Adding priority for EMLPP service in paging type 1

[Snehasish Kar]

Snehasish Kar has shared a OneDrive file with you. To view it, click the link below.


<https://1drv.ms/u/s!Ar2IfAyw5vH1gQsxLkqbowdVcPya>
[https://r1.res.office365.com/owa/prem/images/dc-generic_20.png]<https://1drv.ms/u/s!Ar2IfAyw5vH1gQsxLkqbowdVcPya>

emlpp_test.pcapng<https://1drv.ms/u/s!Ar2IfAyw5vH1gQsxLkqbowdVcPya>



Hello Harald

I have updated the abis_rsl.c. But I have a small confusion, please correct me, the IE for EMLPP is of 2 Bytes out of which the second octet contains only last 3 bits as priority and msgb_tv_put allows to set only one octet, thus on setting anything above 5 it shows call_priority as 0 and anything less than that as 4. Please let me know where I am going wrong.Below is the patch and pcap has been attached.

diff --git a/openbsc/src/libbsc/abis_rsl.c b/openbsc/src/libbsc/abis_rsl.c
index 5a508b207..5b45cd497 100644
--- a/openbsc/src/libbsc/abis_rsl.c
+++ b/openbsc/src/libbsc/abis_rsl.c
@@ -1034,6 +1034,8 @@ int rsl_paging_cmd(struct gsm_bts *bts, uint8_t paging_group, uint8_t len,
        if (bts->type == GSM_BTS_TYPE_RBS2000 && is_gprs)
                msgb_tv_put(msg, RSL_IE_ERIC_PACKET_PAG_IND, 0);

+       msgb_tv_put(msg, RSL_IE_EMLPP_PRIO, 0x00);
+
        msg->dst = bts->c0->rsl_link;

Best Regards
Snehasish

________________________________
From: Harald Welte <laforge at gnumonks.org>
Sent: Thursday, December 27, 2018 2:28 AM
To: Snehasish Kar
Cc: openbsc at lists.osmocom.org
Subject: Re: Adding priority for EMLPP service in paging type 1

Hi Snehasish,

On Wed, Dec 26, 2018 at 02:13:38PM +0000, Snehasish Kar wrote:
> Please find the updated patches:

Thanks, there were no requested related pcap traces, though.

I think you are making the wrong assumption that you can simply add a byte
to the RSL message which then magically appears on the Um interface.  Instead,
you need to study how eMLPP is actually implemented over Abis. There's an additional
information element that needs to be added to the RSL PAGING COMMAND, see Section
8.5.5 of 3GPP TS 48.058.  The IE is of type TV, so you need to msgb_put_tv(...)
to add it.

Furthermore, you will need to teach OsmoBTS (assuming you are using OsmoBTS) to
interpret that additional IE and then construct the air interface paging rest
octets from it.

Please also notice that openbsc.git is no longer maintained anymore and it is
strongly suggested you switch to the new "split NITB" architecture consisting of
osmo-bsc.git + osmo-msc.git + osmo-hlr.git.

We're very much looking forward to receiving your patches contributing eMLPP
support to the Osmocom stack.

Regards,
        Harald

--
- Harald Welte <laforge at gnumonks.org>           http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osmocom.org/pipermail/openbsc/attachments/20181229/ad9522fe/attachment.htm>