[PATCH v2 1/2] net/bonding: introduce direct link bonding mode

[Stephen Hemminger]

On Wed, 10 Jul 2024 07:16:58 +0200
Kamil Vojanec <vojanec at cesnet.cz> wrote:

> Hi,
> 
> > I don't find the 'direct' mode in latest Linux. Do you have a plan to 
> > do this in Linux  
> No, I was not planning on any Linux kernel contributions.
> > IIUC, the 'direct' mode just to let the packets from one port send out 
> > at the same port, right?
> > If it is, why do you introduce this new mode? It doesn't seem to have 
> > anything to do with bonding.   
> Indeed, the base functionality is to forward packets to the same port 
> they were received on. The main use-case is to allow applications use 
> one aggregated (bonding) port ensure that packet forwarding is always 
> the same.
> 
> I find it a lot simpler to use a bonding port whenever I have an 
> application that uses multiple ports. It means I don't have to 
> configure, start and stop all the ports; the bonding PMD is a perfect 
> abstraction for that.
> 
> Kamil

There is overlap between bonding and bridging especially when used as leaf.
This use case sounds like a new driver, rather than dog piling more features
on already complex bridge device. Maybe a new simple bridge PMD would
be more appropriate.

Alternatively, the user transmit policy callback could be an option?