but y routiing is not done thru shortest path..i mean for US server y does it route thru hongkong?
n in tracert when i c analysis it tells slow response after a particular hop n that hop is generally reliance or
tata
This is because Tata, Reliance and Bharti own all the transit cables from India to the rest of the world.
Its because the primary route is faulty and they are trying to fix it.
I'm on BSNL and my data travels to Tokyo first and then to USA. (just because the primary route is down)
Depends where the server is located as to how your traffic travels.
As far as I know, MTNL-BSNL, both don't have their own routing. They rent it from the big players like Airtel, TATA Communications (VSNL) and Reliance.
And the CAT B ISP, It might be a name used for their specific exchange/equipment routing area/place, something like that.
A Category B ISP is an ISP which holds a license to service only specific circles - basically speaking MTNL Mumbai can only offer services in Mumbai, and MTNL Delhi can only offer services in Delhi. They can't offer services in Tamil Nadu, for example.
A category A ISP is allowed to service anywhere in the country. BSNL, Bharti, Reliance, Tata, Hathway and Sify are all Category A ISPs from memory - but there are quite a few others.