Specifications

4 Message Reference
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MSU Message Signal Unit. A data unit that carries signaling information for
call control, transaction processing, network management and
maintenance. Typically, the MSU is carried in the Signaling Information
Field (SIF) of SS7 messages.
MTP Message Transfer Part. Layers 1 to 3 of the SS7 protocol stack broadly
equivalent to the Physical, Data Link and Network layers in the OSI
protocol stack. See also MTP1, MTP2, and MTP3.
MTP1 Message Transfer Part Level 1. An SS7 stack layer that defines the
physical and electrical characteristics of the signaling links of the SS7
network. Signaling links use DS0 channels and carry raw signaling data
at a rate of 48, 56 or 64 kbps.
MTP2 Message Transfer Part Level 2. An SS7 stack layer that provides link-
layer functionality. Ensures that two end points of a signaling link can
reliably exchange signaling messages. It provides error checking, flow
control and sequence checking.
MTP3 Message Transfer Part Level 3. An SS7 stack layer that provides
network-layer functionality. Ensures that messages can be delivered
between signaling points across the SS7 network regardless of whether
the signaling points are directly connected. It provides node
addressing, routing, alternate routing and congestion control.
mtpsl An example utility that can also be used to activate and deactivate
signaling links.
PRBS Pseudo Random Bit Sequence. A technique used for bit error rate
testing on T1/E1/J1 trunks.
RAI Remote Alarm Indication (Yellow alarm).
route An MTP3 concept that determines how signaling is distributed over
linksets. A route consists of a destination point code and the linkset ID
of one or two linksets over which traffic to the destination node should
be routed. When two linksets are provided, the user can choose to load
share traffic or treat the linksets as primary and secondary.
RTM Rear Transition Module. A board installed in the rear of a CompactPCI
chassis that provides physical connections for the adjacent main board
installed in the front of the chassis. See also “main board”.
s7_log A utility that enables messages received from the protocol stack to be
logged in a text file. Typically used for diagnostic purposes.
s7_mgt A utility that performs one time protocol configuration of all protocol
modules using configuration parameters from the config.txt file.
s7_play A utility that can be used to generate messages from a text file and
send them to the system. Typically used for diagnostic purposes.
SCbus Signal Computing bus. A third generation TDM (Time Division
Multiplexed) resource sharing bus that allows information to be
transmitted and received among resources over multiple data lines.
Provides a total of 1024 timeslots available to devices that require
connection to the bus.
SCCP Signal Connection Control Part. An SS7 stack layer that allows a
software application at a specific node in an SS7 network to be
addressed.