Revision as of 19:38, 31 August 2009 by Ktrueman (initial content from SS7 user guide)
The MTP1 layer is the physical layer and is responsible of the actual HDLC framing of SS7 packets (usually called MSU – Message signaling unit). Beside the transmission and reception of frames, calculation of CRC, this layer is also responsible to monitor and report the quality of the link based on the number of failures detected (CRC errors, unexpected packets). Using specially formatted packets (LSSU and FISU), this layer makes sure the communication with the peer side is always valid and synchronized, even when the communication link is supposedly idle (no MSU being sent).
TelcoBridges and MTP1
TelcoBridges supports MTP2 as part of its SS7 signaling stack.