The National Internet Backbone is the national broad based access network to provide nodes for Internet access through out the country. The objective of the backbone is to build a country wide network to provide convenient & easily accessible Internet Access points ( IAPs) for BSNL Internet Service Providers (ISP) as well as private ISPs so that they can connect their point of presence (POP) to the Internet quickly Presently 549 IAP stations are to be connected across the country.

Network Architecture :-

The NIB consists of a multi-tier structure of aggregation & connectivity at three different levels.

The first tier consists of metropolitan & major cities ( Type A) connected by high capacity links to gateways.   Around 14 cities have been recognized as Type A. Six cities with International gateway & rest eight cities without International gateway.

The second tier (B) consists of 31 medium sized towns which are connected with first tier by medium capacity links.

A total 376 district headquarters including small towns comprise the third tier ( Type C) & are planned to be connected to the second tier to the network in the final stage. Type C locations have been further segregated into CI- 41 , CII- 87 cities &  rest CIII.

Link between Major Stations

The network architecture for these stations is with “Mesh Topology” connecting the core A1 stations The core backbone is of 8 Mbps that can be upgraded to E3 or STM-1 Each of the A2 station will be connected to two A1 stations with 2 Mbps links to E3. Each B station is to connected to two A1 or A2 stations with 2 Mbps links. The type C station will be connected to A1/A2 or B station.