tcp checksum offload

Article Source: http://hi.baidu.com/zyqq/blog/item/54bb905256546f040cf3e3a9.html In fact, this problem is often found during packet capture. Today I went to Google with curiosity. In a simple summary, the packet captured by Wireshark prompts a checksum error,It is only because it intercepts the overhead checksum of the operating system, and the Gigabit NIC will hand over the computing work to the NIC afte

DPDK rte_mbuf enable NIC Offload Compute checksum configuration method Compute IP Checksum Mb->l2_len = Len (out_eth) Mb->l3_len = Len (out_ip) mb->ol_flags |= Pkt_tx_ipv4 | Pkt_tx_ip_csum Note:Out_ip.checksum = 0The NIC supports the Dev_tx_offload_ipv4_cksum feature. Compute IP UDP checksum Mb->l2_len = Len (out_e

DPDK rte_mbuf enable NIC Offload Compute checksum configuration method Compute IP Checksum Mb->l2_len = Len (out_eth) Mb->l3_len = Len (out_ip) mb->ol_flags |= Pkt_tx_ipv4 | Pkt_tx_ip_csum Note:Out_ip.checksum = 0The NIC supports dev_tx_offload_ipv4_cksum features. Compute IP UDP checksum Mb->l2_len = Len (out_eth)

as invalid, even though the packets will contain validChecksums when they leave the network hardware later. Checksum offloading can be confusing and having a lot of [invalid]Messages on the screen can be quite annoying. As mentioned above,Invalid checksums may lead to unreassembled packets, makingAnalysis of the packet data much harder. You can do two things to avoid this checksum offloading problem:*

features related to TCP chimney offload available on the network card. to access these options, choose the Configure button on the General Tab Of The adapters properties. this will bring up a window similar to what is displayed below. the Advanced tab is where the changes will be made. The retriable options available vary depending on how the vendor implements the driver for Windows. using networ

happened.On a piece of white paper, draw a bunch of gate circuits, and then randomly combine them, slowly, I suddenly found that this circuit is the framework of TSO. I remember helping people fix the routing forwarding last week, but that kind of curing behavior could be too expensive to pass off, after all, now the soft implementation is enough. So only the core transmission network needs this curing of the forwarding, but TSO is the server domain of the first push, server too much, far more

Implementation principle of TCP Segment Offload (TSO), offloadtsoIt was so hot in the morning that I suddenly remembered that someone had talked to me about TSO three weeks ago. I also described the principle of TSO. This principle is also very simple. It is nothing more than segmentation by network card hardware, calculate the checksum to free up the CPU cycle.

At first, the private thought that the checksum is just a simple summation of the results, and later in TCP and UDP see the use of the checksum method is a bit strange-binary anti-code (cyclic carry) summation .　　The cognitive process of human beings is bound to be from simple to complex, to see what this binary inverse code loop summation means. Example with 16

Abbreviated as Tso, TCPSEgmentationOFfloadIs used to reduce the CPU overhead of TCP/IP on fast Networks. TSO breaks down large groups of data sent over a network into smaller segments that pass through all the network elements between the source and destination. this type of offload relies on the network interface controller (NIC) to segment the data and then add the