Project

General

Profile

FakeTRX » History » Version 37

fixeria, 04/19/2019 06:20 PM

1 1 fixeria
h1. FakeTRX (Virtual Um-interface)
2 1 fixeria
3 37 fixeria
FakeTRX is a virtual Um-interface implementation written in Python, that allows to connect both [[OsmocomBB:]] and [[OsmoBTS:]] without the actual RF hardware. The main purpose of this software is to facilitate and simplify development and testing process. In other words, you don't need to physically run your GSM network nor use any kind of special hardware - just run a few scripts and do anything you want / need in your virtual GSM network!
4 37 fixeria
5 37 fixeria
h2. Source code
6 37 fixeria
7 37 fixeria
FakeTRX is a part of [[OsmocomBB:]]. The source code is available at git.osmocom.org.
8 37 fixeria
9 37 fixeria
You can browse it via cgit: https://git.osmocom.org/osmocom-bb/tree/src/target/trx_toolkit, and download using git:
10 37 fixeria
11 37 fixeria
<pre>
12 37 fixeria
$ git clone git://git.osmocom.org/osmocom-bb.git
13 37 fixeria
</pre>
14 37 fixeria
15 37 fixeria
Contributions are welcome via [[cellular-infrastructure:Gerrit]].
16 1 fixeria
17 1 fixeria
h2. FAQ
18 1 fixeria
19 3 fixeria
h3. What is the difference from [[cellular-infrastructure:Virtual_Um|VIRT-PHY]]?
20 1 fixeria
21 36 fixeria
The main difference is that FakeTRX basically works on GSM L1 and deals with bursts, while [[cellular-infrastructure:Virtual_Um|VIRT-PHY]] works on GSM L2, using GSMTAP and multicast sockets to exchange MAC-blocks. FakeTRX provides the [[TRX Interface]] for both [[OsmocomBB:]] and [[OsmoBTS:]], and forwards GSM bursts between both sides. So, there is no need to do any modifications in the [[OsmoBTS:]] source code, just use osmo-bts-trx.
22 1 fixeria
23 1 fixeria
h3. Python?
24 1 fixeria
25 1 fixeria
Of course, Python is slower than C, for example. But it's more than enough for exchanging UDP messages between [[OsmocomBB:]] and [[OsmoBTS:]], and vice versa. Moreover, it can be easily reimplemented in C, if someone interested in better performance.
26 1 fixeria
27 19 msuraev
Once multiple instances are supported, we can benchmark to see what's the preformance bottleneck.
28 19 msuraev
29 5 fixeria
h3. What about RSSI and ToA (Timing of Arrival)?
30 1 fixeria
31 5 fixeria
Since we are talking about the virtual interface, it's possible to emulate any values for both RSSI and ToA.
32 1 fixeria
33 1 fixeria
h3. Can I run multiple BTS and / or multiple MS instances?
34 1 fixeria
35 28 fixeria
Yes (since #3667 is done)!
36 1 fixeria
37 1 fixeria
h2. Running
38 1 fixeria
39 1 fixeria
This guide assumes that you already have the Osmocom GSM [[cellular-infrastructure:|network side stack]] compiled and installed. If not, the simplest way is to use the [[osmonitb:|Network in the Box]].
40 1 fixeria
41 13 msuraev
{{graphviz_link()
42 13 msuraev
digraph G {
43 13 msuraev
    rankdir = LR;
44 13 msuraev
    subgraph cluster_M {
45 33 fixeria
        L23APP1 [label="L2&3 app (e.g. mobile)"];
46 33 fixeria
        L23APP2 [label="L2&3 app (e.g mobile)"];
47 33 fixeria
        TTCN3MS [label="TTCN-3 TC (MS side)"];
48 30 fixeria
