On Fri, 15 Jan 2021 15:39:06 +0100 Jiri Pirko wrote: > >I'm not a SFP experts so maybe someone will correct me but AFAIU > >the QSFP (for optics) is the same regardless of breakout. It's the > >passive optical strands that are either bundled or not. So there is > >no way for the system to detect the cable type (AFAIK). > > For SFP module, you are able to detect those.
Not sure you understand what I'm saying. Maybe you're thinking about DACs? This is a optical cable for breakout: https://www.fs.com/products/68048.html There is no electronics in it to "detect" things AFAIU. Same QSFP can be used with this cable or a non-breakout. > >Or to put it differently IMO the netdev should be provisioned if the > >system has a port into which user can plug in a cable. When there is > > Not really. For slit cables, the ports are provisioned not matter which > cable is connected, slitter 1->2/1->4 or 1->1 cable. > > > >a line card-sized hole in the chassis, I'd be surprised to see ports. > > > >That said I never worked with real world routers so maybe that's what > >they do. Maybe some with a Cisco router in the basement can tell us? :) > > The need for provision/pre-configure splitter/linecard is that the > ports/netdevices do not disapper/reappear when you replace > splitter/linecard. Consider a faulty linecard with one port burned. You > just want to replace it with new one. And in that case, you really don't > want kernel to remove netdevices and possibly mess up routing for > example. Having a single burned port sounds like a relatively rare scenario. Reconfiguring routing is not the end of the world. > >If the device really needs this configuration / can't detect things > >automatically, then we gotta do something like what you have. > >The only question is do we still want to call it a line card. > >Sounds more like a front panel module. At Netronome we called > >those phymods. > > Sure, the name is up to the discussion. We call it "linecard" > internally. I don't care about the name. Yeah, let's call it something more appropriate to indicate its breakout/retimer/gearbox nature, and we'll be good :)
