Managing Router Advertisement Messages To Support Roaming Of Wireless Mobile Client Devices

A method comprising:

• at a controller configured to control one or more wireless access point devices that serve wireless mobile client devices that are part of a first virtual local area network, receiving a router advertisement message from a network router;
• determining for which of a plurality of virtual local area networks the router advertisement message is intended;
• storing the router advertisement message together with information identifying the virtual local area network to which the router advertisement message is intended;
• receiving from a wireless access point device a router solicitation message sent by a particular wireless mobile client device that is part of the first virtual local area network;
• determining to which of the plurality of virtual local area networks the particular wireless mobile client device belongs;
• determining whether there is a router advertisement message stored for the virtual local area network to which the particular wireless mobile client device belongs;
• and
• when there is a router advertisement message stored for the virtual local area network to which the particular wireless mobile client device belongs, retrieving the stored router advertisement message and sending it as a unicast message to the one or more wireless access point devices configured to serve wireless mobile client devices that are part of the first virtual local area network if the wireless mobile client device is attached to a wireless access point device controlled by the controller or to another controller that is configured to control at least one wireless access point device to which the wireless mobile client device has roamed.

An apparatus comprising:

• a network interface unit configured to send and receive messages over a wired network on behalf of a controller configured to control one or more wireless access point devices that serve wireless mobile client devices that are part of a first virtual local area network;
• a processor coupled to the network interface unit and configured to:
• receive a router advertisement message from a network router;
• determine for which of a plurality of virtual local area networks the router advertisement message is intended;
• store the router advertisement message together with information identifying the virtual local area network to which the router advertisement message is intended;
• receive from a wireless access point device a router solicitation message sent by a particular wireless mobile client device that is part of the first virtual local area network;
• determine to which of the plurality of virtual local area networks the particular wireless mobile client device belongs;
• determine whether there is a router advertisement message stored for the virtual local area network to which the particular wireless mobile client device belongs;
• and
• when there is a router advertisement message stored for the virtual local area network to which the particular wireless mobile client device belongs, retrieve the stored router advertisement message and cause it to be sent as a unicast message to the one or more wireless access point devices configured to serve wireless mobile client devices that are part of the first virtual local area network if the wireless mobile client device is attached to a wireless access point device controlled by the controller or to another controller that is configured to control at least one wireless access point device to which the wireless mobile client device has roamed.