MTP2:Proving Emergency

Before an MTP2 link can be considered as active, both sides of the connection needs to go through a handshake to ensure the ready state of each peer and to test the quality of the physical transport layer (e.g., the timeslot(s)). This handshaking action involves different MSU exchanged between both MTP2 layers.

Two different handshaking methods are available for an MTP2 link: normal and emergency. In both cases, the MTP2 link is considered activated if no errors are detected during the proving period. The "emergency" mode is used to test the link minimally and to bring it up as quickly as possible. Therefore, it has the smallest proving period timer. The typical value is 500 milliseconds (0.5 seconds) for ITU and 600 milliseconds (0.6 seconds) for ANSI.