askhello 2008-4-3 22:44
关于rip负载均衡的一道题，谁能解释一下呀？
[size=3]The Testking [url=http://whatis.ctocio.com.cn/searchwhatis/367/6093367.shtml]network[/url] is utilizing [url=http://whatis.ctocio.com.cn/searchwhatis/182/6093682.shtml]RIP[/url] as the [url=http://whatis.ctocio.com.cn/searchwhatis/191/6025691.shtml]IP[/url] routing [url=http://whatis.ctocio.com.cn/searchwhatis/343/6026343.shtml]protocol[/url]. Router TK1
learns how to [url=http://whatis.ctocio.com.cn/searchwhatis/27/6093527.shtml]reach[/url] the same destination via 6 different paths. All paths have the
same [url=http://whatis.ctocio.com.cn/searchwhatis/230/5948730.shtml]metric[/url] and administrative distance. With all routers using the default
operation, which of the paths will be chosen to reach the destination?[/size] [size=3]A. Only the first two paths that are learned.
B. Four of the paths.
C. All six routes in a routed robin fashion.
D. The oldest two paths in the [url=http://whatis.ctocio.com.cn/searchwhatis/239/6093739.shtml]routing[/url] table.
E. The first [url=http://whatis.ctocio.com.cn/searchwhatis/448/6025948.shtml]path[/url] learned to the destination network.
[/size]
[size=3]答案是: E， 请高人解释一下吧！[/size]
netload 2008-4-9 18:37
RIP的解释
RIP(Routing information Protocol)是应用较早、使用较普遍的内部网关协议(Interior Gateway Protocol,简称IGP)，适用于小型同类网络，是典型的距离向量(distance-vector)协议。文档见RFC1058、RFC1723。
RIP通过广播UDP报文来交换路由信息，每30秒发送一次路由信息更新。RIP提供跳跃计数(hop count)作为尺度来衡量路由距离，跳跃计数是一个包到达目标所必须经过的路由器的数目。如果到相同目标有二个不等速或不同带宽的路由器，但跳跃计数相同，则RIP认为两个路由是等距离的。RIP最多支持的跳数为15，即在源和目的网间所要经过的最多路由器的数目为15，跳数16表示不可达。
askhello 2008-4-10 18:21
标准的 Explanation！
By default, RIP only maintains one entry for each destination, and does not load balance
over equal cost paths.
To set the maximum number of routes that RIP can insert into the routing table, use the
rip equal-cost command. Enter a number from 1 to 15. The default is 1. For example:
(config)# rip equal-cost 4
To reset the number of routes to the default value of 1, enter:
(config)# no rip equal-cost
Again, the default is one, so only the first path to the destination will be kept in the
routing table of TK1.