About ipfs download strategy?

if A、B、C three node has same content,The current design strategy is to download from the nearest node, or at the same time from three nodes?thanks!!

If you are using a public network you can easily get the content automagically by:

ipfs get $HASH

This should get the content from all of them.

But, I suggest to connect directly to these nodes, and if you are using a private network, you need few extra step to ensure that the private key is there and configured correctly.