# Polkadot <> Kusama Bridge

Our bridge connects two parachains - Kusama Bridge Hub and Polkadot Bridge Hub. Messages that are sent over bridge have XCM format and we are using existing architecture to dispatch them. Since both Polkadot, Kusama and their parachains already have means to exchange XCM messages within the same consensus system (HRMP, VMP, ...), it means that we are able to connect all those chains with our bridge.

In our architecture, the lane that is used to relay messages over the bridge is determined by the XCM source and destinations. So e.g. bridge between Asset Hubs Polkadot and Kusama (and opposite direction) will use the lane 00000000, bridge between some other Polkadot Parachain and some other Kusama Parachain will use the lane 00000001 and so on.

flowchart LR subgraph Polkadot Consensus polkadot(((Polkadot))) asset_hub_polkadot(((Polkadot Asset Hub))) polkadot_bh(((Polkadot Bridge Hub))) polkadot---asset_hub_polkadot polkadot---polkadot_bh asset_hub_polkadot-->|Send Message Using HRMP|polkadot_bh polkadot_bh-->|Send Message Using HRMP|asset_hub_polkadot asset_hub_polkadot-->|Dispatch the Message|asset_hub_polkadot end subgraph Kusama Consensus kusama_bh(((Kusama Bridge Hub))) asset_hub_kusama(((Kusama Asset Hub))) kusama(((Kusama))) kusama---asset_hub_kusama kusama---kusama_bh kusama_bh-->|Send Message Using HRMP|asset_hub_kusama asset_hub_kusama-->|Dispatch the Message|asset_hub_kusama asset_hub_kusama-->|Send Message Using HRMP|kusama_bh end polkadot_bh<===>|Message is relayed to the Bridged Chain using lane 00000000|kusama_bh linkStyle 2 stroke:red linkStyle 7 stroke:red linkStyle 8 stroke:red linkStyle 3 stroke:green linkStyle 4 stroke:green linkStyle 9 stroke:green