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Diffstat (limited to 'DESIGN')
| -rw-r--r-- | DESIGN | 85 |
1 files changed, 85 insertions, 0 deletions
@@ -20,6 +20,91 @@ to 'internal' ports whose port numbers are less than OFPP_MAX, we interpret OFPP_LOCAL as a physical port and support OFPAT_ENQUEUE on it as well. +Flow Cookies +============ + +OpenFlow 1.0 and later versions have the concept of a "flow cookie", +which is a 64-bit integer value attached to each flow. The treatment +of the flow cookie has varied greatly across OpenFlow versions, +however. + +In OpenFlow 1.0: + + - OFPFC_ADD set the cookie in the flow that it added. + + - OFPFC_MODIFY and OFPFC_MODIFY_STRICT updated the cookie for + the flow or flows that it modified. + + - OFPST_FLOW messages included the flow cookie. + + - OFPT_FLOW_REMOVED messages reported the cookie of the flow + that was removed. + +OpenFlow 1.1 made the following changes: + + - Flow mod operations OFPFC_MODIFY, OFPFC_MODIFY_STRICT, + OFPFC_DELETE, and OFPFC_DELETE_STRICT, plus flow stats + requests and aggregate stats requests, gained the ability to + match on flow cookies with an arbitrary mask. + + - OFPFC_MODIFY and OFPFC_MODIFY_STRICT were changed to add a + new flow, in the case of no match, only if the flow table + modification operation did not match on the cookie field. + (In OpenFlow 1.0, modify operations always added a new flow + when there was no match.) + + - OFPFC_MODIFY and OFPFC_MODIFY_STRICT no longer updated flow + cookies. + +OpenFlow 1.2 made the following changes: + + - OFPC_MODIFY and OFPFC_MODIFY_STRICT were changed to never + add a new flow, regardless of whether the flow cookie was + used for matching. + +Open vSwitch support for OpenFlow 1.0 implements the OpenFlow 1.0 +behavior with the following extensions: + + - An NXM extension field NXM_NX_COOKIE(_W) allows the NXM + versions of OFPFC_MODIFY, OFPFC_MODIFY_STRICT, OFPFC_DELETE, + and OFPFC_DELETE_STRICT flow_mods, plus flow stats requests + and aggregate stats requests, to match on flow cookies with + arbitrary masks. This is much like the equivalent OpenFlow + 1.1 feature. + + - Like OpenFlow 1.1, OFPC_MODIFY and OFPFC_MODIFY_STRICT add a + new flow if there is no match and the mask is zero (or not + given). + + - The "cookie" field in OFPT_FLOW_MOD and NXT_FLOW_MOD messages + is used as the cookie value for OFPFC_ADD commands, as + described in OpenFlow 1.0. For OFPFC_MODIFY and + OFPFC_MODIFY_STRICT commands, the "cookie" field is used as a + new cookie for flows that match unless it is UINT64_MAX, in + which case the flow's cookie is not updated. + + - NXT_PACKET_IN (the Nicira extended version of + OFPT_PACKET_IN) reports the cookie of the rule that + generated the packet, or all-1-bits if no rule generated the + packet. (Older versions of OVS used all-0-bits instead of + all-1-bits.) + +The following table shows the handling of different protocols when +receiving OFPFC_MODIFY and OFPFC_MODIFY_STRICT messages. A mask of 0 +indicates either an explicit mask of zero or an implicit one by not +specifying the NXM_NX_COOKIE(_W) field. + + Match Update Add on miss Add on miss + cookie cookie mask!=0 mask==0 + ====== ====== =========== =========== +OpenFlow 1.0 no yes <always add on miss> +OpenFlow 1.1 yes no no yes +OpenFlow 1.2 yes no no no +NXM yes yes* no yes + +* Updates the flow's cookie unless the "cookie" field is UINT64_MAX. + + Multiple Table Support ====================== |