（)是在专家个人判断和专家会议法的基础上发展起来的一种专家调查法。A．德尔菲法B．头脑风暴法C．交

从供选择的答案中，选出最确切的解答。

Networks can be interconnected by different devices. In the physical layer, networks can be connected by(1)or hubs, which just move the bits from one network to an identical network. One layer up we fine bridges and switches, which operate at data link layer. They can accept(2)，examine the MAC address and forward the frames to a different network while doing minor protocol translation in the process. In the network layer, we have routers that can connect two networks. If two networks have(3)network layer, the router may be able to translate between the packer formats. In the transport layer we find transport gateway, which can interface between two transport connections. Finally, in the application layer, application gateways translate message(4). As an example, gateways between Intemet E-mail and X.400 E-mail must(5)the E-mail message and change various header fields.

e connected by(66)or hubs, which just move the bits from one network to an identical network. One layer up we find bridges and switches, which operate at data link layer. They can accept(67), examine the MAC address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer, we have routers that can connect two networks. If two networks have(68)network layer, the router may be able to translate between the packet formats. In the transport layer we fmd transport gateway, which can interface between two transport connections. Finally, in the application layer, application gateways translate message(69). As an example, gateways between Internet e-mail and X.400 e-mail must(70)the e-mail message and change various header fields.

A．repeaters

B．relays

C．connectors

D．modems

e connected by(66)or hubs, which just move the bits from one network to an identical network. One layer up we find bridges and switches, which operate at data link layer. They can accept(67), examine the MAC address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer, we have routers that can connect two networks. If two networks have(68)network layer, the router may be able to translate between the packet formats. In the transport layer we fmd transport gateway, which can interface between two transport connections. Finally, in the application layer, application gateways translate message(69). As an example, gateways between Internet e-mail and X.400 e-mail must(70)the e-mail message and change various header fields.

A．repeaters

B．relays

C．connectors

D．modems

connected by(1)or hubs. Which just move the bits from one network to an identical network. One layer up we find bridges and switches which operate at data link layer. They can accept(2)examine the MAC address and forward the frames to a different network while doing minor protocol translation in the process in me network layer, we have routers that can connect two networks, If two networks have(3)network layer, the router may be able to translate between the packer formats. In the transport layer we find transport gateway, which can interface between two transport connections Finally, in the application layer, application gateways translate message(4). As an example, gateways between Internet e-mail and X.400 e-mail must(5)the e-mail message and change various header fields.

A．reapers

B．relays

C．packages

D．modems

connected by (71) or hubs．which just move the bits from one network to an identical network．One layer up we find bridges and switches which operate at data link layer．They can accept (72) ，examine the MAC address and forward the frames to a different network while doing minor protocol translation in the process in me network layer，we have routers that can connect two networks，If two networks have (73) network layer，the router may be able to translate betweenthe packer formats．In the transport layer we find transport gateway，which can interface between two transport connections Finally，in the application layer，application gateways translate message (74) ．As an example，gateways between Internet e-mail and X，400 e-mail must (75) thee-mail message and change various header fields．

(68)

A．reapers

B．relays

C．packages

D．modems

e connected by(1)or hubs, which just move the bits from one network to an identical network. One layer up we find bridges and switches, which operate at data link layer. They can accept(2), examine the MAC address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer, we have routers that can connect two networks. If two networks have(3)network layer, the router may be able to translate between the packet formats. In the transport layer we find transport gateway, which can interface between two transport connections. Finally, in the application layer, application gateways translate message(4). As an example, gateways between Internet e-mail and X.400 e-mail must(5)the e-mail message and change various header fields.

A．reapers

B．relays

C．connectors

D．modems

connected by(66)or Hubs, which just move the bits from one network to an identical net-work. One layer up we find bridgas and swiehes, which operate at data link layer. They can accept(67), examine the MAC address, and forward the frames to a different network while doing minor protocol translation in the process. In the network layer, we have routers that can connect two netwoks. If two networks have(68)network layer, the router may be able to translate between the packet formats. In the transport layer we find transport gateway, which can interface between the two transport connections. Finally, in the application layer, application gateways translate message(69). As an example, gateways between Internet e-mail and X.400 e-mail must(70) the e-mail message and change various header fields.

A．reapers

B．relays

C．connects

D．modems

We can learn from Paragraph 3 that______.

A．information discovery and information integration are requirements of different organizations

B．organizations need to shift between a centralized structure and a richly connected network

C．a richly connected network works better than a centralized structure

D．centralized structures work against densely interconnected networks

● (74) functions with two layers of protocols．It can connect networks of different speeds and can be adapted to an environment as it expands．

(74) A．The hub

B．The bridge

C．The router

D．The proxy

The Internet is a () system of interconnected computer networks that use the standard Internet protocol suits(TCP/IP) to serve several billion users worldwide。

A．global B．regional C．local D．national