MTP2:Architecture

A MTP2 Link must be associated with one Trunk instance. It’s a 1 to 1 association. MTP Level 2 defines the functions and procedures of the signaling system for providing reliable transfer of signaling messages over a signaling link.

Important note: It is important to ensure that the received and transmitted clocks of the Trunk were synchronized. This can be useful for removing/limiting undesirable FIB and BSN errors. See section “Clock Configurations” in the TB640 user’s guide.

Priorities

No pre-emption of data occurs in the process of being transmitted or requiring retransmission. Only a single congestion priority is supported for ANSI and ITU. For a TTC/NTT link, transmitted data buffers are prioritized based on the priority indicated by MTP Level 3.

Flow control

The MTP Level 2 software regulates data flow when resource utilization (such as buffer pool size or queue length) reaches specifies thresholds. For each threshold, MTP Level 2 performs one of the following actions:

• Informs the layer manager about flow control.
• Sends a link status signal unit with status "B" (busy).
• Sends a flow control indication to the upper layer.

The MTP Level 2 software prevents deadlocks and overload conditions from occurring.