Routing a data packet of an information unit sequence includes receiving at a switch a data packet of an information unit sequence of a block storage exchange from a storage client, where the sequence is associated with a source identifier and a target identifier identifying a target. A storage resource identifier corresponding to the target identifier is determined according to a forwarding table. A sequence identifier is associated with the source identifier, where the sequence identifier corresponds to the target. The source identifier and the sequence identifier are recorded at a context table, and the data packet is routed according to the storage resource identifier.