What extra complexities may arise if the messages can be adaptively rerouted on the links? For example, a coherency message from core M1 directory controller to C2 (expressed in binary as M₀₀₁ -->C₀₁₀)will be routed either through the inter-node path C₀₀₁-->C₀₀₀-->C₀₁₀ or the inter-node path C₀₀₁-->C₀₁₁-- > C₀₁₀, depending on link availability