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．

（72）处应填（）。

A．computers

B．routers

C．switches

D．networks

BOT模式的主要内容包括( )等。

A．项目公司以同政府签订的“特许权协议”作为项目建设开发和安排融资的基础

B．项目公司将特许权协议等权益转让给贷款银团作为抵押，并提供其他信用担保，安排融资

C．项目公司有权不受任何时间限制地拥有并经营项目设施

D．工程承包商与项目公司签订承包合同进行项目建设，并提供完工担保

E．项目公司代表了一种居中的民营化程度