Marcel Holtmann <marcel@xxxxxxxxxxxx> writes: > I do not wanna run DHCP at all on these links. I assume we have a > command that tells us what IP and DNS are used and then we just set it. Yes, the QMI_WDS command 0x002d "GET_RUNTIME_SETTINGS" can be used instead of DHCP. It will report all IP settings (inlcuding the unecessary netmask and gateway) as well as profile, APN and QoS parameters > Running DHCP is as stupid as using PPP for communication with the modem. I see your point, but it has the advantage that it fits nicely into any existing IP configuration tools. And the Windows driver does use it as well. > Actually DHCP and an Ethernet card has the inherent disadvantage that > you need a netmask, The raw IP mode does not change this. It is still a LAN emulation. Like it or not. > and also have to deal with ARP. No, that's not necessary. Setting the IFF_NOARP flag avoids it. > Why would you do that > if your device is not an Ethernet card. Essentially you are blocking > more than the one needed IP address and forcing extra overhead in just > getting your packets over the network. The raw IP mode does not change how addresses are assigned *to* the device. So the address usage is the same. A subnet mask and a gateway address within the same subnet is always provided. I guess this is due to some 3GPP address assignment protocol. > The over the air links are IP and the kernel just exposing a > Point-to-point network interface is perfectly fine. It can like any > other device you create with TUN/TAP for example. It does not matter > what type it is as long as you make it Point-to-point. I don't think I can make it a true point to point in the sense that only two addresses are used. The address assignment is part of some device/network communication which I cannot influence AFAIK. So, there is no real benefit wrt addressing. I can of course make a device which ignores the netmask (in fact, using NOARP already does), but it does not improve anything. Bjørn -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