        TRXcon1 [label="trxcon"];
49 30 fixeria
        TRXcon2 [label="trxcon"];
50 30 fixeria
        TRXcon3 [label="trxcon"];
51 1 fixeria
        label = "Mobile side";
52 13 msuraev
    }
53 30 fixeria
54 30 fixeria
    FakeTRX [label="FakeTRX"];
55 30 fixeria
56 1 fixeria
    subgraph cluster_N {
57 1 fixeria
        OsmoBSC;
58 33 fixeria
        TTCN3NET [label="TTCN-3 TC (BTS side)"];
59 1 fixeria
        OsmoBTS1 [label="osmo-bts-trx"];
60 1 fixeria
        OsmoBTS2 [label="osmo-bts-trx"];
61 30 fixeria
        OsmoBTS3 [label="osmo-bts-trx"];
62 1 fixeria
        label = "Network side";
63 1 fixeria
    }
64 30 fixeria
65 30 fixeria
    L23APP1 -> TRXcon1 [label="L1CTL"];
66 30 fixeria
    L23APP2 -> TRXcon2 [label="L1CTL"];
67 30 fixeria
    TTCN3MS -> TRXcon3 [label="L1CTL"];
68 30 fixeria
69 30 fixeria
    TRXcon1 -> FakeTRX [label="TRX Interface"];
70 30 fixeria
    TRXcon2 -> FakeTRX [label="TRX Interface"];
71 30 fixeria
    TRXcon3 -> FakeTRX [label="TRX Interface"];
72 30 fixeria
73 30 fixeria
    FakeTRX -> OsmoBTS1 [label="TRX Interface"];
74 30 fixeria
    FakeTRX -> OsmoBTS2 [label="TRX Interface"];
75 30 fixeria
    FakeTRX -> OsmoBTS3 [label="TRX Interface"];
76 13 msuraev
    OsmoBTS1 -> OsmoBSC;
77 13 msuraev
    OsmoBTS2 -> OsmoBSC;
78 30 fixeria
    OsmoBTS3 -> TTCN3NET;
79 13 msuraev
    }
80 13 msuraev
}
81 13 msuraev
}}
82 29 fixeria
83 30 fixeria
[[TRX Interface]] is a part of the upstream [[OsmocomBB:]], just make sure that you have compiled the latest version of [[TRX Interface#The-trxcon-application|trxcon]] application. FakeTRX is a part of TRX toolkit, that is located in 'src/target/trx_toolkit/'. See README for more details.
84 1 fixeria
85 1 fixeria
_Tip: feel free to use tmux or screen to avoid a mess with multiple windows_
86 1 fixeria
87 1 fixeria
1. Run the network side stack you have. In this example we will use the [[osmonitb:|Network in the Box]]:
88 1 fixeria
89 1 fixeria
<pre>
90 1 fixeria
$ osmo-nitb -c ./openbsc.cfg -l ./hlr.sqlite3 -P -C --debug=DRLL:DCC:DMM:DRR:DRSL:DNM
91 1 fixeria
</pre>
92 1 fixeria
93 31 fixeria
2. Run the fake_trx.py:
94 1 fixeria
95 6 fixeria
<pre>
96 23 msuraev
$ cd osmocom-bb/src/target/trx_toolkit/
97 31 fixeria
$ python ./fake_trx.py
98 1 fixeria
</pre>
99 11 osmith
100 31 fixeria
3. Start [[OsmoBTS:]]:
101 1 fixeria
102 1 fixeria
<pre>
103 23 msuraev
$ osmo-bts-trx -c ./osmo-bts.cfg
104 23 msuraev
</pre>
105 23 msuraev
106 1 fixeria
Congratulations! Now you have a virtual GSM network running. As you can see, the virtual transceiver emulates the clock source, as this is required for [[OsmoBTS:]]. Also, it handles only a few important commands, such as RXTUNE and TXTUNE, but ignores other irrelevant ones.
107 1 fixeria
108 31 fixeria
4. In order to "bridge" [[Host_Software|L2&3 applications]] with FakeTRX, you need to run [[TRX Interface#The-trxcon-application|trxcon]]:
109 1 fixeria
110 23 msuraev
<pre>
111 1 fixeria
$ cd osmocom-bb/src/host/trxcon/
112 31 fixeria
$ ./trxcon
113 23 msuraev
</pre>
114 1 fixeria
115 1 fixeria
5. Finally, run any L2&3 application, e.g. ccch_scan:
116 1 fixeria
