BOSIBC.IO ( also know as BOS IBC ) is a Smart contract system developed by BOSCore for EOS based blockchains. It provides the function of decentralized IBC (Inter-Blockchain Communication) for EOSIO based blockchains. BOSIBC.IO smart contracts are deployed on the EOS and BOS blockchains allowing for bidirectional transfers of tokens across chains.
BOS IBC is based on SPV (Simple Payment Verification) as outlined in the EOSIO IBC Principle and Design, published by BOSCore developer Simon. The same document references Inter-Blockchain Communication via Merkle Proofs with EOSIO published by Dan Larimer, CTO at Block.One. 
The BOS IBC system contains two smart contracts, ibc.chain contract is the SPV client, the SPV client can be used as a service to verify peer chain transactions, and the ibc.token contract can be seen as a DApp by the ibc.chain contract, so BOS IBC is composed of decentralized IBC and a peg token application.