X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Fovs.git;a=blobdiff_plain;f=FAQ.md;h=8bd7ab9190332934b24f015f39db2c811522b813;hp=9280065c5dce72c0fa09f3cde7643a2328dce7bd;hb=HEAD;hpb=10d8e9c6719530a317dfe657442b10023f2aec5d

diff --git a/FAQ.md b/FAQ.md
index 9280065c5..8bd7ab919 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -156,7 +156,7 @@ A: The following table lists the Linux kernel versions against which the
 |    2.1.x     | 2.6.32 to 3.11
 |    2.3.x     | 2.6.32 to 3.14
 |    2.4.x     | 2.6.32 to 4.0
-|    2.5.x     | 2.6.32 to 4.2
+|    2.5.x     | 2.6.32 to 4.3
 
    Open vSwitch userspace should also work with the Linux kernel module
    built into Linux 3.3 and later.
@@ -165,6 +165,73 @@ A: The following table lists the Linux kernel versions against which the
    It should build against almost any kernel, certainly against 2.6.32
    and later.
 
+### Q: Are all features available with all datapaths?
+
+A: Open vSwitch supports different datapaths on different platforms.  Each
+   datapath has a different feature set: the following tables try to summarize
+   the status.
+
+   Supported datapaths:
+
+   * *Linux upstream*: The datapath implemented by the kernel module shipped
+                       with Linux upstream.  Since features have been gradually
+                       introduced into the kernel, the table mentions the first
+                       Linux release whose OVS module supports the feature.
+
+   * *Linux OVS tree*: The datapath implemented by the Linux kernel module
+                       distributed with the OVS source tree. Some features of
+                       this module rely on functionality not available in older
+                       kernels: in this case the minumum Linux version (against
+                       which the feature can be compiled) is listed.
+
+   * *Userspace*: Also known as DPDK, dpif-netdev or dummy datapath. It is the
+                  only datapath that works on NetBSD and FreeBSD.
+
+   * *Hyper-V*: Also known as the Windows datapath.
+
+   The following table lists the datapath supported features from
+   an Open vSwitch user's perspective.
+
+Feature               | Linux upstream | Linux OVS tree | Userspace | Hyper-V |
+----------------------|:--------------:|:--------------:|:---------:|:-------:|
+Connection tracking   |      4.3       |       3.10     |    NO     |   NO    |
+Tunnel - LISP         |      NO        |       YES      |    NO     |   NO    |
+Tunnel - STT          |      NO        |       3.5      |    NO     |   YES   |
+Tunnel - GRE          |      3.11      |       YES      |    YES    |   YES   |
+Tunnel - VXLAN        |      3.12      |       YES      |    YES    |   YES   |
+Tunnel - Geneve       |      3.18      |       YES      |    YES    |   NO    |
+QoS - Policing        |      YES       |       YES      |    NO     |   NO    |
+QoS - Shaping         |      YES       |       YES      |    NO     |   NO    |
+sFlow                 |      YES       |       YES      |    YES    |   NO    |
+Set action            |      YES       |       YES      |    YES    | PARTIAL |
+NIC Bonding           |      YES       |       YES      |    YES    |   NO    |
+Multiple VTEPs        |      YES       |       YES      |    YES    |   NO    |
+
+   **Notes:**
+   * Only a limited set of flow fields is modifiable via the set action by the
+     Hyper-V datapath.
+   * The Hyper-V datapath only supports one physical NIC per datapath. This is
+     why bonding is not supported.
+   * The Hyper-V datapath can have at most one IP address configured as a
+     tunnel endpoint.
+
+   The following table lists features that do not *directly* impact an
+   Open vSwitch user, e.g. because their absence can be hidden by the ofproto
+   layer (usually this comes with a performance penalty).
+
+Feature               | Linux upstream | Linux OVS tree | Userspace | Hyper-V |
+----------------------|:--------------:|:--------------:|:---------:|:-------:|
+SCTP flows            |      3.12      |       YES      |    YES    |   YES   |
+MPLS                  |      3.19      |       YES      |    YES    |   YES   |
+UFID                  |      4.0       |       YES      |    YES    |   NO    |
+Megaflows             |      3.12      |       YES      |    YES    |   NO    |
+Masked set action     |      4.0       |       YES      |    YES    |   NO    |
+Recirculation         |      3.19      |       YES      |    YES    |   NO    |
+TCP flags matching    |      3.13      |       YES      |    YES    |   NO    |
+Validate flow actions |      YES       |       YES      |    N/A    |   NO    |
+Multiple datapaths    |      YES       |       YES      |    YES    |   NO    |
+Tunnel TSO - STT      |      N/A       |       YES      |    NO     |   YES   |
+
 ### Q: I get an error like this when I configure Open vSwitch:
 
        configure: error: Linux kernel in <dir> is version <x>, but
@@ -1912,6 +1979,25 @@ A: When a switch sends a packet to an OpenFlow controller using a
    buffering that the OpenFlow specification requires implementations
    to document.
 
+### Q: How does OVS divide flows among buckets in an OpenFlow "select" group?
+
+A: In Open vSwitch 2.3 and earlier, Open vSwitch used the destination
+   Ethernet address to choose a bucket in a select group.
+
+   Open vSwitch 2.4 and later by default hashes the source and
+   destination Ethernet address, VLAN ID, Ethernet type, IPv4/v6
+   source and destination address and protocol, and for TCP and SCTP
+   only, the source and destination ports.  The hash is "symmetric",
+   meaning that exchanging source and destination addresses does not
+   change the bucket selection.
+
+   Select groups in Open vSwitch 2.4 and later can be configured to
+   use a different hash function, using a Netronome extension to the
+   OpenFlow 1.5+ group_mod message.  For more information, see
+   Documentation/group-selection-method-property.txt in the Open
+   vSwitch source tree.  (OpenFlow 1.5 support in Open vSwitch is still
+   experimental.)
+
 
 Development
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