The protection architecture type of the protection domain. This object represents both the bridge type, which can be either a permanent bridge (1+1) or a selector bridge (1:1); and the switching scheme, which can be either unidirectional or bidirectional. 1+1 In the 1+1 protection scheme, a fully dedicated protection path is allocated. Data traffic is copied and fed at the source to both the working path and the protection path. The traffic on the working path and protection path is transmitted simultaneously to the sink of the protection domain, where selection between the working path and the protection path is performed. 1:1 In the 1:1 protection scheme, a protection path is allocated to protect against a defect, failure, or degradation on the working path. In normal conditions, data traffic is transmitted over the working path, while the protection path functions in the idle state. If there is a defect on the working path or a specific administrative request, traffic is switched to the protection path. bidirectional In the bidirectional protection scheme, both directions will be switched simultaneously even if the fault applies to only one direction of the path. unidirectional In the unidirectional protection scheme, protection switching will be performed independently for each direction of a bidirectional transport path. This object may not be modified if the associated mplsLpsConfigRowStatus object is equal to active(1).