US Patent 10027587 Non-recirculating label switching packet processing

Disclosed herein is an apparatus for processing an Internet Protocol (IP) header and label switching (LS) headers of a packet in a pipeline. The apparatus includes an LS header processing circuit configured to select a first operation for the packet using an LS header from the packet, and an IP header processing circuit configured to perform an IP lookup to select a second operation for the packet. The apparatus further includes a tunnel initiation circuit configured to initiate an LS tunnel or IP tunnel. The LS header processing circuit, the IP header processing circuit, and the tunnel initiation circuit are operable to operate sequentially on a same packet and concurrently on different packets in a pipeline. Each of these circuits is operable to be bypassed based on an outermost header in the packet, or the selected one of the first operation or the second operation.