12

Application 

Application 

OS Communication Interface 

VI Consumer 

OS Communication Interface 

VI Consumer 

Socket, MPI, Cluster, others 

Socket, MPI, Cluster, others 

VI User Agent 

VI User Agent 

Open/Connect 

Open/Connect 

Send/Receive 

Send/Receive 

Register Memory 

Register Memory 

RDMA Read/Write 

RDMA Read/Write 

User Mode 

User Mode 

VI 

VI 

VI 

VI 

VI 

VI 

CQ 

CQ 

Kernel Mode 

Kernel Mode 

VI Kernel Agent 

VI Kernel Agent 

VI Provider 

VI Provider 

Network Interface Controller 

Network Interface Controller 

Fig. 2.3. Virtual Interface Architecture

framework [30]. The VI enables direct message transfer to the NIC without requiring

to copy data to the kernel space or using the NIC driver for virtual to physical memory

translations. An application sends a request to the VI enabled API, also called as VIPL.

The VIPL formats the request, creates a VI queue or work queue pair, and submits

it directly to the NIC, which has VI enabled buffers to hold the data that is sent or

received. VIA uses a doorbell structure to initiate message transfer to/from a network.

Recently, a new VIA style communication mechanism, called InfiniBand Architec 

ture [45], has been proposed for faster access to the Network Interface. In the InfiniBand

specifications, a Host Channel Adapter (HCA) is used by the host processor to connect

to an IBA network, and has the required user level communication mechanism [45, 20].

Unlike the traditional NICs, the HCA is planned to reside in the memory controller to

avoid the PCI bus limitation [45]. Although the first generation of HCAs will probably