Hi,

I'm proposing the addition of a new, optional p2p message to help improve the way blocks are announced on the network.  The draft BIP is available here and pasted below:

https://gist.github.com/sdaftuar/465bf008f0a4768c0def

The goal of this p2p message is to facilitate nodes being able to optionally announce blocks with headers messages rather than with inv's, which is particularly beneficial since the introduction of headers-first download in Bitcoin Core 0.10.  In particular, this allows for more efficient propagation of reorgs as it would eliminate a round trip in network communication.