Osmocom Libraries » libosmo-sccp + libosmo-sigtran

M3UA has the notion of an (entirely optional) "Network Appearance" IE. We don't support it at all

The spec says:

Network Appearance - The Network Appearance is a M3UA local reference shared by SG and AS (typically an integer) that, together with an Signaling Point Code, uniquely identifies an SS7 node by indicating the specific SS7 network to which it belongs. It can be used to distinguish between signalling traffic associated with different networks being sent between the SG and the ASP over a common SCTP association. An example scenario is where an SG appears as an element in multiple separate national SS7 networks and the same Signaling Point Code value may be reused in different networks.

Supporting this properly in libosmo-sigtran is likely non-trivial, as it means that everywhere where right now only the point code is considered, we need to consider point code + network appearance. This affects not only routing decisions, but it also affects things like peer addresses of SCCP connections.