PECP segment routing path segment tag binding extension

The invention discloses a method for supporting establishment of a segment routing traffic engineering label switched path (SR-TE LSP for short), and the method does not need to consider the limitation of a forwarding node on the maximum segment depth (MSD for short). According to the method, a path calculation element (PCE for short) obtains the SRID (namely a label) from all path calculation clients (PCC for short) because the PCC runs an internal gateway protocol (IGP), and the internal gateway protocol (IGP) is consistent with a traffic engineering database (TEDB) for short. The traditional technology is only limited to using PCE for label distribution. They do not guide or suggest label allocation using PCC. The present invention associates an ingress tag with an egress tag stack and a tag range for a PCE for a sub-LSP, i.e. Part of the LSP. The PCE can generate a tag binding from a defined tag range (i.e., tag type 3) and send the tag binding to a network device. 本说明书公开了一种支持分段路由流量工程标签交换路径(Segment Routin