CPC H04L 41/12 (2013.01) [H04L 45/02 (2013.01)] | 20 Claims |
1. A method for determining a port orientation, the method comprising:
receiving, by a first network device through a first port, a protocol data unit (PDU) sent by a second network device, wherein the PDU carries a topology level of the second network device in a network; and
determining, by the first network device based on the PDU, that the first port is an upstream port or a downstream port.
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