Hi OpenBSC,
My company is working on integrating some BTS (Nokia Flexi ESMB) with Nokia packet Abis with OsmoBSC.
The Nokia packet Abis seems to be Nokia OML/RSL over SCTP/IUA (RFC 3057).
To get started, we have built a little stub that takes the incoming SCTP/IUA connection and carries out ASP_UP/ASP_ACTIVE handshake. After this handshake is complete, we see OML coming in from the BTS.
It seems that this OML is in a form that would be understood by "bts_nokia_site.c". So now we would like to continue the experiment by feeding the OML/RSL into a BTS configured in OsmoBSC as type "nokia_site".
Now the questions: 1. Is it possible to configure a BTS of type "nokia_site" to run Abis over a unix domain socket ? 2. Is there a better way to prototype this integration ?
PS: PCAP trace available on request
Best Regards, Michael Andersen
On Wed, Sep 12, 2018 at 07:16:00PM +0200, Michael Andersen wrote:
Hi OpenBSC,
My company is working on integrating some BTS (Nokia Flexi ESMB) with Nokia packet Abis with OsmoBSC.
The Nokia packet Abis seems to be Nokia OML/RSL over SCTP/IUA (RFC 3057).
To get started, we have built a little stub that takes the incoming SCTP/IUA connection and carries out ASP_UP/ASP_ACTIVE handshake. After this handshake is complete, we see OML coming in from the BTS.
Short of teaching osmo-bsc to listen for and handshake SCTP/IUA ... Maybe you could just open Abis/IP connections from your stub to osmo-bsc and feed OML and RSL through those? e.g. using the libosmo-abis client, like osmo-bts does?
Let me plug here: In case you would like to have more concrete and timely assistance than a public mailing list can provide in developers' free time, maybe it would help you to book professional support from an Osmocom affiliated company? (My employer comes to mind.) It's not mandatory, of course, but especially for professional use of Osmocom it would be good to support the community ecosystem. Booking support hours (that helps pay developers' wages) is just one possibility, more ways would be to contribute patches / documentation / ... As you see fit.
~N
Hi Michael,
On Wed, Sep 12, 2018 at 07:16:00PM +0200, Michael Andersen wrote:
My company is working on integrating some BTS (Nokia Flexi ESMB) with Nokia packet Abis with OsmoBSC.
this sounds very exciting! I'm really happy to read that somebody is working on supporting some other BTS models / dialects.
The Nokia packet Abis seems to be Nokia OML/RSL over SCTP/IUA (RFC 3057).
Interesting. Do you have protocol traces from a working setup with the Nokia BSC?
My usual approach for implementing Abis protocol dialects in all of the Osmocom history has been the following process:
* obtain as many protocol traces as possible (sometimes only 1 or 2) from a working setup * try to find vendor documentation on the Abis specifics (often not available) * try to see if there are protocol analyzers that can decode the vendor specific dialects (Nethawk, MA-10, Tektronix, ...) * implement a wireshark dissector at least for those bits of the protocol that are understood/known/standard * try to re-implement the protocol from the Osmocom side
To get started, we have built a little stub that takes the incoming SCTP/IUA connection and carries out ASP_UP/ASP_ACTIVE handshake. After this handshake is complete, we see OML coming in from the BTS.
Great! I hope you have seen libosmo-sigtran. It already implements SUA and M3UA, and a lot of the infrastructure and the state machines would also workfor M2UA, M2PA, and likely also for IUA.
The next step then would be to think about how to use this new Abis within the context of libosmo-abis, which currently only deals with T1/E1 and IPA/Osmo-stylae Abis/IP.
It seems that this OML is in a form that would be understood by "bts_nokia_site.c". So now we would like to continue the experiment by feeding the OML/RSL into a BTS configured in OsmoBSC as type "nokia_site".
great!
- Is it possible to configure a BTS of type "nokia_site" to run Abis over a
unix domain socket ?
The unixsocket.c code in libosmoabis should be rather generic. I'm not sure anyone has tried to use it with Nokia BTS model so far, but it *should* work.
- Is there a better way to prototype this integration ?
See my above thoughts.
Whatever comes out of this and however far you get, I strongly suggest that you publish all findings for the benefit of the wider community. Thanks!
Regards, Harald
Hi Harald,
The Nokia packet Abis seems to be Nokia OML/RSL over SCTP/IUA (RFC 3057).
Interesting. Do you have protocol traces from a working setup with the
Nokia
BSC?
I have enclosed the trace of the handshake experiment. This is the trace that ends with receiving the OML wrapped in SCTP/IUA.
We are working on getting our hands on a trace from a working setup.
- Is it possible to configure a BTS of type "nokia_site" to run Abis
over a
unix domain socket ?
The unixsocket.c code in libosmoabis should be rather generic. I'm not sure anyone has tried to use it with Nokia BTS model so far, but it
*should* work.
We will try something like this and see if that brings us to a new milestone.
BR, Michael A
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Harald Welte -
Michael Andersen -
Neels Hofmeyr