From OpenFlow Wiki

Latest revision as of 02:30, 19 October 2010

Cookie Enhancements

David Erickson - Stanford

Introduction

As a recap the cookie field currently:

• Can be set with a flow mod add, or modified with a flow mod modify
• Is returned with a flow mod expiration

In its current form there is no way to perform a stats query using the cookie field, nor to modify or delete flows based on the contents of the cookie. None of the operations require hardware support, as the cookie is not a field that is used in matching packets.

Specification changes

• Add uint64_t cookie_mask field to the ofp_flow_mod structure. When bits are set on the cookie_mask field for a flow modify or delete, then the corresponding cookie bits must be equal for the candidate flow to be considered a modify/delete match. If the cookie_mask field is 0, then flow mods behave exactly as they do currently (the cookie is not used in filtering matches, only in replacing the value in the case of a modify).

Note there is no need for switches to store the cookie_mask, as it is only used for non-packet filtering/matching.

• Add uint64_t cookie, and uint64_t cookie_mask fields to ofp_flow_stats_request and ofp_aggregate_stats_request structures. This will enable users to query the flow tables using arbitrary cookie bits.

Draft Specification Diff

OpenFlow v1.0 Spec Diff - Cookie Enhancements