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Accelerate3g5 -- neels » History » Revision 8

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neels, 03/03/2017 12:05 AM


Accelerate3g5 -- neels

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).

Participants

Details

For various reasons, the previously integrated HLR functionality is currently being split from OsmoNITB, on the neels/vlr branch. UMTS AKA using the Milenage algorithm already works for 2G using that branch, but the sysmocom/iu 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

Work-in-progress is kept on the openbsc.git:neels/iu branch.
When done, this will become the new sysmocom/iu branch.

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.

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

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Updated by neels about 7 years ago · 8 revisions

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