Re-introducing E1 in OsmoBSC Harald Welte - - PowerPoint PPT Presentation

▶
re introducing e1 in osmobsc
SMART_READER_LITE
LIVE PREVIEW

Re-introducing E1 in OsmoBSC Harald Welte - - PowerPoint PPT Presentation

May 09, 2023 123 likes •220 views

Re-introducing E1 in OsmoBSC Harald Welte <laforge@gnumonks.org> Intro OpenBSC (later OsmoNITB) started with E1 BTS until NITB Split, E1 support remained present even old OsmoBSC (sccplite) never had E1 BTS suport new OsmoBSC also has no

slide-1
SLIDE 1

Re-introducing E1 in OsmoBSC

Harald Welte <laforge@gnumonks.org>

slide-2
SLIDE 2

Intro

OpenBSC (later OsmoNITB) started with E1 BTS until NITB Split, E1 support remained present even old OsmoBSC (sccplite) never had E1 BTS suport new OsmoBSC also has no E1 BTS support let’s change that!

slide-3
SLIDE 3

Classic OsmoNITB with E1-BTS + ext MNCC

e1_input BTS subchan_demux SS0 SS1 SS2 SS3 E1/T1 64k Slots 1 T S trau_decode MNCC OsmoNITB PBX GSM_TCHF_FRAME

Abis/E1 with 16k sub-slots in 64k slots E1 device offers 64k timeslots only 16k sub-channel mux/demux done in software TRAU frames in 16k sub-slots decoded (to FR/EFR codec frames) passed next to MNCC signaling over MNCC socket

slide-4
SLIDE 4

Classic OsmoNITB with E1-BTS + ext MNCC + RTP

e1_input BTS subchan_demux SS0 SS1 SS2 SS3 E1/T1 64k Slots 1 T S trau_decode RTP OsmoNITB PBX RTP

just like previous example, but we generate RTP from TRAU frames MNCC interface is signaling only user voice frames handled via RTP

slide-5
SLIDE 5

Classic OsmoNITB with IP-BTS + ext MNCC + RTP proxy

rtp_sock BTS Abis/IP RTP RTP OsmoNITB PBX RTP

Abis/IP BTS use RTP transport for speech frames OsmoNITB is asked to provide RTP proxy functionality

slide-6
SLIDE 6

Classic OsmoNITB with IP-BTS + ext MNCC + direct RTP

BTS Abis/IP RTP OsmoNITB PBX R T P MNCC

Abis/IP BTS use RTP transport for speech frames OsmoNITB rtp_proxy is disabled RTP data passes directly from BTS to external PBX and vice-versa

slide-7
SLIDE 7

IP-BTS User Plane in post-NITB

When using IP-based BTS like OsmoBTS, this looks like this: RTP to/from the BTS is handled by the BSC-colocated OsmoMGW

slide-8
SLIDE 8

E1-BTS User Plane in post-NITB

When using E1-based BTS, it should look like this: TRAU frames in 16k E1 sub-slots to/from the BTS are handled by the BSC-colocated OsmoMGW OsmoMGW needs real media gateway functionality from E1 sub-slots to RTP E1 driver needs to support single E1 span (line) that

  • pens RSL/OML LAPDm signaling on one TS from OsmoBSC
  • pens TRAU on other TS from OsmoMGW
  • smo-bsc.cfg states which Um TS maps to which E1 TS/SS
  • smo-bsc uses MGCP EP naming scheme like E1/Line1/TS4/SS2@mgw
slide-9
SLIDE 9

EOF

End of File