How many peers can each node be connected to simultaneously? Is the maximum the same as the number of full nodes on the Monero network? Are there any performance benefits of limiting the number of peers of a full node?
A node will connect to up to 8 peers by default (P2P_DEFAULT_CONNECTIONS_COUNT in src/cryptonote_config.h). I think there is no set limit of incoming connections, though if a lot of peers try to connect, you might end up hitting your open files quota.
The more peers you are connected to, the more traffic you will have to propagate blocks and transactions. If many of those peers are not up to date and are syncing historical blocks, then you will be sending a lot of data. The upload and download rates can be throttled via the
--limit-rate-down bitmonerod command line switches (adjustable at runtime in the daemon console with
You can set the number of your daemon outgoing peers (ie, peers it connects to) with the command line parameter
--out-peers. The default is 8.
For having incoming peers, you need to open up your firewall for your daemon's p2p port (typically 18080). I think you cannot limit the number of incoming connections.
For limiting the traffic for all of these connections, see @user36303's answer.