Hitless restart mechanism for non-stop data-forwarding in the event of L3-mobility control-plane failure in a wireless switch
First Claim
1. A method for restarting a first wireless switch when the first wireless switch fails, wherein the first wireless switch comprises a control plane comprising a control plane layer 3 (L3) mobility module and a control plane wireless client database (CPWCDb), and a data plane comprising a data-forwarder module and a data plane wireless client database (KWCDb), the method comprising:
- restarting the control plane L3 mobility module of the first wireless switch, when the first wireless switch fails, and transmitting a restart message from the first wireless switch to the peer wireless switches of the first wireless switch to announce that the first wireless switch has restarted and to begin re-establishing peering sessions with peer wireless switches of the first wireless switch;
resetting a home wireless client database (HWCDb) of the first wireless switch with the information from the KWCDb, and transmitting a first message from the first wireless switch to peer wireless switches of the first wireless switch, wherein the first message comprises the information in the HWCDb of the first wireless switch;
receiving, at the peer wireless switches, information in the HWCDb of the first wireless switch, storing the information from the HWCDb of the first wireless switch in respective CPWCDbs of the peer wireless switches, and initially marking the wireless client devices in the respective CPWCDbs of the peer wireless switches as stale entries;
exchanging information from respective home wireless client databases (HWCDbs) of each peer wireless switch with the first wireless switch as a peering session is established between the first wireless switch and that peer wireless switch, wherein each respective HWCDb comprises the set of wireless client devices for which the particular peer wireless switch is the home wireless switch;
refreshing the CPWCDb of the first wireless switch and the KWCDb of the first wireless switch with updated information about each of the wireless client devices in the mobility domain such that the CPWCDb of the first wireless switch and the KWCDb of the first wireless switch are synchronized with information from the respective HWCDbs of the peer wireless switches, and transmitting the updated HWCDb of the first wireless switch to the peer wireless switches; and
refreshing stale entries in the respective CPWCDbs of the peer wireless switches with the updated information from the updated HWCDb of the first wireless switch such that the respective CPWCDb of the each peer wireless switch and the respective KWCDb of each peer wireless switch are synchronized with the updated HWCDb of the first wireless switch.
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Accused Products
Abstract
Techniques and technologies are provided for restarting a first wireless switch when the first wireless switch fails. For example, after the first wireless switch fails, the first wireless switch transmits a restart message to its peer wireless switches to begin re-establishing peering sessions with peer wireless switches. The first wireless switch resets its home wireless client database (HWCDb) with information from its data plane wireless client database (KWCDb), and transmits the updated information in its HWCDb to its peer wireless switches. The peer wireless switches store this information in their respective control plane wireless client databases (CPWCDbs), and initially mark the wireless client devices in the respective CPWCDbs as stale entries. Each of the wireless switches then exchanges information from their respective HWCDbs with the first wireless switch (and other peer wireless switches) so that each wireless switch eventually has a wireless client database (WCDb) comprising each of the wireless client devices in the mobility domain.
64 Citations
20 Claims
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1. A method for restarting a first wireless switch when the first wireless switch fails, wherein the first wireless switch comprises a control plane comprising a control plane layer 3 (L3) mobility module and a control plane wireless client database (CPWCDb), and a data plane comprising a data-forwarder module and a data plane wireless client database (KWCDb), the method comprising:
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restarting the control plane L3 mobility module of the first wireless switch, when the first wireless switch fails, and transmitting a restart message from the first wireless switch to the peer wireless switches of the first wireless switch to announce that the first wireless switch has restarted and to begin re-establishing peering sessions with peer wireless switches of the first wireless switch; resetting a home wireless client database (HWCDb) of the first wireless switch with the information from the KWCDb, and transmitting a first message from the first wireless switch to peer wireless switches of the first wireless switch, wherein the first message comprises the information in the HWCDb of the first wireless switch; receiving, at the peer wireless switches, information in the HWCDb of the first wireless switch, storing the information from the HWCDb of the first wireless switch in respective CPWCDbs of the peer wireless switches, and initially marking the wireless client devices in the respective CPWCDbs of the peer wireless switches as stale entries; exchanging information from respective home wireless client databases (HWCDbs) of each peer wireless switch with the first wireless switch as a peering session is established between the first wireless switch and that peer wireless switch, wherein each respective HWCDb comprises the set of wireless client devices for which the particular peer wireless switch is the home wireless switch; refreshing the CPWCDb of the first wireless switch and the KWCDb of the first wireless switch with updated information about each of the wireless client devices in the mobility domain such that the CPWCDb of the first wireless switch and the KWCDb of the first wireless switch are synchronized with information from the respective HWCDbs of the peer wireless switches, and transmitting the updated HWCDb of the first wireless switch to the peer wireless switches; and refreshing stale entries in the respective CPWCDbs of the peer wireless switches with the updated information from the updated HWCDb of the first wireless switch such that the respective CPWCDb of the each peer wireless switch and the respective KWCDb of each peer wireless switch are synchronized with the updated HWCDb of the first wireless switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A network of peer wireless switches in a first mobility domain, comprising:
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a first wireless switch in the first mobility domain, wherein the first wireless switch comprises; a first processor comprising a control plane layer 3 (L3) mobility module configured to restart after the first wireless switch fails; a first transmitter configured to transmit a restart message to the peer wireless switches of the first wireless switch to announce that the first wireless switch has restarted and to begin re-establishing peering sessions with the peer wireless switches; a first database comprising a first control plane wireless client database (CPWCDb), a first data plane wireless client database (KWCDb), and a first home wireless client database (HWCDb) configured to store a set of wireless client devices for which the first wireless switch is the home wireless switch, wherein the first HWCDb is reset with the information from the first KWCDb upon restart of the first wireless switch, wherein the transmitter is configured to transmit a first message to the peer wireless switches, wherein the first message comprises the information in the first HWCDb after it is reset; a first receiver; wherein each peer wireless switch comprises; a respective receiver configured to receive information in the HWCDb of the first wireless switch; a respective control plane wireless client database (CPWCDb) configured to store the information from the HWCDb of the first wireless switch, and initially mark the wireless client devices in the respective CPWCDb as stale entries; a respective processor; a respective home wireless client database (HWCDb) configured to store a set of wireless client devices for which the particular peer wireless switch is the home wireless switch; a respective transmitter configured to transmit information from the respective HWCDb to the first wireless switch and any other peer wireless switches when a peering session is established between the first wireless switch and that particular peer wireless switch; wherein the respective receiver is configured to receive information from the respective HWCDbs of each the other peer wireless switches and the first wireless switch, wherein each respective HWCDb comprises the set of wireless client devices for which the particular peer wireless switch is the home wireless switch a respective data plane wireless client database (KWCDb); and wherein the first receiver is configured to receive information from the respective HWCDbs of each the other peer wireless switches, and wherein the first CPWCDb and the first KWCDb are configured to be refreshed with updated information about each of the wireless client devices in the mobility domain such that the first CPWCDb and the first KWCDb are synchronized with information from the respective HWCDbs of the peer wireless switches, and wherein the first transmitter is configured to transmit the updated HWCDb of the first wireless switch to the peer wireless switches; and wherein each of the respective receivers is configured to receive the information in the first HWCDb after it is reset, and the information from the respective HWCDbs of each the other peer wireless switches; wherein each of the respective processors is configured to refresh stale entries in its respective CPWCDb with the updated information from the first HWCDb such that the respective CPWCDb and the respective KWCDb are synchronized with the first HWCDb. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification