【3】 技术是将数据和行为看成是一个统一的整体,使一个软件成分,即所谓的对象。
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One of the most widely used routing protocols in IP networks is the Routing Information Protocol(RIP).RIP is the canonical example of a routing protocol built on the (71) algorithm.Routing protocols in internetworks differ slightly from the idealized graph model.In aninternetwork,the goal of the routers to forward packets to various (72) . Routers running RIP send their advertisement about cost every (73) seconds.A router also sends an update message whenever an update from another router causes it to change itsrouting table. It is possible to use a range of different metrics or costs for the links in a routing protocol.RIP takes the simplest approach,with all link costs being equal (74) Thus it always tries tofind the minimum hop route.Valid distances are 1 through (75) .This also limits RIP torunning on fairly small networks.
A. 10
B. 30
C. 60
D. 180
传统的Internet提供的是没有QoS保证的、尽力而为的服务。其实在lPv4包中已经定义了服务类型字段,包括优先级、吞吐量、延迟、可靠性等,只要 (23) 处理该字段,就可提供QoS保证。MPLS是一种更通用的QoS保证机制,其基本思想可简述为 (24) 。
A. 标记交换路由器为IP分组加上标记,其他路由器按优先级转发
B. 边缘路由器对业务流进行分类并填写标志,核心路由器根据分组的标志将其放入不同的队列转发
C. 在建立连接时根据优先级预留所需要的资源以提供所要求的QoS
D. 根据IP分组中自带的优先级信息对IP分组进行排队,保证高优先的分组优先转发
One of the most widely used routing protocols in IP networks is the Routing Information Protocol(RIP).RIP is the canonical example of a routing protocol built on the (71) algorithm.Routing protocols in internetworks differ slightly from the idealized graph model.In aninternetwork,the goal of the routers to forward packets to various (72) . Routers running RIP send their advertisement about cost every (73) seconds.A router also sends an update message whenever an update from another router causes it to change itsrouting table. It is possible to use a range of different metrics or costs for the links in a routing protocol.RIP takes the simplest approach,with all link costs being equal (74) Thus it always tries tofind the minimum hop route.Valid distances are 1 through (75) .This also limits RIP torunning on fairly small networks.
A. 6
B. 10
C. 15
D. 16
以下程序中函数scmp的功能是返回形参指针s1和s2所指字符串中较小字符串的首地址。 #include<string> char*scmp(char*s1,char*s2) if(strcmp(s1,s2)<0) return(s1); else retrun(s2); main() int i;char string[20],str[3][20]; for(i=0;i<3;i++)gets(str[i]); strcpy(string,scmp(str[0],str[1]));//库函数strcpy对字符串进行复制 strcpy(string,scmp(string,str[2])); puts(string) 若运行时依次输出:abcd、abba和abc三个字符串,则输出结果为( )。
A. abcd
B. abba
C. abc
D. abca