Hi Harald,
With a limited set of resources available, I would
always rather spend the resources on making the BSC and BSSAP/BSSMAP more complete, than
spend time on a new M3UA implementation - which doesn't add >new functionality, as
an existing external signalling gateway could do the SUA-M3UA translation with no R&D
involved.
We went through the OsmoSS7 Erlang code base and the webpage "
https://projects.osmocom.org/news/30"quot;, we see no activity done on osmo-ss7 for 3
years.
Considering the use of osmo-ss7 as the signaling gateway for SUA to SCCP/M3UA translation,
we have following concerns:
a. Is osmo-ss7 compliant to latest specifications of SCCP and M3UA?
b. Does osmo-ss7 implement the complete functionality of the signaling gateway.
c. Is osmo-ss7 inter-op tested with 3rd party 3GPP compliant MSC and osmo-BSC.
d. After upgrading SUA and the BSSAP, can the osmo-bsc be tested with 3rd party MSC by
using the osmo-ss7 as signaling gateway? Do you see some changes on OsmoSS7 codebase?
e. If osmo-ss7 does the complete functionality of the signaling gateway that is
translation from SUA to SCCP/M3UA then why to upgrade the SCCP and implement M3UA in
osmo-bsc even in future.
Regards,
Bindhu
-----Original Message-----
From: OpenBSC [mailto:openbsc-bounces@lists.osmocom.org] On Behalf Of Harald Welte
Sent: Tuesday, March 15, 2016 7:28 PM
To: Bindhu Anjaneya <Bindhu.Anjaneya(a)radisys.com>
Cc: openbsc(a)lists.osmocom.org
Subject: Re: Support of AoverIP (AOIP) in osmo-bsc
Hi Bindhu,
On Tue, Mar 15, 2016 at 11:33:01AM +0000, Bindhu Anjaneya wrote:
Though the above approach is the simplest way, this
implementation
will not be in compliance with 3GPP specification, this would also
introduce a hop between BSC and MSC on the A-Interface.
I don't think the extra hop would be a problem. It reduces the implementation
complexity and a SUA-capable BSC is an initial, functional implementation that could
already be deployed. Real M3UA support could be a second, incremental step at a later
point.
We prefer to do development in smaller, more easily digestable chunks rather than having a
too large scope for a task from the beginnign.
Also, on the BSSAP/BSSMAP level, the A interface exposed by OsmoBSC is also limited in
many ways. It only implements Intra-BSC hand-overs, and no Inter-BSC hand-overs at that
point.
With a limited set of resources available, I would always rather spend the resources on
making the BSC and BSSAP/BSSMAP more complete, than spend time on a new M3UA
implementation - which doesn't add new functionality, as an existing external
signalling gateway could do the SUA-M3UA translation with no R&D involved.
So my suggestion is for Osmo-bsc to be 3GPP
compliance, the SIGTRAN
stack BSSAP/SCCP/M3UA/SCTP/IP need to be implemented in Osmo-bsc.
To achieve this:-
Existing SCCP - need to be upgraded if needed
It will definitely need to be, as there is no code for connection-oriented SCCP at all.
libosmo-sccp only contans code for encoding/decoding some SCCP frames.
M3UA - need to be developed may be as a separate
library
should be part of libosmo-netif, as is the current SUA code.
The applications should all simply use the sccp-user-sap that we already offer and use
from the IuCS/IuPS side, and not worry about the underlying protocol stack. This way we
ensure that later on, any added M3UA or other SIGTRAN protocol stack will not require
modifications to the applications on top.
We can introduce a compile time flag if we need to
differentiate
between the support for SCCP/M3UA and SUA.
We don't like that. When supporting multiple protocol stacks, we introduce one
common/shared interface abstraction and we switch at run-time based on configuration. For
example, osmo-gbproxy supports NS-over-IP as well as NS-over-FR-over-GRE as two
alternative stacks.
--
- Harald Welte <laforge(a)gnumonks.org>
http://laforge.gnumonks.org/
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