Duplicated packets. These occur when the routing algorithm gets into a loop or when congestion causes a long delay. The sending host retransmits. If a new route is taken, the next packet may arrive before the original, and the extra packet will be forgotten. If the delayed packet shows up at the receiver after the sequence numbers have wrapped around, it will be accepted, and the correct packet rejected as a duplicate. The user will receive incorrect data from the transport station, and no error will be detected.; 重復的報文分組,當路徑算法進入循環(huán)或因阻塞引起長時間延遲時出現(xiàn)的情況,發(fā)送主機 將重發(fā)報文分組。如果選擇了新的路徑,則后面一個報文分組可能在原來一個之前到達,且此 多余的報文分組會被忽略。如果因序列號折轉(zhuǎn)而在接收端出現(xiàn)延遲報文分組時,則它將被接 收,而正確的報文分組作為重復報文而被拒絕,用戶將從傳輸站收到不正確的數(shù)據(jù),而且錯誤 檢測不出來。