Table 2.

The value of $\frac{\mathsf{\partial }T}{\mathsf{\partial }a}-\frac{\mathsf{\partial }∆T}{\partial a}$ and $\frac{\mathsf{\partial }T}{\mathsf{\partial }b}-\frac{\mathsf{\partial }∆T}{\mathsf{\partial }b}$.

$$\frac{\mathsf{\partial }\mathit{T}}{\mathsf{\partial }\mathit{a}}-\frac{\mathsf{\partial }∆\mathit{T}}{\mathsf{\partial }\mathit{a}}$$	$$\frac{\mathsf{\partial }\mathit{T}}{\mathsf{\partial }\mathit{b}}-\frac{\mathsf{\partial }∆\mathit{T}}{\mathsf{\partial }\mathit{b}}$$	Conclusion
0	0	Both layers are abnormal.
0	×	Communication layer is abnormal.
×	0	Transaction layer is abnormal.
×	×	Both layers are normal.