Patent ID: 8266235
Filing Date: 2012-09-11
Classification: G06F,H04L

Abstract:
1. A method for electing a master blade in a virtual application distribution chassis, the virtual application distribution chassis comprising a plurality of blades, comprising: (a) sending by each blade of the plurality of blades a virtual application distribution chassis message to each of the other blades in the virtual application distribution chassis; (b) determining by each blade whether the virtual application distribution chassis message was received from the master blade within a predetermined period of time; (c) in response to determining that the virtual application distribution chassis message was not received from the master blade within the predetermined period of time, sending a master claim message by each blade to each of the other blades in the virtual application distribution chassis, each master claim message comprising a blade priority and a blade identity for the sending blade; (d) determining by each blade receiving the master claim messages whether any of the blade priorities obtained from the received master claim messages is higher than the blade priority of the receiving blade, comprising: (e) in response to determining that the blade identity of the given receiving blade is numerically smaller than the blade identities obtained from each of the other received master claim messages, setting a status of the given receiving blade to a new master blade; (f) in response to setting the status of the given receiving blade to the new master blade, sending by the given receiving blade a second virtual application distribution chassis message to the other blades in the virtual application distribution chassis, the second virtual application distribution chassis message indicating the status of the new master blade of the given receiving blade; (g) assigning a first blade of the plurality of blades as an active blade to a virtual address, and assigning a second blade of the plurality of blades as a backup blade to the virtual address, wherein the plurality of blades are operatively coupled as the virtual application distribution chassis within a data network, the data network comprising a network switch, wherein service requests destined for the virtual address are sent to the first blade by the network switch; (h) determining by each blade that the virtual application distribution chassis message was not received from the first blade within the predetermined period of time; (i) in response to determining that the virtual application distribution chassis message was not received from the first blade within the predetermined period of time, changing a status of the second blade to the active blade for the virtual address; and (j) sending a virtual address change message to the network switch to inform the network switch to send future service requests destined for the virtual address to the second blade.