MPLS Configuration on Cisco IOS Software

Cell-Mode MPLS

When using ATM connectivity between devices, MPLS applies to cells, not frames. Cells are used to transport data plane information. When ATM labels are used in an MPLS core, the operating mode of MPLS is called cell-mode MPLS. As previously mentioned, peering between LSRs via routed ATM PVCs can also be implemented but is considered a frame-mode implementation.

In cell-mode MPLS, the LSRs in the core of the MPLS network are ATM switches that forward data based on the ATM header. If the ATM LSR functions as a pure ATM switch (data plane), an external control plane component also called the label switch controller (LSC) is required for propagation of control plane information. In some cases, however, the ATM LSR is capable of propagating ...