Architectural Interactions of I/O Networks and Inter-networks

Philip Buonadonna, University of California, Berkeley

Recent industrial efforts (i.e. Infiniband) into next-generation System Area Networks (SAN) architectures introduce new communication abstractions and protocols coupled with significant hardware support to meet performance goals of low latency, low host processor overhead and high throughput. They largely abandon existing network protocol schemes under that the perception that they cannot deliver sufficient performance. However, the success and ubiquity of TCP/IP based networks cannot be ignored. The suite of Internet protocols is well understood, offers a rich feature set and has been tested on a variety of platforms and links. This talk examines the potential architectural interactions of regimes of new I/O networks, like Infiniband, and internet protocols in the SAN space. The first part of the discussion focuses on the Queue Pair memory-based communication adopted by modern SAN proposals. The analysis includes network performance and host overhead analysis. Also examined is the functional integration of the QP into distributed I/O and IPC application environments. The second part of the talk looks at the merger of inter-network protocols (i.e. TCP/UDP/IP) and the queue-pair abstraction in an architecture called Queue Pair IP (QPIP). Presented is a prototype implementation of QPIP that provides offloaded TCP/IP functionality underneath the QP abstraction and includes a performance analysis in the context of networked storage.