What is 'validity period' and 'claim period' in a bank guarantee?

Banks always specify the period for which their guarantee subsists and an additional period during which a claim has to be made on the bank to make payment. The former period during which the guarantee subsists is called the 'validity period' and latter, the 'claim period'. If any default has been committed by the debtor (i.e. the bank's customer) it should be within the validity period. The bank should specifically indicate the period for which the guarantee is valid. The guarantee should also indicate the claim period, usually beyond the validity period. Invocation should have been made within the validity period. The claim period is usually a few months beyond the validity period of the guarantee and it is preferred to mention the exact period and time of grace.