Measures taken when signal crosses splits

The simple answer is don't cross the split in the plane. If this is not possible, reduce your current loop to the absolute minimum. It is difficult to give a solution without knowing a lot more about your design. A bypass capacitor between the two planes at the point where you are crossing the split will help. Guardbanding is another way to maintain a small current loop.
Regards,
hpattie@entrisphere.com

Thanks for you suggestion. But what will be the value of decap and why

The problem with crossing a split plane is that the return current cannot cross the split so it takes some longer path which adds inductance to your signal (i.e. slows it down) and the convoluted return path usually results in excess emissions (EMI). The faster your edge rate, the more you need to worry. I2C is OK, 800MHz DDR2 is not. Crossing a split plane will probably kill your DDR2 signal, especially if both reference planes are split.

There are quite a good number of articles written on this topic, that you can find on the net. One good source to start with is Eric Bogatin's site at:
www.bogatinenterprises.com

Best regards,
Kishore

Thanks for the reply