Layer 3 Mobility; Configuring Layer 3 Mobility - Extreme Networks Summit WM3000 Series Reference Manual

Controller Services
4 On the Configuration tab, check the Enable Redundancy checkbox and then check the Enable Cluster
GUI box.
5 Click the Apply button to enable the Cluster GUI feature.
6 Once Cluster GUI is enabled a Controller field will be available in many of the Access Point and
mobile unit related screens. The Controller field is displays which cluster members the APs and MUs
are associated with identified by their IP address.
NOTE
When accessing the controller Web UI through a NATed interface the Cluster GUI features will only be accessible
if TCP ports 80 and 161 are opened on the router or gateway.

Layer 3 Mobility

Refer to the following sections to configure Layer 3 Mobility:

"Configuring Layer 3 Mobility"

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"Defining the Layer 3 Peer List"
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"Reviewing Layer 3 Peer List Statistics"
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"Reviewing Layer 3 MU Status"
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Configuring Layer 3 Mobility
Layer 3 mobility is a mechanism enabling a MU to maintain the same Layer 3 address while roaming
throughout a multi-VLAN network. This enables transparent routing of IP datagrams to MUs during
their movement, so data sessions can be maintained while they roam (in for voice applications in
particular). Layer 3 mobility maintains TCP/UDP sessions in spite of roaming among different IP
subnets. Layer 3 mobility is supported only for extended WLAN traffic, not for the independent WLAN
traffic.
A mobility domain comprises of a network of controllers among which an MU can roam seamlessly
without changing its IP address. Each controller in the mobility domain needs a mobility domain string
identifier so MUs roaming between controllers can retain their Layer 3 address and maintain
application-layer connectivity.
When a MU enters a mobility domain (by associating with a controller), it is first assigned a home
controller. The home controller is responsible for assigning a VLAN for the MU and communicating the
MU's mobility-related parameters to the other controllers in the mobility domain. The home controller
does not change for the remainder of the MU's presence in the mobility domain. All data packets
transmitted/received by the MU including DHCP and ARP are tunneled through the home controller.
The IP address for the MU is assigned from the VLAN to which the MU belongs (as determined by the
home controller).
The current controller is the controller in the mobility domain an MU is currently associated to. The
current controller changes as the MU roams and establishes different associations. The current controller
is responsible for delivering data packets from the MU to its home controller and vice-versa.
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Summit WM3000 Series Controller System Reference Guide