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:
Figure 1-12 illustrates the usage of these label types.
Figure 1-12. Special Label Types
MPLS Overview
Basic MPLS Configuration
Basic MPLS VPN Overview and Configuration
PE-CE Routing Protocol-Static and RIP
PE-CE Routing Protocol-OSPF and EIGRP
Implementing BGP in MPLS VPNs
Inter-Provider VPNs
Carrier Supporting Carriers
MPLS Traffic Engineering
Implementing VPNs with Layer 2 Tunneling Protocol Version 3
Any Transport over MPLS (AToM)
Virtual Private LAN Service (VPLS)
Implementing Quality of Service in MPLS Networks
MPLS Features and Case Studies