ring and packet buffer

[pinggit]

ch2 page 29:

this clearly shows, 2 different objects exist in host AND NIC:

1. pointers (ring, array of descriptors/pointers), which points to the address of real packets
2. the buffer which stores the real packet data

in NIC: it is called queue (pointers), and FIFO (buffer for data)

in host: it is called ring(array of pointers), and mbuf(buffer for data)

[ldurandadomia]

Yes. But it is more to underline we have to transfer packets from 2 distinct environments:

• NIC
• HOST Rings are memory structures used in VIRTIO and DPDK. They are "circular queue". For NIC, queue topology is unspecified. With VDPA, NC are also using rings.

queue and buffers (FIFO) are generic terms. ring and mbuf are the same but in DPDK context.

[pinggit]

this is an important clarification I believe, when you want to pursue the conceptually accuracy. normally the term "queue" means the buffer for real data. At least in router docs it is normally that. but in this specific diagram it really means the pointers (addr of mem) pointing to the real buffers.

on the other hand, in some other context of the book, I believe we also refer "queue" as the data buffer. I hope this won't be a problem for readers.