Hi Jonas, On Fri, Feb 03, 2017 at 10:12:31AM +0100, Jonas Bonn wrote: > The GTP-tunnel driver is explicitly GGSN-side as it searches for PDP > contexts based on the incoming packets _destination_ address. If we > want to write an SGSN, then we want to be idenityfing PDP contexts > based on _source_ address. > > This patch adds a "flags" argument at GTP-link creation time to specify > whether we are on the GGSN or SGSN side of the tunnel; this flag is then > used to determine which part of the IP packet to use in determining > the PDP context.
So far the implementation that I saw in osmocom relies on userspace code to tunnel data from ME to the SSGN/SGW running on the base station. The data we get from GGSN -> SGSN needs to be places into a SN-PDU (via SNDCP) when sending it to the BTS, right? So I wonder how this can be useful given that we would need to see real IP packets coming to the SSGN that we tunnel into GTP. Thanks!
