chainId: Identifies blockchain, the main Ethereum chain has its own ID, but you will need to set it to a unique value for your private chain.
homesteadBlock: Homestead is the second major version of the Ethereum platform and is the first production release of Ethereum. It includes several protocol changes. So, if you are on homestead version, this attribute is 0
ByzantiumBlock: Indicates that Byzantium is enabled in your private network.
eip155Block/eip158Block: Homestead version was released with a few backward-incompatible protocol changes, and therefore requires a hard fork. These protocol changes/improvements proposed through a process Ethereum Improvement Proposals (EIPs). If your chain won’t be hard-forking for these changes leave as 0