Accelerate3g5 -- neels » History » Revision 7
Revision 6 (neels, 03/03/2017 12:01 AM) → Revision 7/25 (neels, 03/03/2017 12:02 AM)
h1. Accelerate3g5 -- neels {{>toc}} h2. Summary Implement Osmocom 3G support integrated with the new libvlr, so that standard USIMs with full UMTS AKA can be used with the 3G OsmoMSC. This is actually a prerequisite for the accelerate3g5 contestants to be able to use their USIMs with the nano3G (without going into reprogramming it). h3. Participants * Neels (nhofmeyr@sysmocom.de) h2. Details For various reasons, the previously integrated HLR functionality is currently being split from OsmoNITB, on the "neels/vlr":http://git.osmocom.org/openbsc/log/?h=neels/vlr branch. UMTS AKA using the Milenage algorithm already works for 2G using that branch, but the "sysmocom/iu":http://git.osmocom.org/openbsc/log/?h=neels/vlr branch still lacks this capability. Rebase the sysmocom/iu branch onto the neels/vlr branch and resolve all conflicts. Test and verify that 3G works with the sysmoUSIM-SJS1 using Milenage authentication. Related issues are: #1595 #1711 #1593 h2. Journal _2017-02-28_ A first @git rebase@ resulted in numerous conflicts. Starting to resolve... _2017-03-02_ Conflicts have been resolved, but of course the result doesn't compile. Fixing all the errors, and will then need to test+debug, and also review all patches in detail. Rate counters and the logging context are at least incomplete, probably more details and corner cases. _later_ The merged branch compiled. Now the msc_vlr unit tests fail and there are probably still many other errors to resolve. h2. Conclusions I thought that GERAN means exactly A-interface and UTRAN means Iu-interface. But there's also GERAN-over-Iu. RAN is the radio technology, so GERAN _does_ mean 2G BTS, but A and Iu are just the interfaces that these can be controlled with. An MSC may employ an Iu interface to talk to both GERAN and UTRAN radio technology infrastructure. And I thought that UMTS means 3G means UTRAN, but UMTS is "just" the R99 (Release 1999) extension of the protocols. UMTS is used in 3G/UTRAN, yes, but for example UMTS Authentication can be negotiated over 2G networks. I know now because I implemented it. As soon as the MSC says it is R99 capable in the SI3 MSCR bit and the MS is operated with a USIM which "replies" that it is R99 capable in the Classmark IEs sent during Location Updating, CM Service Request and Paging requests, both sides can/will authenticate using UMTS mutual authentication -- another prerequisite of course is that the HLR has UMTS authentication keys stored for this USIM. _todo: have the same UMTS auth over actual UTRAN+Iu_