK, I only wanted a confirmation because I am not sure. What my customer wants is to test to have two clusters of IAPs, because he has sites with around 200 APs, so better to have two clusters in those sites, but he wants to test first in a lab (just one switch), and I have to make the configuration.

The only thing is the users' VLANs and subnets in the two clusters are the same as showed, so the users are not going to change their IP when roaming between the clusters. Then I don't know if in this case I have to configure L3 mobility as showed, or just to create two clusters of IAPs without L3 mobility (since users' VLANs are the same in both clusters). Does it make sense?

Regards,

Julian

Creating 2 VC's will cause the client to drop when leaving one mobility domain.

If the client reconnects back, they should be getting the same DHCP configuration from the target VC, since you're leaving all the VLANs and configuration the same.

To simplify your config, the SSID has to appear on all VCs, it just

shouldn't be on the same VLAN...

Any network traffic on the same VLAN is L2 traffic.

To answer your initial question, yes, your VC config appears to good.

According to this post I can do it without configuring L3 mobility, I have the same situation:

https://community.arubanetworks.com/t5/Controllerless-Networks/IAP-and-Multiple-Cluster-Deployment-same-core-switches/td-p/457958

I don't know why the VLANs' SSIDs must be different between clusters if I can place them on the same VLANs, the only limitation is the number of APs in one cluster.

I will try it and let you know.

Regards,

Julian

You can that solution, but it's not L3 mobility.

The only issue with 2 different VC's in RF interference.

The client will transition between RF zones.

Again... assuming the same SSID but different VLAN's.

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@Shieva wrote:

You can that solution, but it's not L3 mobility.

 

I agree, it isn't L3 mobility.

 

The only issue with 2 different VC's in RF interference.

The client will transition between RF zones.

 

Again... assuming the same SSID but different VLAN's.

 

I will do it with same SSID and same VLANs.

 

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Will I have RF interference? Why? The ARM and Auto Channel/Power assignment is completely distributed and handled by the individual IAPs in an Aruba Instant cluster, so it will be the same if I have one cluster or two.

Regards,

Julián

This is now a new topic:

I will do it with same SSID and same VLANs.

This means that the AP's will all see each other on the wire, and the master VC will form 1 cluster, 1 VC.

This is the basis of Aruba Instant AP.

This is now assuming that all the APs have the same firmware.

Sorry, it was a misunderstanding:

I will do it with same SSID and same VLANs.

I meant same SSID with same users' VLANs, but the APs management VLANs will be different (like the picture), so I will have 2 VCs.

Regards,

Julián

All good... keep notes and let us know how you progress...

Hi,

I configured the two clusters and because the users' VLANs were the same in both of them I didn't need to configure L3 mobility.

I run a continuous ping and start roaming intracluster and intercluster. In 2.4GHz one packet was lost in every roaming event between APs in both cases, but I believe it was because there was seven APs in a small site and therefore much CCI. I did the same test in 5GHz and the roaming was transparent with no packet loss in both cases (intracluster and intercluster roaming).

Regards,

Julian