On Wed, 2016-11-30 at 17:55 +0100, Andrew Lunn wrote: > > This is an embedded system with several boards in a subrack. > > Each board has eth I/F connected to a switch to communicate with each other. > > One of the board will also house the actual switch device and manage the > > switch. > > Then the normal app just communicates over the physical eth I/F like any > > other board > > in the system. There is a "manage switch app" which brings the switch up > > and partition > > phys VLANs etc. (each phys I/F would be a a separate domain so no loop) > > So you are planning on throwing away the "manage switch app", and just > use standard linux networking commands? That is what switchdev is all > about really, throwing away the vendor SDK for the switch, making a > switch just a bunch on interfaces on the host which you manage as > normal interfaces.
Something like that. I need to run routing protocols on the switch I/Fs and egress pkgs on selected switch I/Fs bypassing ARP, just like DSA does with its vendor tags. > > > I guess I could skip the phys I/F and have the switch app create a virtual > > eth0 I/F over PCIe > > No need to create this interface. It will exist if you go the > switchdev route. > > > > > And switchdev can do all this over PCIe instead? Can you have a > > > > switch tree in switchdev too? > > > > > > Mellonex says so, but i don't think they have actually implemented it. > > > > Not impl. any of DSAs features? What can you do with a Mellonex switch then? > > They don't have a tree of switches, as far as i know. Just a single > switch. But DSA does support a tree of switches, that is what the D in > DSA means, distributed. And there are a couple of boards which have 2 > to 4 switches in a tree. We might have a tree as well so now I really wonder: Given we write a proper switchdev driver, can it support switchtrees without touching switchdev infra structure? If not I guess we will attach a physical eth I/F to the switch and use both DSA and switchdev to support both trees and HW offload. > > I think this is partially down to market segments. Mellonex market is > top of rack switches. High port count, very high bandwidth. DSA is > more wireless access points, set top boxes, generally up to 7 ports of > 1Gbps and a few custom embedded products which need more ports, so > build a tree of switches. We have on an existing board with a BCM ROBO switch with lots of ports(>24), managed over SPI. Looking at BCM DSA tag code it looks like it only supports some 8 ports or so. I still have to find out if this is a limitation in BCM tagging protocol or if just not impl. in DSA yet.
