This object specifies the signaling protocol
used to obtain the ingress and egress labels
used in frames transmitted and received on
this SDP. When the value of this object is
'none' then the labels are manually assigned
at the time the SDP is bound to a service. The
value of this object can only be changed while
the admin status of the SDP is 'down'.
An 'inconsistentValue' error is returned if this object
is not set to 'none' when sdpDelivery is set to 'mpls'.
Default value of this object is set to 'none' when
sdpDelivery is set to 'mpls' otherwise default value
for this object is set to 'tldp'.