Capital gain computation on transfer of Bonds

I have some confusion on the holding period for calculating ST/LT capital Gains for Bonds. I understand that Long term gains are taxed @ 10% or 20% after indexation for all types of bonds.

What is the holding period for a Bond transfer to be considered as long term? Is it 3 years or 1 year?

Does the holding period for consideration of LT gains depend on the type of Bond? ie:

1. Zero Coupon Bond
2. Capital Indexed Bond
3. Bonds that are listed
4. All other types of bonds not listed above