Technical data

Chapter 14

Intercontroller Roaming

When a wireless client can maintain connection from one AP to another, this is

roaming. When a client can roam between APs on different controllers on different

IP subnets without losing its IP address, roaming becomes inter-controller roaming.

Meru Networks’ Intercontroller Roaming feature (ICR) provides IP-IP tunnel-based

routing between a group of controllers (a roaming domain) to support IP address

mobility for stations. The feature works only if member controllers in a roaming

group spans at least two distinct IP subnets. This feature is hence targeted for

deployments with a routed network between controllers.

With ICR, a static or DHCP-provisioned IP address of a station remains routable into

an Anchor (home) controller while the station roams between other (serving) control-

lers in the roaming group.

With this feature, the upstream traffic for a client is tunneled to the Anchor

Controller, and the downstream traffic is handled by the Guest Controller.

Intercontroller Roaming supports controllers configured in a group of up to 30 Meru

controllers (a roaming domain) that is configured with CLI commands to support ICR.

At least one controller must be in an IP subnet distinct from the rest; this feature

does not work when all controllers of a roaming domain are on the same link.

Controllers must have the same SSID and identical security profiles for those SSIDs

spanning the roaming domain. (There can be additional SSIDs local to individual

controllers.) ICR can be established between two or more controllers so that the

feature activates as long as they have at least one shared ESSID where the subnet

bound to the ESSID differs between at least the two controllers.

How Inter-Controller Roaming Works

Intercontroller roaming retains stations’ IP addresses by forwarding packets via a

dedicated point-to-point tunnel between controllers, using

UDP port 9394. Then, a

user can roam between supported Meru controllers in the same domain without

disconnection or a change of IP address. Any mix of up to 30 supported controller

models is supported by ICR. Captive Portal context transfer and multicasting are not

supported by ICR.