Also notice how the ID of this diagram indicates that this is alternate course B.

另外还请注意该图的标识是如何表示这是一个备选过程B。

youdao

A two - (or more) cell strategy provides the capability to divert traffic to an alternate cell (cell b) while maintenance is being applied to a primary cell (cell a).

在您对主要单元(单元a)进行维护时，一个两单元(或者多单元)策略可以使流量转移到一个可替换的单元(单元b)。

youdao

Back in the days of the Soviet Union, our intelligence agencies employed Team A and Team B to provide alternate calculations of Soviet military might.

FORBES: Are CBO Estimates Really The Gold Standard Of Accuracy?