Hi Richard and list[s], On Tue, Oct 13, 2020 at 05:38:16PM +0100, Richard Haines wrote: > There is in development a 5G version of GTP at [1]. Please note that there is no such thing as "5G version of GTP". The GTP-U (user plane) did not change between 2G, 3G, 4G or even 5G: IT is still the same protocol version (GTPv1-U), which you can see from looking at 3GPP TS 29.281 even in its latest release (Rel 15), which is what the authors of the "gtp5g" github repository reference. What has changed over time is how the protocol is used, and what kind of QoS/classification features are added in order to use different GTP tunnels for different traffic (to the same subscriber / IP address) in order to subject it to different QoS within the 3GPP network. This functionality, by the way, can also be used in 4G networks, and even in 3G/2G networks that follow some of the later releases. The "gtp5g" module hence should in my point not be a separate module, but it should be broken down in incremental feature enhancements to the existing in-kernel GTP user plane module. The netlink interface should also obviously be extended in a backwards-compatible way. My most active kernel years are long gone, but I still think we never have two implementations of the same protocol (GTPv1U in this case) in the Kernel. One could of course also consider to switch to a completely new implementation / rewrite, but only if it is backwards compatible in terms of use cases as well as the netlink interface (and hence existing users of the GTPv1U kernel support). > The other component that seems to be widely used in these systems is > SCTP that I added hooks to a few years ago, [...] indeed, SCTP is extremely heavily used in all cellular systems, from 2G to 4G (with a peak in 4G), but still used on some 5G interfaces. Unfortunately it is the tradition (until today) that none of the industry players that need and use those protocols (GTP, SCTP) seem to be participating in the development and maintenance effort of related implementation. So rather than Nokia, Ericsson or others improving the in-kernel SCTP, their Linux based devices tend to roll their own [userspace] SCTP implementations. Even while in 2020 everybody in "marketing land" speaks about "open source" in the context of cellular/5G, it is not happening. It is only open-washing in order to appear attractive. In reality, anyone in this industry derives a *massive* revenue from their patent royalty collection and they would do anything but release or contribute to code that comes with an explicit or implicit patent license grant. So here we are, in 2020, where every single cellular equipment maker uses Linux, but the most relevant real open source projects in the industry are run by small enthusiast or very small players... Regards, Harald -- - Harald Welte <laforge@xxxxxxxxxxxx> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)
