U.S.Patent Dec.8,2020 Sheet 3 of 9 US10,862,817B2 First device Routing device Second device S101.A first device sends a first data packet to a routing device S102.The routing device receives the first data packet S103.The routing device determines that an average queue length of a data packet queue is greater than or equal to a first preset threshold and is less than or equal to a second preset threshold 工 S104.The routing device makes a congestion mark for the first data packet,and adds the first data packet to the data packet queue S105.The routing device sends the first data packet to a second device S106.The second device receives the first data packet S107.The second device makes an ECE mark for a first acknowledgement packet S108.The second device sends the first acknowledgement packet to the first device S109.The first device receives the first acknowledgement packet S110.The first device determines a first sub stream set S111.The first device performs congestion control on sub streams in the first sub stream set FIG.4U.S. Patent Dec. 8 , 2 2020 Sheet 3 of 9 US 10,862,817 B2 First device Routing device Second device S101 . A first device sends a first data packet to a routing device S102 . The routing device receives the first data packet S103 . The routing device determines that an average queue length of a data packet queue is greater than or equal to a first preset threshold and is less than or equal to a second preset threshold S104 . The routing device makes a congestion mark for the first data packet , and adds the first data packet to the data packet queue $ 105 . The routing device sends the first data packet to a second device S106 . The second device receives the first data packet S107 . The second device makes an ECE mark for a first acknowledgement packet S108 . The second device sends the first acknowledgement packet to the first device S109 . The first device receives the first acknowledgement packet S110 . The first device determines a first sub stream set S111 . The first device performs congestion control on sub streams in the first sub stream set FIG . 4