Project

General

Profile

OsmoPCU » History » Version 25

laforge, 05/11/2018 11:03 AM

1 1 laforge
h1. osmo-pcu
2 16 zecke2
3 17 laforge
{{>toc}}
4 16 zecke2
5 3 laforge
A PCU (Packet Control Unit) is one of the two GPRS elements in the BSS.  It implements the RLC and MAC layers of the GPRS
6 1 laforge
Um (radio) interface on the MS-facing side, as well as the Gb Interface (NS,BSSGP) on the SGSN-facing side.
7
8 3 laforge
osmo-pcu is the Osmocom implementation of this PCU functionality.
9 1 laforge
10 18 laforge
It implements a custom L1 interface that can be used with [[OsmoBTS:]] (specifically its
11 16 zecke2
"sysmoBTS":http://www.sysmocom.de/products/sysmobts back-end), and also with
12 18 laforge
[[OsmoTRX:]].
13 3 laforge
14 1 laforge
Towards the SGSN, the BSSGP and NS protocols are implemented over UDP/IP, sometimes called "NS over IP". 
15 19 laforge
It has been tested with [[OsmoSGSN:]] as well as an Ericsson SGSN so far.
16 1 laforge
17 13 laforge
osmo-pcu is now considered stable and already performing useful service for a number of users, but as one
18 1 laforge
of the more recent additions to the Osmocom family, there still is plenty of area for improvement.
19 14 jerlbeck
20 23 laforge
h2. Position in a typical Osmocom network
21
22
{{graphviz_link()
23
digraph G {
24
    rankdir = LR;
25
    OsmoBTS -> OsmoBSC [label="Abis/IP"];
26
    OsmoBSC -> OsmoMSC [label="3GPP AoIP"];
27
    OsmoBTS -> OsmoPCU [label="pcu_sock"];
28
    OsmoPCU -> OsmoSGSN [label="Gb/IP"];
29
    OsmoMSC -> OsmoHLR [label="GSUP"];
30
    OsmoSGSN -> OsmoHLR [label="GSUP"];
31
    OsmoSGSN -> OsmoGGSN [label="Gp"];
32
    OsmoGGSN -> Internet [label="Gi"];
33
    OsmoPCU [color=red];
34
}
35
}}
36
37
38 17 laforge
h2. Manuals
39 11 laforge
40 17 laforge
* User Manual: http://ftp.osmocom.org/docs/latest/osmopcu-usermanual.pdf
41
* VTY Reference: http://ftp.osmocom.org/docs/latest/osmopcu-vty-reference.pdf
42 20 laforge
* Gb/IP Manual: http://ftp.osmocom.org/docs/latest/osmopcu-gb.pdf
43 16 zecke2
44 17 laforge
h2. Source Code
45
46 1 laforge
The source code is available from git://git.osmocom.org/osmo-pcu.git
47
48
You can browse it online via http://cgit.osmocom.org/cgit/osmo-pcu/
49
50 25 laforge
h2. Test Suite
51
52
We have a TTCN-3 test suite as part of our [[cellular-infrastructure:Titan_TTCN3_Testsuites]]
53
* source code: http://git.osmocom.org/osmo-ttcn3-hacks/tree/pcu
54
* results: https://jenkins.osmocom.org/jenkins/view/TTCN3/job/ttcn3-pcu-test/
55
56 16 zecke2
h2. Mailing List
57
58
There is a mailing list for (development) discussion regarding the PCU: osmocom-net-gprs@lists.osmocom.org
59
You can subscribe to it (or manage your subscription) at http://lists.osmocom.org/cgi-bin/mailman/listinfo/osmocom-net-gprs
60 1 laforge
61 21 laforge
Please make sure to read our [[cellular-infrastructure:MailingListRules]] before posting.
62 16 zecke2
63
h3. Supported
64
65
* GPRS CS1 to CS4 with dynamic link/rate adaption
66 1 laforge
* EDGE MCS1-MCS9 with dynamic link/rate adaption
67 16 zecke2
* Single-slot and multi-slot operation on downlink
68
* Single-slot operation on uplink
69
* Independent TFI/USF per PDCH in single-slot allocation mode
70
* Automatic or fixed PDCH allocation algorithm selection
71
* Delayed release of downlink TBF
72
* Active queue management for downlink TBF (!CoDel)
73
* Initial setting of timing advance based on RACH
74
* BSSGP BVC flow control support
75 22 neels
* Using pchan types of @TCH/F_TCH/H_PDCH@ or @TCH/F_PDCH@, OsmoBTS supports
76
  dynamic PDCH/TCH switching (implemented entirely in osmo-bts)
77 1 laforge
78
79 16 zecke2
h3. Shortcomings / Limitations / Restrictions
80 14 jerlbeck
81 22 neels
_Note: this list may be outdated_
82 16 zecke2
83
* No GPRS/EGPRS mixed mode (yet)
84
* No support for hand-over of any sort yet
85
* No support of processing measurement reports
86
* No timing advance loop, i.e. radial movement is limited
87
* No support for power control
88
* No Packet Access Reject message on congestion, access is just ignored
89
* No PCCCH support
90
* Only "Dynamic allocation RLC data block transfer" is supported
91
* No network controlled measurement/cell reselection order supported
92
* No PTCCH support
93
* No support for Packet Flow Contexts (PFC)
94
* No support for MS or PFC flow control
95
* No support for RLC unacknowledged mode operation
96
* No support for MBMS
97
98
h2. Authors / Credits
99
100 1 laforge
101
osmo-pcu was originally developed by Ivan Kluchnikov and Andreas Everberg.
102
103 24 msuraev
Today it is maintaned by Sysmocom.
Add picture from clipboard (Maximum size: 48.8 MB)