The Research And Implementation Of High-Speed Nic’s Data-Transmission

With the rapid development of the network and the popularisation of computers, network bandwidth and traffic are growing rapidly, especially in recent years, the network bandwidth has been reached the10Gigabit level by the application of optical fiber wideband. The increasing of network bandwidth puts forward higher request to NIC,so, high-speed NIC arises at the historic moment.But,because of data-copy,interrupt-overhead and system-call,the high-speed NIC Oftencannot achieve the expected performance.Hence, We urgently need to improve the high-speed NIC’s data-transmission mechanism and offer a reliable package system for firewall,router,IDS and other network test application.Device-polling,NAPI,ZERO-COPY are improved measures for high-speed NIC’s data-transmissionmechanism,thay can reduce the consumption of system resources in the processof data transmission.Based on ZERO-COPY and NAPI,Luca Deri developed pfring,which creating a protocol stack with cache in the kernel and improving theway of traditional kernel protocol stack processing data packets.On PFRING’s basis,this paper brings forward The Mechanism of high-speedNIC’s data-transmission based on DNA.The DNA allows applications in user space access NIC directly through letting NIC’s registers mapping into user mode.Then,the mechanism of DNA avoids mutually exclusive operations between kernel mode and user mode in the process of data-transmission,enabling the user program to more effective and convenient to manage the data buffer.Furthermore,the PFRING’s ring buffer doesn’t save the raw packets any more,but only save the address of the raw packets.At last,we design adaptive NAPI to let the modeof packet transmission can swatch flexibly with the change of network traffic.Through the above several kinds of technology,the efficiency of high-speed NIC’sdata-transmission is improved.This paper references relevant literature at home and abroad,through the study of high-speed NIC’s correlated technique and Linux kernel network structure.Then, we improve the mechanisms of high-speed NIC’s data-transmission and re ally achieve ZERO-COPY.That’s what promoting the performance of NIC’s datapacket I/O. In this paper, the main work includes the following several aspects:(1)Theoretical research part,first of all,this paper introduced the related technology of high-speed NIC’s data-transmission, analysised the I/O process of NIC’s data-transmission.Then we researched the Linux network structure and the driver of the NIC.After this,we researched the ways how to improved the efficiency and performance of NIC’s data-transmission,especially for the mechanism ofPFRING.Through research,we knew the theory and achievement of PFRING.Atlast,we analysised the defect of PFRING and pointed out the improving measures,came up with The Mechanism Of High-Speed NIC’s Data-Transmission BasedOn DNA.(2)Practical research part,detailed introduced the DNA mechanism’s realization process,including letting NIC’s register mapping into user space,improving DMA circle buffer,improving PFRING circle buffer,realizing adaptive NAPI.At last,we configured test environment and tested DNA’s performance.Then it turned outThe Mechanism Of High-Speed NIC’s Data-Transmission Based On DNA was very excellent.