Third Party bridge

In the context of permissioned L1s ?

In the context of Rollups

When needed:

Rollups that do not share a DA layer or those that share a DA layer but have different execution layers (virtual machines) will still need to be connected via third-party messaging bridges.

Celestia rollups will need a messaging bridge to be connected to rollups built on EigenDA OR Rollup A using EVM for execution, and Rollup B using the SVM for execution, where both use Celestia for DA will still need a third-party bridge for message passing.

When not needed:

Trust-minimized cross-chain communication is possible across rollups with a common consensus and data availability (DA) layer, removing the need for third-party bridges for inter-rollup connectivity.

These rollups will maintain a native bridge with the DA layer, which will serve as a central hub linking all these chains together.

Source: @ayyyeandy from The Rollup