Obviously SIP is considerably better than H.323 and complies with the understanding of IP-telephony as a global mass IP-service, and it should be implicitly considered right this way. And as SIP is able to serve not only telephony but also any communications at all in the real time over the IP-protocol; obviously it should become a base for other IP-services not yet existing but will appear in the future, as well.
Dialtel is an International Wholesale and Retail Carrier. We mostly focus on destinations in Africa, Middle East and Asia. Attached I am sending our Push list. Please check it and let me know whether you can use any of the routes.