Arista Networks, Inc.
Hitless Upgrade Of Packet Processing Rules

Abstract:

Upgrading packet processing rules in a network device with a replacement set of rules includes generating an edit sequence that represents edit operations to transform an already-installed old set of rules into the replacement rules. The edit sequence is used to identify a subsequence of rules that is common to both the old rules and the replacement rules. A merged list is generated by a combination of the old rules, the replacement rules, and the common subsequence of rules. The merged list is downloaded to the network device, overwriting the old rules in bottom-up fashion allowing packet processing to continue concurrently using the old rules.