open5gs/lib/gtp
Pau Espin 3d693da73e [MME] Gn: Introduce initial support for 4G->2G cell reselection
In an Inter-RAT setup a UE could perform a RAU coming from a 4G network.
In that case the UE/MS is unknown to the SGSN and it should request the
SGSN context (MM, PDP) from the MME. This is done through the following
GTPv1C message exchange on the Gn interface of SGSN and MME:
SGSN -> MME: SGSN Context Request
SGSN <- MME: SGSN Context Response
SGSN -> MME: SGSN Context Acknowledge

This commit doesn't aim to be a complete implementation of the mentioned
procedure, since it's quite a complex one, with lots of fields and logic
required. This so far only implements in general the minimally
successful case by filling as much as possible the required set of
fields.
This will allow for a base onto which do incremental improvements and
fixes while testing against UEs and SGSNs (such as osmo-sgsn, which
doesn't yet support this procedure but will potentially earn it soon).

This commit doesn't implement the reverse direction, aka UE issuing cell
reselection 2G->4G. Initial support for this scenario will hopefully be
added soon as a follow-up patch, similar to this one.

Related: https://osmocom.org/issues/6294
2023-12-23 09:56:55 +09:00
..
v1 [MME] Gn: Introduce initial support for 4G->2G cell reselection 2023-12-23 09:56:55 +09:00
v2 [GTPU] Fixed Stack-Buffer-Overflow in GTPU (#2609) 2023-09-15 07:17:04 +09:00
context.c [SEPP] Initial Update for 5G Roaming (#2739) 2023-11-19 19:34:51 +09:00
context.h Initial metrics support based on Prometheus (#1571) 2022-06-08 05:51:02 +09:00
meson.build [NRF] Fixed library load error 2022-08-26 10:57:11 +09:00
ogs-gtp.h [NRF] Fixed library load error 2022-08-26 10:57:11 +09:00
path.c [CORE] Improve logging error in ogs_gtp_sendto() (#1591) 2022-06-09 23:32:11 +09:00
path.h Introduce Gn interface (GTPv1C) Support to PGW (#1351) 2022-02-18 22:23:45 +09:00
util.c [GTPU] Fixed Stack-Buffer-Overflow in GTPU (#2609) 2023-09-15 07:17:04 +09:00
util.h [GTPU] Fixed PDCP SN handling (#2584, #2477) 2023-09-10 22:37:42 +09:00
xact.c lib/gtp: Fix xact logic for gtp1 messages with intermediate stage 2023-12-22 06:04:18 +09:00
xact.h [PFCP/GTP] SEID/TEID Randomness (#1303) 2023-04-16 12:30:36 +09:00