Message Transfer Part Layer 2 (MTP2)
XXX - add a brief description of MTP2 history
- MTP2 is carried by MTP Level 1 which is equivalent to the OSI Physical Layer. It defines the physical, electrical, and functional characteristics of the digital signaling link. Physical interfaces defined include:
- E-1 (2048 kb/s: 32 64 kb/s channels)
- DS-1 (1544 kb/s: 24 64kb/s channels)
- V.35 (64 kb/s)
- DS-0 (64 kb/s)
- DS-0A (56 kb/s)
MTP2 carries MTP3.
In IP networks MTP2 is logically replaced by the SIGTRAN protocols:
XXX - Add example decoded traffic for this protocol here (as plain text or Wireshark screenshot).
The MTP2 dissector is fully functional.
The MTP2 dissector can dissect messages from either traditional (channelized) speed links (64k,56k) or high speed links (unchannelized E1/T1 from Q.703, Annex A), based on the dissector's preference setting. The difference between the two is the size of the sequence numbers.
Example capture file
SampleCaptures/ansi_tcap_over_itu_sccp_over_mtp3_over_mtp2.pcap This capture contains a single MTP2 frame carrying ITU MTP3/SCCP which is carrying an ANSI TCAP message.
A complete list of MTP2 display filter fields can be found in the display filter reference
Show only the MTP2 based traffic:
You cannot directly filter MTP2 while capturing.
- The ITU specifications of MTP2 are available for free on the web: