Abstract: Regeneration code technique has been widely used in the field of data storage with the advantages of high fault tolerance and low redundancy overhead, but the redundancy technique based on regeneration codes needs to download multiple coded blocks from other providers for repairing the failed data. Considering the heterogeneity of link bandwidth between nodes, the available bandwidth capacity of links varies greatly in real networks, minimization of network traffic does not necessarily imply minimization of regeneration time. Moreover, existing regeneration code repair schemes for bandwidth heterogeneity are difficult to support exact repair regeneration codes. Due to the specific mathematical structure of exact repair regeneration codes, their parallel repair is difficult to achieve. Therefore, ERC-TREE is proposed as a repair framework for exact repair regeneration codes under bandwidth heterogeneous networks. This framework efficiently takes advantage of the available bandwidth between providers by constructing an optimal tree to achieve exact repair of failed node data. The simulation experiment shows the feasibility of tree repair for exact repair regeneration codes in heterogeneous bandwidth environments. In the scenario with a significant difference in bandwidth, ERC-TREE reduces the data repair time by 78% compared to star repair. 

Key words: regeneration code, data storage, heterogeneous network, tree repair, exact repair