In general, the invention provides for the relaying of ATM cells through an IP network. In one embodiment, an apparatus, such as a routing device, comprises a first interface card for coupling to an asynchronous transfer mode (ATM) network, and a second interface card for coupling to an Internet Protocol (IP) network. The apparatus further comprises a control unit to assign labels to inbound cells from the ATM network to form outbound Multiprotocol Label Switching (MPLS) packets for forwarding to the IP network, and to remove labels from inbound MPLS packets from the IP network to form outbound cells for forwarding to the ATM network. The apparatus can encapsulate the ATM cells within MPLS packets, and route the MPLS packets through the IP network without regard to the content of the ATM cells. In this manner, the routers may relay ATM cells of any type, including data and control cells.