Intro

we had GSM networks at CCC events since 2008
- Initially using proprietary, E1-attached Siemens BTS and OpenBSC (later OsmoBSC)
we had GSM networks at European Hacker Camps since 2009 (HAR)
we had UMTS (3G) for a few years now, too
- using Osmocom stack with OsmoHNBGW / OsmoMSC / OsmoSGSN

LTE

new network elements with new acronyms

LTE

new protocols on all layers of all interfaces
- S1AP between eNodeB and MME
- GTPv2C between MME and SGW and SGW and PGW
- DIAMETER between everyone and HSS

FOSS LTE software

srsLTE for eNodeB and UE
- main focus on UE; eNodeB features somewhat limited
- super simplistic srsEPC suitable for only the scarcest of use cases
OpenAirInterface
- obscure code base; difficult to build; "
- very research oriented
- RAN part under non-free, non-opensource but source available license
nextepc

nextepc

Implements all key LTE network (EPC) elements
- MME
- SGW
- PGW
- HSS
- PCRF

interfacing with Osmocom 2G/3G core

shared subscriber (and key) database
- LTE: HSS, speaking DIAMETER
- 2G/3G: HLR, speaking MAP (Osmocom:GSUP)
We need a so-called 'inter-working function (IWF)
- translate from DIAMETER to GSUP and vice-versa

osmo_dia2gsup

Best FOSS DIAMETER support contained in Erlang/OTP
Fairwaves contributed GSUP protocol codec in Erlang
I wrote a translator for the two minimal procedures
- AuthInfo (Obtain authentication tuples)
- UpdateLocation (registration)

Network layout

EOF

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