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Bruce Fitzsimons

Hi Martin,

Have you seen any more detail on NSNs VoLTE solution that they've been crowing about? There is little available information, but it looks like they turn their 3G MSC into an odd SIP SBC, possibly one that translates SIP REGISTERs to MAP UPDATE_LOCATIONs (et al).

This would require a SIP client on the handset and a dedicated APN (I assume) but it seemingly overlooks any CSLTE handoffs, although I guess seamless HSPALTE is possible (right?) so the call could transition transports without needing to be aware.

An interesting alternative anyway.


Hi Bruce,

No, I haven't seen any more details but I guess there must be a reason why NSN is so tight lipped about their solution. In my opinion proprietary solutions and solutions that can't hand over to CS during a call are not the answer to the LTE voice problem.

From a technology point of view I also think they've implemented some kind of SIP support in their MSC but it's an opinion, I don't have facts to back it up.


typepad@sixapart.com wrote:

Gabriel Brown

@Bruce -- It said to use SR-VCC to handover. Ultimately, the MSC-Server looks like an applications server from an IMS point of view. Lots of pros and cons, of course.

Seperately, Volga appears to building support outside T-Mobile. Lots of people seem to like the solution, but aren't ready to commit one way or the other yet. Fair bit of political maneuvering involved from what I understand.


Hi Gabriel,

Interesting side note: SR-VCC was first specified for IMS. Now it's also part of VoLGA and potential also of the proprietary NSN solution. Quite a versatile functionality.


typepad@sixapart.com wrote:

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