US Patent No. 9,306,804

METHOD AND SYSTEM FOR MULTICHASSIS LINK AGGREGATION IN-SERVICE SOFTWARE UPDATE


Patent No. 9,306,804
Issue Date April 05, 2016
Title Method And System For Multichassis Link Aggregation In-service Software Update
Inventorship Kenneth J. Duda, Santa Clara, CA (US)
Roger S. Liao, Santa Clara, CA (US)
Nathan D. Arroyo, Santa Clara, CA (US)
Assignee Arista Networks, Inc., Santa Clara, CA (US)

Claim of US Patent No. 9,306,804

1. A non-transitory computer readable medium comprising instructions, which when executed by at least one processor perform
a method for performing an in-service software update (ISSU) in a multichassis link aggregation (MLAG) domain, the method
comprising:
restarting a first switch using a second version of software, wherein the first switch is currently executing a first version
of the software and the first version of the software is different from the second version of the software;

detecting by a second switch that the first switch is restarting and, in response to the detection, performing a stateful
switch-over (SSO), wherein the MLAG domain consists of the first switch and the second switch;

after restarting the first switch:
prior to the first switch performing graceful reinsertion into the MLAG domain, setting all non-peer ports on the first switch
to an error-disabled state and selecting a common MLAG protocol version supported by the first switch and the second switch;
and

performing graceful reinsertion comprising:
reestablishing a peering relationship between the first switch and the second switch using the common MLAG protocol; and
after reestablishing the peering relationship between the first switch and the second switch, synchronizing a control plane
state of the first switch with a control plane state of the second switch and setting all non-peer ports on the first switch
to an active state.