Fix Dl EGPRS data blocks being generated occasionally on GPRS TBFs

Under some circumstances, it could happen that a DL TBF is created as a
GPRS TBF due to not yet having enough information of the MS, and only
after the TBF is created the PCU gains that information and upgrades the
MS mode to "EGPRS". Hence, there's the possibility to run into a
situation where a GPRS TBF is attached to a EGPRS MS.

It may also happen sometimes that despite the TBF and the MS be EGPRS,
there's need to further limit the DL MCS to use, eg. MCS1-4 (GMSK).

As a result, when asking for the current DL (M)CS to use, we must tell
the MS which kind of limitations we want to apply. The later reasoning
was already implemented when GPRS+EGPRS multiplexing was added, but the
former was not being checked. Hence, by further spreading through the
call stack the "req_kind_mode" we match both cases.

Related: OS#4973
Change-Id: Ic0276ce045660713129f0c72f1158a3321c5977f
6 files changed
tree: 2c932decf47cfaca1212b2f6d4698c6640095b6c
  1. contrib/
  2. debian/
  3. doc/
  4. include/
  5. src/
  6. tests/
  7. .gitignore
  8. .gitreview
  9. configure.ac
  10. COPYING
  11. git-version-gen
  12. Makefile.am
  13. osmoappdesc.py
  14. README.md
  15. TODO
  16. TODO-RELEASE
README.md

osmo-pcu - Osmocom Packet Control Unit

This repository contains a C/C++-language implementation of a GPRS Packet Control Unit, as specified by ETSI/3GPP. It is part of the Osmocom Open Source Mobile Communications project.

The Packet Control Unit is terminating the Layer 2 (RLC/MAC) of the GPRS radio interface and adapting it to the Gb Interface (BSSGP+NS Protocol) towards the SGSN.

The PCU interfaces with the physical layer of the radio interface. OsmoPCU is typically used co-located with the BTS, specifically OsmoBTS. For legacy BTSs that run proprietary sotware without an interface to OsmoPCU, you may also co-locate it with the BSC, specifically OsmoBSC

Homepage

The official homepage of the project is https://osmocom.org/projects/osmopcu/wiki/OsmoPCU

GIT Repository

You can clone from the official osmo-pcu.git repository using

git clone git://git.osmocom.org/osmo-pcu.git

There is a cgit interface at http://git.osmocom.org/osmo-pcu/

Documentation

We provide a user manual as well as a vty reference manual

Please note that a lot of the PCU configuration actually happens inside the BSC, which passes this configuration via A-bis OML to the BTS, which then in turn passes it via the PCU socket into OsmoPCU.

Mailing List

Discussions related to osmo-pcu are happening on the osmocom-net-gprs@lists.osmocom.org mailing list, please see https://lists.osmocom.org/mailman/listinfo/osmocom-net-gprs for subscription options and the list archive.

Please observe the Osmocom Mailing List Rules when posting.

Contributing

Our coding standards are described at https://osmocom.org/projects/cellular-infrastructure/wiki/Coding_standards

We us a gerrit based patch submission/review process for managing contributions. Please see https://osmocom.org/projects/cellular-infrastructure/wiki/Gerrit for more details

The current patch queue for osmo-pcu can be seen at https://gerrit.osmocom.org/#/q/project:osmo-pcu+status:open

Current limitations

  • No PFC support
  • No fixed allocation support (was removed from 3GPP Rel >= 5 anyway)
  • No extended dynamic allocation support
  • No unacknowledged mode operation
  • Only single slot assignment on uplink direction
  • No half-duplex class support (only semi-duplex)
  • No TA loop
  • No power loop
  • Multi-BTS support not tested