+ <dt><code>gre64</code></dt>
+ <dd>
+ It is same as GRE, but it allows 64 bit key. To store higher 32-bits
+ of key, it uses GRE protocol sequence number field. This is non
+ standard use of GRE protocol since OVS does not increment
+ sequence number for every packet at time of encap as expected by
+ standard GRE implementation. See <ref group="Tunnel Options"/>
+ for information on configuring GRE tunnels.
+ </dd>
+
+ <dt><code>ipsec_gre64</code></dt>
+ <dd>
+ Same as IPSEC_GRE except 64 bit key.
+ </dd>
+