to establish the whole failed GLSP to the egress node once again. This is a working involving both layer 2 and layer 1. However, it is not guaranteed that the process will succeed because the bandwidth is not prereserved and could be unavailable (it will not be possible to establish a recov- ery path). Two resource reuse procedures are associated to this kind of restoration technique: stub reuse and stub release. The stub reuse procedure consists in the fact that the recovery path may use parts of the working path not affected by the failure. The stub release procedure consists in the possibility that resources related to faulty connections are freed to be used by different connections for their recovery. 2. End-to-end GLSP restoration with presignaled recovery bandwidth reservation and no label preselection (type 2 restoration): The bandwidth on the links that will constitute the recovery path is reserved by using signaling protocols, although the recovery path is not established. After a fail- ure, the labels are chosen and the path is established by using a signaling protocol and, if necessary, the OXCs are rearranged. Even new routing through layer 2 topol- ogy could happen to exploit LSR grooming capability. The reserved resources may be shared among different recovery paths, but only when they are not affected by the same failures. Telecommunication Networks 3. End-to-end GLSP restoration with presignaled recovery bandwidth reservation and label preselection (type 3 restoration): Analogous to the method described earlier only faster, since the labels are assigned before the failure. Therefore, the necessity of OXC switching is signaled immediately after the fault notification. These restoration methods can be applied at each layer of the network (but at layer 0 naturally), in this section we will consider them applied at layer 1 and we will compare their performances with those of the different protection mechanisms first under a qualitative point of view and then with a quantitative comparison. 8.5.2.1 Ban