SAR_TBD_EPDU
tbd->word_1 = SAR_TBD_OAM | ATM_CELL_PAYLOAD | SAR_TBD_EPDU;
tbd->word_1 = SAR_TBD_EPDU | SAR_TBD_AAL0 |
tbd->word_1 = SAR_TBD_EPDU | SAR_TBD_AAL34 |
tbd->word_1 = SAR_TBD_EPDU | SAR_TBD_AAL5 | skb->len;