Specifications

42 HW-MTP2 Level 2 - Level 3 Interfaces and Message Flows HighWire MTP-2 - 1.2, September 4, 2002
5-3-1. Link activation
Figure 5-1 Message flows involved in registering with an L2 process and activating a link.
1. L3 sends a CBI_M2_REGISTER to L2 to identify the correct MTP3
process with which L2 should communicate. L2 responds to the request
indicating whether the L2 stack initialized successfully.
2. L2 sends a CBI_M2_AVAILABLE to notify the L3 that it has opened the
data interface and is ready to receive further signals.
3. L3 then optionally sends a CBI_M2_UPDATE_PARMS to define the
dynamically changeable parameters in L2. L2 returns the signal as a
response, indicating if the update was successful. If
CBI_M2_UPDATE_PARMS is not issued, the parameters take their
default values.
4. L3 may or may not send a CBI_M2_EMERGENCY signal to request that
L2 perform emergency link proving. This signaling involves exchanging
only a limited set of data proving signals with the peer L2 process to
accelerate the alignment process.
5. L3 sends a CBI_M2_START signal to request that a link be established.
This action initiates the alignment process.
6. L2 sends a CBI_M2_IN_SERVICE to L3 when the link proving phase has
completed successfully. L3 may now transmit and receive data packets.