03-26-2025, 06:05 AM
Reference: https://www.oreilly.com/library/view/mpls-configuration-on/1587051990/1587051990_ch01lev1sec6.html
Special Outgoing Label Types
LSRs perform the operation of label swapping, imposition, or disposition depending on their location in the MPLS domain. In certain cases, the incoming label maps to special outgoing labels that define the operation to be performed at the upstream LSR or router. These labels are propagated by the downstream LSR during label distribution to the upstream LSR. The following outlines the types of outgoing labels that can be associated with a packet:
Special Outgoing Label Types
LSRs perform the operation of label swapping, imposition, or disposition depending on their location in the MPLS domain. In certain cases, the incoming label maps to special outgoing labels that define the operation to be performed at the upstream LSR or router. These labels are propagated by the downstream LSR during label distribution to the upstream LSR. The following outlines the types of outgoing labels that can be associated with a packet:
- Untagged— The incoming MPLS packet is converted to an IP packet and forwarded to the destination (MPLS to IP Domain transition). This is used in the implementation of MPLS VPN (discussed in Chapter 3).
- Implicit-null or POP label— This label is assigned when the top label of ...