单选题局域网中某主机的IP地址为176.16.1.12/20，该局域网的子网掩码为 (55) ，最多可以连接的主机数为 (56) 。

单选题用扩展访问控制列表配置封禁ICMP协议，只允许168.27.95.0/24子网的ICMP数据包通过路由器，正确的配置是______。 A．access-list 90 deny icmp 168.27.95.0 255.255.255.0 any access-list 90 deny icmp any any access-list 90 permit ip any any B．access-list 100 permit icmp 168.27.95.0 0.0.0.255 any access-list 100 permit ip any any C．access-list 110 permit icmp 168.27.95.0 255.255.255.0 any access-list 110 deny icmp any any D．access-list 120 permit icmp 168.27.95.0 0.0.0.255 any access-list 120 deny icmp any any access-list 120 permit ip any any

单选题以下属于《综合布线系统工程设计规范GB50311-2007》的强制性条文的是______。

单选题下列概念中不属于成本管理环节的是 (10) 。 A．成本决策 B．成本控制 C．成本分析 D．系统运行管理

单选题如果主存容量为512MB，且按字节编址，则该主存地址至少需要______位。 A．29 B．218 C．227 D．229

单选题下列有关网络拓扑结构的叙述中，不正确的是 (18) 。

单选题ARP 协议数据单元封装在（ ）中传送

单选题Skype融合的两大技术是VoIP和( )。 A．C/S B．IPTV C．B/S D．P2P

单选题对高级语言源程序进行编译或解释的过程可以分为多个阶段，解释方式不包含______。

单选题某主机本地连接属性如图所示，下列说法中错误的是______。

单选题新交换机出厂时的默认配置是 (58) 。 A．预配置为VLAN1，VTP模式为服务器 B．预配置为VLAN1，VTP模式为客户机 C．预配置为VLAN0，VTP模式为服务器 D．预配置为VLAN0，VTP模式为客户机

单选题在安全通信中,A 将所发送的信息使用（ ）进行数字签名,B 收到该消息后可利用（ ）验证该消息的真实性

单选题______能够显示路由器配置了哪种路由协议。 A．R1(config)#show ip route B．R1＞show ip route C．R1＞show ip protocol D．R1>(config—if)#show ip protocol

单选题下面的地址中，属于本地环路地址的是______。 A．10.10.10.1 B．255.255.255.0 C．127.0.0.1 D．192.0.0.1

单选题Border Gateway Protocol (BGP) is inter-autonomous system (71) protocol. BGP is based on a routing method called path vector routing. Distance vector routing is not a good candidate for inter-autonomous system routing because there are occasions on which the route with the smallest (72) count is not the preferred route. For example, we may not want a packet through an autonomous system that is not secure even though it is the shortest route. Also, distance vector routing is unstable due to the fact that the routers announce only the number of hop counts to the destination without actually defining the path that leads to that (73) . A router that receives a distance vector advertisement packet may be fooled if the shortest path is actually calculated through the receiving router itself. Link (74) routing is also not a good candidate for inter-autonomous system routing because an internet is usually too big for this routing methoD. To use link state routing for the whole internet would require each router to have a huge link state database. It would also take a long time for each router to calculate its routing (75) using the Dijkstra algorism.

单选题下列关于线程的叙述正确的是 (32) 。

单选题在异步通信中，每个字符包含1位起始位、7位数据位、1位奇偶位和1位终止位，每秒钟传送200个字符，采用DPSK调制，则码元速率为______，有效数据速率为______。

单选题以下Linux命令中，用于退出当前shell的命令是______。

单选题有关曼彻斯特码编码的正确叙述是 (24) 。