OAI implements MAC interface for the Wireshark using UDP sockets, which enables Wireshark to disset MAC, RLC, PDCP, RRC (see configuration below). As for the S1AP
, GTP packets, no configuratuon is needed. You can also generate PCAP files.
You need to open Wireshark, open the preferences, and check
for the UDP protocol, MAC-LTE, RLC-LTE, and PDCP-LTE. Then capture for all the interfaces with the following filters:
s1ap or lte_rrc or mac-lte or rlc-lte or pdcp-lte.
Note the L2 pdus are transmitted to the local interface. An example of LTE packet dissection can be found oai_l2l3.pcap
Additional configuration can be found below.
Example for LTE-SOFTMODEM
- Wireshark : lte-softmodem -W (option -p for build_oai.bash)
- Pcap : lte-softmodem -P /tmp/oai.pcap
- Wireshark Control plane only: ./oaisim -a -P wireshark -n 100
- Pcap control plane only: ./oaisim -a -P pcap-n 100, then open oai_opt.pcap
- Wireshark Control plane + data plane: ./oaisim -a -T scbr -P wireshark -n 500
- Pcap Control plane + data plane: ./oaisim -a -T scbr -P pcap -n 500 , then open oai_opt.pcap
- There are currently no preference settings for this protocol.
- Show User-Plane uncompessed data as IP. Default is Off.
- Show unciphered Signalling-Plane data as RRC. Default if Off.
- Attempt to decode ROHC data. Default is Off.
- Try Heuristic LTE-PDCP over UDP framing. Turn on this feature.
- Which layer info to show in Info column. Default is RLC.
- PDCP UE security keys. A table of (UEId, RRCKey, UPKeys) entries.
- Attempt to decipher Signalling (RRC) SDUs. Turn on this feature.
- Attempt to decipher User-plane (IP) SDUs. Default is Off.
- Do sequence analysis for AM channels. Can be done for either standalone RLC frames, or those found inside MAC frames. Default is OFF.
- Do sequence analysis for UM channels. Can be done for either standalone RLC frames, or those found inside MAC frames. Default is OFF.
- Call PDCP dissector for SRB PDUs. Turn on this feature.
- Call RRC dissector for CCCH PDUs. Turn on this feature.
- Try heuristic LTE-RLC framing over UDP. Turn on this feature.
- May see RLC headers only. Default is OFF.
- Attempt SDU reassembly. Turn on this feature.. Will not currently work with out-of-order PDUs or resegmentation.
- Number of Re-Transmits before expert warning triggered. Default is 3.
- Attempt to decode BCH, PCH and CCCH data using LTE RRC dissector. Default is TRUE.
- Dissect frames that have failed CRC check. Default is FALSE.
- Try Heuristic LTE-MAC framing over UDP. Turn on this feature.
- Attempt to dissect LCID 1&2 as srb 1&2. Turn on this feature.
- LCID -> DRB Mappings Table. Can configure data channel ID and RLC mode so that RLC-LTE dissector can be called for these SDUs.
- Attempt to track UL HARQ resends. When frame marked as reTx, looks for link back to original tx. Default is TRUE.
- BSR size when warning should be issued. Default is 50 (19325 < BS <= 22624)
- Track status of SRs within UEs. Looks for and shows links between SR request and resulting grant or failure indication. Default is TRUE. Not implemented
- Which layer info to show in Info column. Choices are PHY, MAC or RLC info. Default is MAC-info.
The itti_analyzer tool can be user to analyze the exchanges between RRC<->S1AP, RRC<->PDCP, PDCP<->S1. This needs to be enabled when compiling either oaisim or lte-softmodem using the flag ITTI_ENABLED.
The itti_analizer requires libgtk-3-0 to be installed:
sudo apt-get install libgtk-3-0
The itti_analyzer itself is located in common/utils/itti_analyzer and can be installed using
autoreconf -fi && ./configure && make && sudo make install
For those having a problem on decoding the "oai_opt.pcap" file using
wireshark, especially running with "oaisim -P pcap".
Please do the following:
Edit -> Configuration Profiles -> New
Name as MAC-LTE
Edit -> Preferences -> Protocols -> DLT_USER -> Encapsulations Table
-> New -> User 0 (DLT=147)
Payload Protocol: mac-lte-framed
- 24 Mar 2015
- 22 Oct 2015