``packet_in'' message will be sent only to the controllers having
controller id zero which have registered for the invalid ttl packets.
.
+.IP \fBdec_mpls_ttl\fR
+Decrement TTL of the outer MPLS label stack entry of a packet. If the TTL
+is initially zero, no decrement occurs. Instead, a ``packet-in'' message
+with reason code \fBOFPR_INVALID_TTL\fR is sent to each connected
+controller with controller id zer that has enabled receiving them.
+Processing the current set of actions then stops. However, if the current
+set of actions was reached through ``resubmit'' then remaining actions in
+outer levels resume processing.
+.
.IP \fBnote:\fR[\fIhh\fR]...
Does nothing at all. Any number of bytes represented as hex digits
\fIhh\fR may be included. Pairs of hex digits may be separated by