How Packets Comes to NIC and Host Machine.

How Packets Comes to NIC and Host Machine.

1. Ring Buffer Contains Start and End Address of Buffer in RAM. TX Ring will contain addresses of Buffer in RAM that contains data to be transmitted. RX Ring will contains address of Buffer in RAM where NIC will place data.
   These rings are present in RAM.
2. TX buffer and RX buffer are are in RAM pointed by TX/RX rings.
3. Now Network Card Register has Location of Rings Buffer in RAM .

Now 1 and 2 can be DMA able buffer , they are called DMA TX/RX ring and DMA TX/RX buffer. Now since RX/TX ring must remain throughout they are made as consistent/coherent DMA type of meory. While Buffers are made streaming/Single DMA type of memory

Reference:
https://homerl.github.io/2018/07/12/nic_info/
https://pdfs.semanticscholar.org/18b1/42b7e8d3ea1549b4f53701d97654179b2616.pdf
(

Development and evaluation of a low-cost scalable architecture for network traffic capture and storage for 10Gbps networks)