A bond is said to be currently callable if the issue is not protected against early call provision. But most new bond issues, even if currently callable, usually have some restrictions against certain types of early redemption. The most common restriction is that of prohibiting the refunding of the bonds for a certain number of years or for the issue's life. Bonds that are non-callable for the issue's life are more common than bonds which are non-refundable for life but otherwise callable.
Call protection is much more robust than refunding protection. While there may be certain exceptions to absolute or complete call protection in some cases, call protection still provides greater assurance against premature and unwanted redemption than refunding protection. Refunding protection merely prevents redemption from certain sources, namely the proceeds of other debt issues sold at a lower cost. The holder is protected only if interest rates decline and the borrower can obtain low-cost money to pay off the debt.