Encounter中的CTS问题

最近小弟刚开始学习布局布线没多久，碰到许多问题。在一次使用Encounter时，用三层版进行布局布线的时候没什么问题，之后改用两层版，在做完CTS后发现版图内有很多红色菱形，不论怎么增加版图的面积，还是有许多。想问一下：
1.这些红色菱形是指什么错误，其中的V:16/9H:10/8之类的是代表什么意思?
2.如何才能避免这种情况?在插时钟树前有什么需要注意的吗?

1.it is visually check the congestion statistics.by trial route generate congestion.
Eg: V=44/40 H=16/18
The vertical(V) overflow is 44/40 (44 tracks are required, but only 40 tracks are available)
The Horizontal(H) overflow is 16/18 (16 tracks are required, and 18 tracks are available)
2. fix it as following step:
I. Can adjust block placements and/or orientations to make sure that connecting pins also face each other.
II.Can use a partial placement blockage to lower the congestion in a specific area.
III.Read the log file for horizontal and vertical overflow numbers(%), where 1.0% is thelimit for 5+ metal layers and 0.5% is the limit for 3 layers. These are optimal limits for proceeding to detail routing.

congestion

谢谢1楼大侠的指点，我再去试试。