Either -1 or the VCI of the connection on which F5 OAM
loopback cells are to be sent.
If the value of this object is -1, then an F4 OAM loopback
cells will be sent on the VPC indicated by oamLoopbackPingVpi.
An instance of this object cannot be created until the
associated instance of oamLoopbackPingVpi is created.
Once an instance of this object is created, its
value can not be changed.