Routing protocols use different techniques for assigning(71)to individual networks. Further, each routing protocol forms a-metric aggregation in a different way. Most routing protocols can use multiple paths if the paths have an equal(72).Some routing protocols can even use multiple paths when paths have an unequal cost. In either case,load (73)can improve overall allocation of network bandwidth. When multiple paths are used, there are several ways to distribute the packets. The two most common mechanisms are per-packet load balancing and per-destination lad balancing. Per-packet load balancing distributes the(74)across the possible routes in a manner proportional to the route metrics. Per-destination load balancing distributes packets across the possible routes based on(75).

73（）

A．bracketing

B．balancing

C．downloading

D．transmitting

在机电安装工程中常用的钢管有（）等。

A.无缝不锈钢管

B.螺旋缝钢管

C.低压无缝钢管

D.高压无缝钢管

E.焊接钢管