📨Messaging Latency and Cost

Messaging

• The Rollup allows for seamless communication with Layer 1, enabling the transmission of arbitrary messages.

• Each protocol ensures the verifiable transfer of data to the intended chain.

Latency from L1 to L2:

• This refers to the duration required for a message to become accessible on the Rollup once it's included in an Ethereum block.

Cost from L1 to L2:

• The expense involved in sending a message from Ethereum to the Layer 2 Rollup.

• The Rollup processes the message using a system address, acting on behalf of the original sender from Layer 1.

• The sender on Layer 1 bears the cost of Layer 2 gas for message execution.

Latency from L2 to L1:

• This is the time taken for a message to be available on Ethereum after it’s recorded in a Rollup block and sequenced to Layer 1.

Cost from L2 to L1:

• The gas expense incurred for the verification and initiation of message execution on Ethereum, following its dispatch from the Rollup.

• This cost is covered by the Externally Owned Account (EOA) that triggers the claim transaction on Layer 1.

• It's important to note that this cost does not include the expenses arising from the operations performed as a result of the message.

Messaging	OP Mainnet (Optimistic, EVM)	Base (optimistic, EVM)	Linea (zk, EVM)	Arbitrum One (Optimistic, EVM)	Polygon zkEVM	zkSync Era (ZK, EVM)
L1 → L2 Latency	~1 minute	~1 minute	~17min	~6-9 minutes	~6-8 minutes	~2 minutes
L1 → L2 Cost	~38 000 L1 gas	~43 000 L1 gas	~66 000 L1 gas + ~71 000 L2 gas (in case of manual delivery)	No added cost	95000 L2 gas	No added cost
L2 → L1 Latency	7 days	7 days	8 to 32 hours	7 days	~1 hour	-
L2 → L1 Cost	600 000 L1 gas	600 000 L1 gas	~73 000 L2 gas*	60 000 L1 gas	95000 L1 gas	-

*On Linea