The Border Gateway Protocol (BGP) is an interautonomous system (28) protocol. The primary function of a BGP speaking system is to exchange network (29) information with other BGP system. This network reachability information includes information on the list of Autonomous System (ASs) that reachability information traverses. BGP-4 provides a new set of mechanisms for supporting (30) interdomain routing. These mechanisms include support for advertising an IP (31) and eliminate the concept of network class within BGR BGP-4 also introduces mechanisms that allow aggregation of routes, including. (32) of AS paths. These changes provide support for the proposed supernettting scheme.

A. reservation B. relation C. aggregationD. connection

创建“student.mdb”数据库，将考生文件夹中的“student.txt”导入到数据库中，第一行包含列标题，学生ID为主键，导入表的名字为“student”。
(2)设置“student”表单元格效果为“凹陷”。
(3)将“student”表的关键字取消。“student”表如图所示。