Constant solana_sdk::packet::PACKET_DATA_SIZE

pub const PACKET_DATA_SIZE: usize = 1280 - 40 - 8; // 0x0000_0000_0000_04d0usize

Maximum over-the-wire size of a Transaction 1280 is IPv6 minimum MTU 40 bytes is the size of the IPv6 header 8 bytes is the size of the fragment header