- Determine ip and mac header information for a data packet frame drivers#
- Determine ip and mac header information for a data packet frame driver#
It is computed as the 16 bit one's complement of the one's Complement sum of all 16 bit words in the header. It is computed using the following algorithm.Ģ.1.2 IPv4 header Checksum computation algorithm: The sender of the IPv4 packet is required to compute the checksum value for the IP header fields and insert in the "header checksum' field.
The header checksum field is needed to ensure the integrity of the IP header. The detailed descriptions for the header fields can be found in RFC 791. The 2 versions are IPv4 and IPv6.Ģ.1.1 IPv4 datagram frame format: The following diagram shows the IPv4 frame format. In our application, this is encapsulated in the Ethernet MAC frame. IP (Internet Protocol) is a layer-3 protocol that contains packet routing information like addressing and routing controls. Technical Overview of the Checksum Functionality: This article is intended to give a brief overview of the checksum feature for IPv4, TCP/UDP protocols and introduce its implementation in the GMAC Universal IP.Ģ. Now additional enhancements like TCP/UDP checksum handling have been implemented to further help the SoCs in computing checksum in hardware. Synopsys' DWC Ether MAC 10/100/1000 - universal IP in its current GA release, 3.20a implements the checksum-hardware-assist function by providing the IPv4 header checksum checking and payload checksum computation.
Determine ip and mac header information for a data packet frame drivers#
This functionality can be enabled in Asics and disabled in the existing drivers (TCP/IP protocol stack) easily.
Determine ip and mac header information for a data packet frame driver#
The checksum offload feature can be implemented as a combination of hardware and software functions - the hardware assists the driver in completing the checksum computation. In an attempt to improve performance and to assist drivers in ensuring data integrity, checksum computation is increasingly being done in hardware. This results in the overall under-utilization of the network and hence degraded performance. However, with gigabit and 10Gbps interconnect speeds of moving data, computation of checksum using software drivers becomes a huge burden on the CPU - this is one of the most demanding tasks on the host, leaving less cycles for application processing.
Typically in fast Ethernet systems this computation is done by the driver software running on the CPU. Similarly the TCP/UDP data which forms the payload for the IP datagram would have its checksum computed and embedded as a part of the TCP/UDP frame. The receiver would also compute the checksum locally and based on the result ascertain the data integrity. The sender of an IPv4 datagram would compute the checksum value based on the data and embed it in the frame. Communication protocols like TCP/IP/UDP implement this scheme in order to determine whether the received data is corrupted along the network. IntroductionĬhecksum is a simple error detection mechanism to determine the integrity of the data transmitted over a network. IP and TCP/UDP Checksum Offload Functionality and its Support in Synopsys' DesignWare Ethernet MAC 10/100/1000 - Universal Core 1.
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