An I/O device includes a host interface coupled to a plurality of hardware resources. The host interface includes a transaction layer packet (TLP) processing unit that may receive and process a plurality of transaction layer packets sent by a plurality of processing units. Each processing unit may correspond to a respective root complex. The TLP processing unit may identify a transaction type and a processing unit corresponding to each transaction layer packet and store each transaction layer packet within a storage according to the transaction type and the processing unit. The TLP processing unit may select one or more transaction layer packets from the storage for process scheduling based upon a set of fairness criteria using an arbitration scheme. The TLP processing unit may further select and dispatch transaction layer packets for processing by downstream application hardware based upon additional criteria.