The bandwidth of a SS7 signalling link is normally 64 kbit/sec. If a larger bandwidth is
necessary up to 16 links between two signaling points can be used. These links between
two SPs are called a linkset.
The loadsharing in SS7-networks is based on the signaling link selection field (SLS),
a 4-bit integer provided by the userpart in the MTP-TRANSFER primitive.
The point codes of the destination (DPC) and of the origin (OPC) are also provided
by the userpart and the triple consisting of the SLS, OPC and DPC is called routing label
and is part of each MTP-3 protocol data unit, called message signal unit (MSU).
By effectively extending the 4-bit SLS field individual linksets
consisting of up to 16 links each can be fully utilized in a combined linkset.
Due to the 4 bit SLS field the maximum number of links in a linkset (or route) is 16.
To help with load balancing each link should handle a maximum of 40% utilisation. Once exceeded
the SLS bit field will ensure another link is used. This ensures an even distribution of traffic (load) within a defined linkset.
VBR/ Wallis Dudhnath