either be a 32-bit number or the word <code>flow</code>. If
<code>flow</code> is specified then the key may be set using
the <code>set_tunnel</code> Nicira OpenFlow vendor extension (0
- is used in the absense of an action). The ovs-ofctl manual
+ is used in the absence of an action). The ovs-ofctl manual
page contains additional information about the Nicira OpenFlow
vendor extensions. Default is no key.</dd>
</dl>