There are 3 Components as per connectivity goes.
1. Local loop to connect to India end Gateway. This is provided by BSNL / TATA
2. IPLC Half CCT., provided by VSNL
3. International Half cct.. provided by MCI / AT&T / XATMI (Reach) / SingTel
apart from these you need voice T1 / E1 which will connect you to local Telecom Network of that country.