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US 8,134,969 B2Granted
IP layer-handoff using mobility domains and IP caching
AssigneeMotorola Solutions, Inc.
InventorMichael F. Korus
Life of this patent
Estimating the term…
Abstract
The disclosure relates to fast roaming techniques which can reduce L3 handoff delay when a mobile access point and/or a mobile host roams back to a previously visited subnet. These fast roaming techniques can allow the mobile access point and/or the mobile host to skip a lengthy DHCP exchange when loading an IP address thereby reducing L3 handoff delays.
Claims14
A method for fast roaming of a mobile access point, comprising in the mobile access point:
- storing internet protocol (IP) addressing information associated with a first subnet in a cache;
- receiving a beacon transmitted from the first subnet when the mobile access point roams back to the first subnet from a second subnet, wherein the beacon comprises a subnet identifier associated with the first subnet and provides L2 WLAN information;
- using the subnet identifier to determine whether the cache includes an entry for the first subnet when the mobile access point has previously established an IP address in the first subnet;
- and
- loading the IP addressing information associated with the first subnet from the cache into an IP stack
- establishing, at the mobile access point, a layer 2 security association with an infrastructure access point in the first subnet using cached security information that had been previously stored;
- and
- establishing, at the mobile access point, a route to the infrastructure access point in the first subnet.
5 more elements
A method for performing a handoff from a first subnet to a second subnet when a mobile access point roams from the first subnet to the second subnet, the method comprising:
- receiving a beacon transmitted from an access point in the second subnet, wherein the beacon comprises a subnet identifier associated with the second subnet;
- examining the subnet identifier and determining that the mobile access point has entered a new subnet;
- determining whether the mobile access point has previously established an internet protocol address in the second subnet;
- using the subnet identifier to determine whether a cache in the mobile access point includes an entry for the second subnet when the mobile access point has previously established an internet protocol address in the second subnet;
- and
- using the subnet identifier to retrieve the internet protocol address associated with the second subnet from the cache when an entry is found in the cache for the second subnet
- establishing a layer 2 security association with the infrastructure access point in the second subnet
- establishing a route from the mobile access point to the infrastructure access point.
5 more elements
Dependencies are inferred from the claim text.