Virtual Interface Architecture: Difference between revisions

Revision as of 15:14, 8 May 2011

Revision as of 18:26, 10 August 2011

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The '''Virtual Interface Architecture''' ('''VIA''') is an abstract model of an user-level [[zero-copy]] [[computer network|network]], and is the basis for [[InfiniBand]], [[iWARP]] and [[iWARPRDMA_over_Converged_Ethernet|RoCE]]. Created by [[Microsoft]], [[Intel]], and [[Compaq]], the original VIA sought to standardize the interface for high-performance network technologies known as System Area Networks (SANs; not to be confused with [[Storage Area Network]]s).

Networks are a shared resource. In traditional networks such as [[Ethernet]], the network is protected by the [[kernel (computer science)|kernel]], which presents a tremendous performance bottleneck when [[lag|latency]] is an issue.

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For the NIC to actually access the data through DMA, the user's page must be in memory. In VIA, the user must "pin-down" its buffers before transmission, so as to prevent the OS from swapping the page out to the disk. This action—one of the few that involves the kernel—ties the page to physical memory. To ensure that only the process that owns the registered memory may access it, the VIA NICs require permission keys known as "protection tags" during communication.

So essentially VIA is a standard that defines kernel bypassing and RDMA in a network. It also defines a programming library called "VIPL". It has been implemented, most notably in cLAN from Giganet (now [http://www.emulex.com/ Emulex]). Mostly though, VIA's major contribution has been in providing a basis for the [[InfiniBand]], [[iWARP]] and [[iWARPRoCE]] standards.

==External links==