[单选题]Traditional network layer packet forwarding relies on the information provided by network layer （） protocols, or static routing, to make an independent （）decision at each hop within the network. The forwarding （）is based solely on the destination （本题）IP address. All packets for the same destination follow the same path across the network if no other equal-cost paths exist. Whenever a router has two equal-cost （）toward a destination, the packets toward the destination might take one or both of them, resulting in some degree of load sharing.
A.paths
B.distance
C.speed
D.session

[单选题]Traditional network layer packet forwarding relies on the information provided by network layer （） protocols, or static routing, to make an independent （本题）decision at each hop within the network. The forwarding （）is based solely on the destination （）IP address. All packets for the same destination follow the same path across the network if no other equal-cost paths exist. Whenever a router has two equal-cost （）toward a destination, the packets toward the destination might take one or both of them, resulting in some degree of load sharing.
A.switch
B.hop
C.host
D.cunstomer

[单选题]Traditional IP packet forwarding analyzes the（ ）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（请作答此空）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（ ）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 is（ ）.New techniques are therefore required to address and expand the functionality of an IP-based network infrastructure.This first chapter concentrates on identifying these restrictions and presents a new archiecture，known as multiprotocol（ ）switching，that provides solutions some of these restrictions.
A.routing
B.forwarding
C.transmission
D.management

[单选题]Together with the network layer,the transport layer is the heart of the protocol ( ).The network layer provides end-to-end () delivery using datagrams or virtual circuits.The transport layer builds on the network layer to provide data transport from a process on a () machine to a process on a destination machine with a desired level of reliability that is independent of the physical () currently in use.It provides the abstractions that applications nedd to use the network..Without the (请作答此空) layer,the whole concept of layered protocols would make little sense.
A.network
B.transport
C.link
D.physical