In a Segment Routing (SR) technology, a control plane uses an Interior Gateway Protocol (IGP) based on a link state, such as the Intermediate System to Intermediate System (IS-IS) protocol or the Open Shortest Path First (OSPF) protocol to transfer a Multiprotocol Label Switching (MPLS) Tunnel Label (TL) that is of a Label Switching Router (LSR) and has global significance, and a data plane forwards an MPLS packet based on the TL that is sent by the control plane and has global significance. Compared with an existing MPLS technology system, the segment routing technology simplifies operation, maintenance, and management of an MPLS network, and an existing label advertisement protocol such as the Label Distribution Protocol (LDP), the Resource Reservation Protocol-Traffic Engineering (RSVP-TE), or the Border Gateway Protocol (BGP) is not required in an SR network.
An Entropy Label (EL) technology is a method for implementing a load balancing capability of an MPLS network, and a basic idea is as follows: An ingress (Ingress) LSR of an MPLS tunnel inserts an Entropy Label Indicator (ELI) and an entropy label (Entropy Label) into an MPLS label stack (Label Stack), where the ELI is a reserved label, and a value of the label is 7, indicating that an MPLS label following the ELI is an EL. In this case, when an MPLS packet that carries the foregoing ELI and EL passes through a transit (Transit) LSR, the Transit LSR can obtain the EL, perform hash (Hash) processing on the EL, and perform load balancing processing on the MPLS packet based on a Hash result. In an SR network, the Ingress LSR of the MPLS tunnel cannot determine whether an egress (Egress) LSR of the MPLS tunnel has Entropy Label Capability (ELC); therefore, the SR network does not support the EL technology and the Transit LSR cannot use the EL technology to implement load balancing for forwarding of the MPLS packet.
USPTO Backgrounds
USPTO Backgrounds