软考中级
Networks can be interconnected by different devices. In the physical layer, networks can be 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 l
题目
Networks can be interconnected by different devices. In the physical layer, networks can be 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
参考答案和解析
解析：网络可以用不同的设备互连。在物理层，用中继器或集线器互连，这些设备只是在相同的网络之间传关比特串。在上面的数据链路层，可以使用网桥或交换机，这些设备接收数据帧，检查MAC地址，并可以实现少量的协议转换，把数据帧转发到不同的网络中。在网络层，我们使用路由器连接两个网络。如果两个网络的网络层不同，路由器能够对分组格式进行转换。在传输层，我们使用传输网关，它可以在两个传输连接之间建立接口。最后，在应用层，应用网关实现消息语法之间的翻译。例如，在Internet邮件和X.400邮件之间的网关可以对邮件报文进行语法分析，对报文的各个报头字段做出改变。
相似问题和答案
第1题：
In most WANs, the network contains numerous cables or telephone lines, each one connecting a pair of
A．hosts
B．routers
C．servers
D．networks
第2题：
You perform a security audit of a server named DC1. You install the Microsoft Network Monitor 3.0 application on DC1.You plan to capture all the LDAP traffic that comes to and goes from the server between 20:00 and 07:00 the next day and save it to the E:\data.cap file. You create a scheduled task. You add a new Start a program action to the task.You need to add the application name and the application arguments to the new action.What should you do?（）
A. Add nmcap.exe as the application name. Add the /networks * /capture LDAP /file e:\data.cap /stopwhen /timeafter 11hours line as arguments.
B. Add netmon.exe as the application name. Add the /networks */capture LDAP /file e:\data.cap /stopwhen /timeafter 11hours line as arguments.
C. Add nmcap.exe as the application name. Add the /networks * /capture !LDAP /file e:\data.cap /stopwhen /timeafter 11hours line as arguments.
D. Add nmconfig.exe as the application name. Add the /networks * /capture &LDAP /file e:\data.cap /stopwhen /timeafter 11hours line as arguments.
第3题：
文中（ 2 ）处正确的答案是（ ）。
A．/etc/networks/dhcpd
B．/usr/sbin/dhcp
C．/etc/networks/dhcp
D．/usr/sbin/dhcpd
第4题：
B.connection
C.lines
D.networks
第5题：
A.CAN 2.0A,CAN 2.0C
B.CAN 2.0C
C.CAN 2.0B,CAN 2.0C
D.CAN 2.0A,CAM 2.0B
第6题：
The price you quoted is so high that we () help ()this transaction.
A、can…to cancel
B、can't...canceling
C、can…canceling
D、can't…to cancel
第7题：
A.Can’tcahngeapplication’sdeploymenttargets
B.Can’tcahngeapplication’ssecuritymodel
C.Can’tcahngeapplication’snodemanager
D.Can’tcahngeapplication’spersistentstoresettings
第8题：
文中（ 3 ）处正确的答案是（ ）。
A．/etc/dhcpd.conf
B．/etc/dhcp.conf
C．/networks/dhcpd.conf
D．/networks/dhcp.conf
第9题：
（72）
A．computers
B．routers
C．switches
D．networks
第10题：
B./usr/sbin/dhcp
C./etc/networks/dhcp
D./usr/sbin/dhcpd