| commit | 37c2f84d53d1a8cf80f9a5088fd0fe1f994c4358 | [log] [tgz] |
|---|---|---|
| author | Pau Espin Pedrol <pespin@sysmocom.de> | Tue Jun 27 18:02:33 2023 +0200 |
| committer | Pau Espin Pedrol <pespin@sysmocom.de> | Thu Jun 29 14:53:09 2023 +0200 |
| tree | 49dcbfb2435bc60aa4572a7e5274fb6733cbca6c | |
| parent | 11627ffaae4975f03e7290138cd93737b29d6181 [diff] |
Reestore last LLC frames never completely acked when freeing DL TBF Scenario: A DL TBF is assigned over PCH (CCCH) and we start transmitting DL data blocks blindly after X2002, but at the same time the MS start packet-access-procedure to request an UL TBF. Right now osmo-pcu correctly detects the MS is available in PDCH and re-assigns a DL TBF using PACCH, but the LLC frames it transmitted in the old PCH-assigned DL TBF get lost when that older TBF is freed (because the DL blocks were removed from the GprsMs llc_queue). This issue is now more frequent since X2002 timer was added recently to delay starting requesting USF for a UL TBF, hence the contention resolution in general takes more time and hence the PACCH assignment of the DL TBF takes more time too, so more DL data blocks are transmitted to the DL TBF assigned over PCH during that time. This patch improves the situation to at least recover the DL blocks transmitted if the DL TBF is freed (due to MS merge trigger by scenario mentioned above), where no DL ACK/NACK was ever received by the MS. Ideal solution would be to have complete tracking of which LLC PDUs from the llc_queues were completely ACKed at RLC/MAC level, but that really requires a lot of work and major refactoring, which are left as a future improvement. Change-Id: I9be4035fb2cf2b3ee56e91dcc12cc8c24028b4aa
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
The official homepage of the project is https://osmocom.org/projects/osmopcu/wiki/OsmoPCU
You can clone from the official osmo-pcu.git repository using
git clone https://gitea.osmocom.org/cellular-infrastructure/osmo-pcu
There is a web interface at https://gitea.osmocom.org/cellular-infrastructure/osmo-pcu
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.
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.
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