117 1 fixeria
<pre>
118 1 fixeria
$ cd osmocom-bb/src/host/layer23/src/misc/
119 1 fixeria
$ ./ccch_scan -a ARFCN -i 127.0.0.1
120 1 fixeria
</pre>
121 1 fixeria
122 1 fixeria
Please note that ARFCN value should match the one your BTS configured to.
123 1 fixeria
124 31 fixeria
At this stage, you should see the broadcast messages coming from the virtual network, like in case of a real one. You can use Wireshark to analyze them.
125 1 fixeria
126 1 fixeria
h2. Running [[mobile]] application
127 12 osmith
128 1 fixeria
As you should already know, [[mobile]] applications implements a simple mobile phone with SMS, USSD and voice calls. In the virtual network we can benefit from using a virtual SIM card. Just configure one according to your network configuration, see the example below. If you are starting with the default config from the source tree (@osmocom-bb/doc/examples/mobile/default.cfg@), make sure to change @sim reader@ to @sim test@ in the @ms 1@ section.
129 1 fixeria
130 1 fixeria
<pre>
131 1 fixeria
test-sim
132 1 fixeria
  imsi 901700000000000
133 1 fixeria
  no barred-access
134 1 fixeria
  rplmn 901 70
135 1 fixeria
</pre>
136 1 fixeria
137 1 fixeria
Make sure you have the virtual network running, then run mobile the same way as in case of a Calypso based phone:
138 1 fixeria
139 1 fixeria
<pre>
140 1 fixeria
$ cd osmocom-bb/src/host/layer23/src/mobile/
141 1 fixeria
$ ./mobile -i 127.0.0.1
142 1 fixeria
</pre>
143 1 fixeria
144 1 fixeria
Now you can use mobile's telnet interface to manage your virtual phone:
145 1 fixeria
146 1 fixeria
<pre>
147 1 fixeria
$ telnet localhost 4247
148 1 fixeria
$ ...
149 1 fixeria
</pre>
150 1 fixeria
151 34 fixeria
h2. Multiple transceivers
152 34 fixeria
153 34 fixeria
It's possible to handle multiple MS and/or BTS connections in a single [[FakeTRX]] process using _--trx_ option.
154 34 fixeria
155 34 fixeria
Additional MS-/BTS-side transceiver:
156 34 fixeria
157 34 fixeria
<pre>
158 34 fixeria
$ ./fake_trx.py --trx 127.0.0.1:6703
159 34 fixeria
</pre>
160 34 fixeria
161 34 fixeria
Two child transceivers of the main BTS:
162 34 fixeria
163 34 fixeria
<pre>
164 34 fixeria
$ ./fake_trx.py --trx 127.0.0.1:5700/1 --trx 127.0.0.1:5700/2
165 34 fixeria
</pre>
166 34 fixeria
167 34 fixeria
Additional transceiver with name:
168 34 fixeria
169 34 fixeria
<pre>
170 34 fixeria
$ ./fake_trx.py --trx foo@127.0.0.1:5703
171 34 fixeria
</pre>
172 34 fixeria
173 34 fixeria
Additional transceiver with IPv6 address:
174 34 fixeria
175 34 fixeria
<pre>
176 34 fixeria
$ ./fake_trx.py --trx ipv6@[2001:0db8:85a3:0000:0000:8a2e:0370:7334]:5700/5
177 34 fixeria
</pre>
178 34 fixeria
179 1 fixeria
h2. Demo
180 1 fixeria
181 1 fixeria
https://www.youtube.com/watch?v=Uxdaui8EkjY
182 1 fixeria
183 1 fixeria
h2. Project status
184 10 fixeria
185 10 fixeria
Supported:
186 10 fixeria
187 10 fixeria
* Simulation and randomization of both RSSI and ToA
188 32 fixeria
* Multiple MS / BTS transceivers (see #3667)
189 10 fixeria
* Burst capture to file (see data_dump.py)
190 1 fixeria
* Injection of bursts and commands
Add picture from clipboard (Maximum size: 48.8 MB)