Does Ice provide such services as OTS(Object Transaction Service) ?

Ice does not provide a fully fledged distributed transaction service. You can use transactions in conjunction with the Ice Freeze component, but this does not support distributed transactions. Should you really need such a feature and you wish to sponsor commercial development of this please contact us at sales@zeroc.com.

Keep in mind that distributed transactions are really expensive in comparison with non-distributed transactions and non-transactional applications. Many applications do not in fact need DTS so it would be worthwhile examining your application architecture to find out whether for your case it is really necessary.