From 98895caa2d4334fa60311d0ffe36b219028622d9 Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Sat, 14 Apr 2018 00:15:38 +0200 Subject: osmocon2018: reintroducing E1 --- .../osmodevcon2018-reintroducing_e1.html | 4062 ++++++++++++++++++++ 1 file changed, 4062 insertions(+) create mode 100644 2018/osmodevcon2018-reintroducing_e1/osmodevcon2018-reintroducing_e1.html (limited to '2018/osmodevcon2018-reintroducing_e1/osmodevcon2018-reintroducing_e1.html') diff --git a/2018/osmodevcon2018-reintroducing_e1/osmodevcon2018-reintroducing_e1.html b/2018/osmodevcon2018-reintroducing_e1/osmodevcon2018-reintroducing_e1.html new file mode 100644 index 0000000..e41b1d6 --- /dev/null +++ b/2018/osmodevcon2018-reintroducing_e1/osmodevcon2018-reintroducing_e1.html @@ -0,0 +1,4062 @@ + + + + +Re-introducing E1 in OsmoBSC + + + + + + + + +
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Intro

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+
    +
  • + +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! + +
    • +
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+

Classic OsmoNITB with E1-BTS + ext MNCC

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+osmo-userplane1_e1_mncc.svg +
+
+
    +
  • + +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 + +
    • +
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+

Classic OsmoNITB with E1-BTS + ext MNCC + RTP

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+osmo-userplane2-e1_rtp.svg +
+
+
    +
  • + +just like previous example, but we generate RTP from TRAU frames + +
    • +
  • + +MNCC interface is signaling only + +
    • +
  • + +user voice frames handled via RTP + +
    • +
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+

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

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+osmo-userplane3-rtp_proxy.svg +
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+
    +
  • + +Abis/IP BTS use RTP transport for speech frames + +
    • +
  • + +OsmoNITB is asked to provide RTP proxy functionality + +
    • +
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Classic OsmoNITB with IP-BTS + ext MNCC + direct RTP

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+osmo-userplane4-rtp_direct.svg +
+
+
    +
  • + +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 + +
    • +
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+

IP-BTS User Plane in post-NITB

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When using IP-based BTS like OsmoBTS, this looks like this:

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+osmodevcon2018-reintroducing_e1__1.png +
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+
    +
  • + +RTP to/from the BTS is handled by the BSC-colocated OsmoMGW + +
    • +
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E1-BTS User Plane in post-NITB

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When using E1-based BTS, it should look like this:

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+
+osmodevcon2018-reintroducing_e1__2.png +
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+
    +
  • + +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 + +
      +
    • + +opens RSL/OML LAPDm signaling on one TS from OsmoBSC + +
      • +
    • + +opens TRAU on other TS from OsmoMGW + +
      • +
    +
    • +
  • + +osmo-bsc.cfg states which Um TS maps to which E1 TS/SS + +
    • +
  • + +osmo-bsc uses MGCP EP naming scheme like E1/Line1/TS4/SS2@mgw + +
    • +
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+

EOF

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End of File

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