pinggit
commented
3 years ago quote from Laurent:
I’ll have a look. But this is Contrail vrouter design.
Vrouter has ports named vif0/x On vrouter ports we are pluging some interfaces.
Vif 0/0 is connected to the compute physical bond used to get physical connectivity Vif 0/1 is connected to the vrouter agent “logical interface”. Vrouter agent logical interface is named vhost0. Vif 0/2 is connected to the vrouter agent pkt0 interface. Pkt0 is used to get a copy of any user packet for which the controller need to take a decision (no rule currently known at dataplane level) Vif 0/N are connected to Virtual Machine vNIC of the virtual machines spawn in the cloud infra.
A Virtual machine vNIC has 2 side:
- A frontend, visible inside the virtual macbine. This side is named eth0, eth1, …
- A backend, visible inside the hypervisor OS (OpenStack compute). This side is a tap device, generally named tap xxx. This side is built by VirtIO. The backend side is connected onto vif 0/N (with N > 3, as the previous digits are statically allocated by design)
A machine virtual NIC eth0, has a backend side into the hypervisor OS, the tap device (tap xxx) which is connected to one vrouter port vif 0/n.
This is exactly like in a real world. Tapxxx is just the visible part outside the machine + the cable, used to interconnect a virtual machine NIC onto the first available vrouter port. I hope it clarifies.
If needed, I could add few word in the doc, and a drawing.
we know vif0/0 connect to pNIC, vif0/1 vhost0, vif0/2 pkt0, etc. need some explanation about these mappings and why this design is required.