A packet processing apparatus (100, 700, 900), comprising: a packet identifying unit (102, 702, 902), for receiving a plurality of packets (P_IN) and checking identification information derived from the received packets to identify first packets (P_1) from the received packets (P_IN); and a packet modifying unit (104, 704, 904), coupled to the packet identifying unit (102, 702, 902), for checking payloads of the first packets (P_1) that are identified and selected from the received packets (P_IN) to identify second packets (P_2) from the first packets (P_1), where each of the second packets (P_2) has specific data included in a payload thereof, and for modifying at least the payload of each of the second packets (P_2) that are identified and selected from the first packets (P_1); wherein the specific data include data of at least one specific descriptor of a specific table section; wherein the packet modifying unit modifies each of the second packets (P_2) by dropping or masking the data of the at least one specific descriptor; wherein the payloads of the first packets (P_1) contain an original error-checking code of the specific table section, and the packet processing apparatus (100, 700, 900) further comprises an error-checking code processing unit, for performing an error check upon the specific table section according to the original error-checking code; and wherein, when an error checking result of performing the error check upon the specific table section indicates that the specific table section passes the error check, the error-checking code processing unit generates an updated error-checking code for a modified specific table section corresponding to the specific table section, and the packet modifying unit (104, 704, 904) replaces the original error-checking code transmitted via at least one first packet (P_1) corresponding to the specific table section with the updated error-checking code; characterized in that, when an error checking result of performing the error check upon the specific table section indicates that the specific table section fails to pass the error check, the packet modifying unit (104, 704, 904) keeps the original error checking code unchanged. a packet identifying unit (102, 702, 902), for receiving a plurality of packets (P_IN) and checking identification information derived from the received packets to identify first packets (P_1) from the received packets (P_IN); and a packet modifying unit (104, 704, 904), coupled to the packet identifying unit (102, 702, 902), for checking payloads of the first packets (P_1) that are identified and selected from the received packets (P_IN) to identify second packets (P_2) from the first packets (P_1), where each of the second packets (P_2) has specific data included in a payload thereof, and for modifying at least the payload of each of the second packets (P_2) that are identified and selected from the first packets (P_1); wherein the specific data include data of at least one specific descriptor of a specific table section; wherein the packet modifying unit modifies each of the second packets (P_2) by dropping or masking the data of the at least one specific descriptor; wherein the payloads of the first packets (P_1) contain an original error-checking code of the specific table section, and the packet processing apparatus (100, 700, 900) further comprises an error-checking code processing unit, for performing an error check upon the specific table section according to the original error-checking code; and wherein, when an error checking result of performing the error check upon the specific table section indicates that the specific table section passes the error check, the error-checking code processing unit generates an updated error-checking code for a modified specific table section corresponding to the specific table section, and the packet modifying unit (104, 704, 904) replaces the original error-checking code transmitted via at least one first packet (P_1) corresponding to the specific table section with the updated error-checking code; characterized in that, when an error checking result of performing the error check upon the specific table section indicates that the specific table section fails to pass the error check, the packet modifying unit (104, 704, 904) keeps the original error checking code unchanged.