A serial line can only run as fast as the tightest step.

highlighted = computed this step

Minimum Step Rate

The line capacity is the smallest step rate.

line capacity=min(step rates)\text{line capacity}=\min(\text{step rates})
Capacity and slackThe table records the exact line capacity, slack, and output.capacity and slackunits/hourline capacity20slack2output18

Line Capacity

Line capacity is 20 units per hour.

capacity=20\text{capacity} = 20
Capacity and slackThe table records the exact line capacity, slack, and output.capacity and slackunits/hourline capacity20slack2output18