datapath/ vport ---
vswitchd/ iface port
ofproto/ port bundle
- lib/bond.c slave bond
+ ofproto/bond.c slave bond
lib/lacp.c slave lacp
lib/netdev.c netdev ---
database Interface Port
* A dpif provider is usually easier to implement, but most
appropriate for software switching. It "explodes" wildcard
- rules into exact-match entries. This allows fast hash lookups
- in software, but makes inefficient use of TCAMs in hardware
- that support wildcarding.
+ rules into exact-match entries (with an optional wildcard mask).
+ This allows fast hash lookups in software, but makes
+ inefficient use of TCAMs in hardware that support wildcarding.
The following sections describe how to implement each kind of port.
Open vSwitch has a built-in ofproto provider named "ofproto-dpif",
which is built on top of a library for manipulating datapaths, called
-"dpif". A "datapath" is a simple flow table, one that supports only
-exact-match flows, that is, flows without wildcards. When a packet
-arrives on a network device, the datapath looks for it in this
-exact-match table. If there is a match, then it performs the
-associated actions. If there is no match, the datapath passes the
-packet up to ofproto-dpif, which maintains an OpenFlow flow table
-(that supports wildcards). If the packet matches in this flow table,
-then ofproto-dpif executes its actions and inserts a new exact-match
-entry into the dpif flow table. (Otherwise, ofproto-dpif passes the
+"dpif". A "datapath" is a simple flow table, one that is only required
+to support exact-match flows, that is, flows without wildcards. When a
+packet arrives on a network device, the datapath looks for it in this
+table. If there is a match, then it performs the associated actions.
+If there is no match, the datapath passes the packet up to ofproto-dpif,
+which maintains the full OpenFlow flow table. If the packet matches in
+this flow table, then ofproto-dpif executes its actions and inserts a
+new entry into the dpif flow table. (Otherwise, ofproto-dpif passes the
packet up to ofproto to send the packet to the OpenFlow controller, if
one is configured.)
+When calculating the dpif flow, ofproto-dpif generates an exact-match
+flow that describes the missed packet. It makes an effort to figure out
+what fields can be wildcarded based on the switch's configuration and
+OpenFlow flow table. The dpif is free to ignore the suggested wildcards
+and only support the exact-match entry. However, if the dpif supports
+wildcarding, then it can use the masks to match multiple flows with
+fewer entries and potentially significantly reduce the number of flow
+misses handled by ofproto-dpif.
+
The "dpif" library in turn delegates much of its functionality to a
"dpif provider". The following diagram shows how dpif providers fit
into the Open vSwitch architecture:
git://git.onelab.eu / sliver-openvswitch.git / blobdiff