Relay transactions and blocks how to and rules

[Anubis13]

I would like to understand more how the network, specially a node decides about which transactions will relay and which blocks and how it does achieve that. Is there something more than the wiki I can read?

Also I have not understood. Messages are the first thing a client does when connection to the network and after it has the info it needs it starts relaying? Also is it possible for a node not to relay blocks and transactions?

[DannyHamilton]

I would like to understand more how the network, specially a node decides about which transactions will relay and which blocks and how it does achieve that. Is there something more than the wiki I can read?

http://bitcoin.org/bitcoin.pdf

Messages are the first thing a client does when connection to the network and after it has the info it needs it starts relaying?

I'm not sure why this detail matters to you.  It would be better to ask about what you actually want to know. How will this information be useful?

If you really want to know, you can look at the source code here:
https://github.com/bitcoin/bitcoin

If you aren't able to read the source code, then again I ask, "Why do you want to know?"

Also is it possible for a node not to relay blocks and transactions?

Yes, but why?

[Sonny]

Also is it possible for a node not to relay blocks and transactions?

Yes, but why?

Maybe someone want to minimize the bandwidth usage?