Message Transfer Part

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The Message Transfer Part (MTP) is part of the Signaling System 7 (SS7) used for communication in Public Switched Telephone Networks. MTP is responsible for reliable, unduplicated and in-sequence transport of SS7 messages between communication partners.

MTP is formally defined primarily in ITU-T recommendations Q.701, Q.702, Q.703, Q.704 and Q.705. Tests for the MTP are specified in the ITU-T recommendations Q.781 for MTP2 and in Q.782 for MTP3. These tests are used to validate the correct implementation of the MTP protocol.

Different countries use different variants of the MTP protocols. In North America, the formal standard followed is ANSI T1.111. In Europe, national MTP protocols are based on ETSI EN 300-0088-1.