d it to R5 after popping label 16005. R5 will see 24056, which is the adjacency segment R5-R6 and it will pop the label and send the packet to R6 using R5-R6 link. In this entire process, only the source router will need to construct the label stack that determines the explicit path (which can be done using SDN controller) and the rest of the routers follows the label swapping/pop operations. There is no state information about the path in intermediate routers R4, R5, and R6. 13.2.3.3 Faster Restoration Using Segment Routing The ability to push additional labels (segments) at any intermediate node provides the capability to do fast restoration without RSVP/TE. This is illustrated in the following example. For protecting R2-R3 link failure, router R2 will precompute paths to the various destinations that use R2-R3 in their path. In the left side of Figure 13.19, R2 determines that packets to destina- tion R6 can be restored by sending the traffic first to R5 and then using link R5-R6. When R2-R3 link fails, R2 will detect the failure, push label 24056 (16005 is not necessary as R2 is adjacent to R5) and forward the packet to R5. R5 will recognize label 24056 is its adjacency segment and it will pop it and send the packet on R5-R6 link. Thus, the traffic can be restored under 50 ms. Once the network recognizes via the core routing protocol that R2-R3 link has failed, router R1 will find alternate path via R4 and forward the traffic to R4 directly and the packets from R1 to R6 no longer use the longer R1-R2-R5-R6 path (FRR path). Note-the backup path state is NOT present in any other router except router R2. 13.2.3.4 Segment Routing Benefits In addition to removing LDP for label distribution and supporting FRR (without the need to con- figure TE tunnels), segment routing has other use cases such as service chaining (using service segments), controlling egress peering by the source rather than egress border nodes, and class of service-based routing. 13.2.3.5 Segment Routing versus RSVP-TE TE using segment routing wou