<row><entry><varname>xfrm</varname></entry>
<entry>A virtual tunnel interface like vti/vti6 but with several advantages.</entry></row>
+ <row><entry><varname>ifb</varname></entry>
+ <entry> The Intermediate Functional Block (ifb) pseudo network interface acts as a QoS concentrator for multiple different sources of traffic.</entry></row>
+
</tbody>
</tgroup>
</table>