A Single-Buffered （SB） router is a router where only one stage of shared buffering is sandwiched between two interconnects in comparison of a Combined Input and Output Queued （CIOQ） router where a central switch f...A Single-Buffered （SB） router is a router where only one stage of shared buffering is sandwiched between two interconnects in comparison of a Combined Input and Output Queued （CIOQ） router where a central switch fabric is sandwiched between two stages of buffering. The notion of SB routers was firstly proposed by the High-Performance Networking Group （HPNG） of Stanford University, along with two promising designs of SB routers： one of which was Parallel Shared Memory （PSM） router and the other was Distributed Shared Memory （DSM） router. Admittedly, the work of HPNG deserved full credit, but all results presented by them appeared to relay on a Centralized Memory Management Algorithm （CMMA） which was essentially impractical because of the high processing and communication complexity. This paper attempts to make a scalable high-speed SB router completely practical by introducing a fully distributed architecture for managing the shared memory of SB routers. The resulting SB router is called as a Virtual Output and Input Queued （VOIQ） router. Furthermore, the scheme of VOIQ routers can not only eliminate the need for the CMMA scheduler, thus allowing a fully distributed implementation with low processing and commu- nication complexity, but also provide QoS guarantees and efficiently support variable-length packets in this paper. In particular, the results of performance testing and the hardware implementation of our VOIQ-based router （NDSC~ SR1880-TTM series） are illustrated at the end of this paper. The proposal of this paper is the first distributed scheme of how to design and implement SB routers publicized till now.展开更多
The overhead in iSCSI subsystems is analyzed through the model of iSCSI reading and writing requests. An analytic model of iSCSI subsystem overhead is developed. According to the analytic model, the overhead of iSCSI ...The overhead in iSCSI subsystems is analyzed through the model of iSCSI reading and writing requests. An analytic model of iSCSI subsystem overhead is developed. According to the analytic model, the overhead of iSCSI subsystems is measured, which reveals that the main overhead is caused by protocol processing as well as kernel functions for fair allocation of system resources. Several methods have been proposed to optimize iSCSI subsystems, such as small I/O requests adherent that can be merged into a large I/O request. Checksum is found to be a time consuming work and may not be always necessary for applications.展开更多
基金the National High-Tech Research and De-velopment Program of China (863 Program) (2003AA103510, 2004AA103130, 2005AA121210).
文摘A Single-Buffered （SB） router is a router where only one stage of shared buffering is sandwiched between two interconnects in comparison of a Combined Input and Output Queued （CIOQ） router where a central switch fabric is sandwiched between two stages of buffering. The notion of SB routers was firstly proposed by the High-Performance Networking Group （HPNG） of Stanford University, along with two promising designs of SB routers： one of which was Parallel Shared Memory （PSM） router and the other was Distributed Shared Memory （DSM） router. Admittedly, the work of HPNG deserved full credit, but all results presented by them appeared to relay on a Centralized Memory Management Algorithm （CMMA） which was essentially impractical because of the high processing and communication complexity. This paper attempts to make a scalable high-speed SB router completely practical by introducing a fully distributed architecture for managing the shared memory of SB routers. The resulting SB router is called as a Virtual Output and Input Queued （VOIQ） router. Furthermore, the scheme of VOIQ routers can not only eliminate the need for the CMMA scheduler, thus allowing a fully distributed implementation with low processing and commu- nication complexity, but also provide QoS guarantees and efficiently support variable-length packets in this paper. In particular, the results of performance testing and the hardware implementation of our VOIQ-based router （NDSC~ SR1880-TTM series） are illustrated at the end of this paper. The proposal of this paper is the first distributed scheme of how to design and implement SB routers publicized till now.
基金Funded by National Network and Security Continuous Developing Plan (2004 Research 1-917-021)
文摘The overhead in iSCSI subsystems is analyzed through the model of iSCSI reading and writing requests. An analytic model of iSCSI subsystem overhead is developed. According to the analytic model, the overhead of iSCSI subsystems is measured, which reveals that the main overhead is caused by protocol processing as well as kernel functions for fair allocation of system resources. Several methods have been proposed to optimize iSCSI subsystems, such as small I/O requests adherent that can be merged into a large I/O request. Checksum is found to be a time consuming work and may not be always necessary for applications.
