【導(dǎo)讀】國(guó)內(nèi)外NGN發(fā)展及現(xiàn)狀···································4. 第二章NGN的關(guān)鍵技術(shù)及比較···································4. 軟交換設(shè)計(jì)原理········································5. 軟交換的下一代網(wǎng)絡(luò)系統(tǒng)結(jié)構(gòu)····························5. 基于IMS的下一代網(wǎng)絡(luò)·····································6