进行膳食调查的主要目的是（）

A.是营养不足或缺乏的检查

B.了解膳食组成及营养素摄取情况

C.了解有无膳食缺乏症

D.了解机体营养情况

E.了解体内的营养素水平

Traditional IP packet forwarding analyzes the____(1)____IP address contained in the network layer header of each packet as the packet travels from its source to its final destination．A router analyzes the destination IP address independently at each hop in the network．Dynamic ____(2)____protocols or static configuration builds the database needed to analyze the destination IP address(the routing table)．The process of implementing traditional IP routing also is called hop—by—hop destination—based____(3)____routing．Although successful，and obviously widely deployed，certain restrictions，which have been realized for some time，exist for this method of packet forwarding that diminish its____(4)____．New techniques are therefore required to address and expand the functionality of an IP—based network infrastructure．This first chapter concentrate on identifying these restrictions and presents a rew，architecture，known as multipIeprotocol____(5)____switching，that provides solutions to some of these restrictions．

(2)

A．routing

B．forwarding

C．transmission

D．management