In SNA, a field in a FID4 transmission header that contains an element address, which combined with the subarea address in the origin subarea field (OSAF), gives the complete network address of the originating network addressable unit (NAU).; 在系統(tǒng)網(wǎng)絡(luò)體系結(jié)構(gòu)(SNA)中,格式標識符4(FID4)中傳送報頭的字段,它包含一個單元地址, 該地址與初始分區(qū)字段(OSAE)中的分區(qū)地址組合,給出發(fā)端網(wǎng)絡(luò)可尋址單元(NAU)的完整網(wǎng) 絡(luò)地址。對照 destination element field (DEF)。參閱format identification (FID) field。