Methods, systems, and computer program products are provided for inserting the packet into a tail of a linked list buffer, and the linked list buffer includes a plurality of Buffer Descriptors (BD), a HEAD pointer pointing to a null Buffer Descriptor (NullBD) and a NULLBD pointer. The NULLBD pointer is switched to point to the NullBD and the HEAD pointer to point to a valid BD which represents a memory address of payload data in the packet to be transmitted. Upon transmission of the packet, the HEAD pointer is converted to point to the NullBD and the NULLBD pointer to point to the valid BD. The valid BD pointed by the NULLBD pointer is finally transferred to a free linked list buffer so that the NULLBD pointer points to no memory address.