link status signal unit (SS7) (LSSU)
The Link Status Signal Unit (LSSU) is a signalling unit in SS7 signaling that is used tocheck the status of the link.
The LSSU unit is a one or two octet long status information that is exchanged between the signaling points. These LSSU units are sent on the signalling links between two Signalling Points( SP) and provide for the adjustment of the link.
The Link Status Signal Unit (LSSU) corresponds in its basic structure to the Message Signal Unit( MSU) or also the Fill-in Signal Unit( FISU) with the difference that the LSSU unit has an 8 or 16 bit long status field( SF). This status field can be used to display one of six different status information.
.png)
Status information indicates activity between Signaling Points (SP) and on Signaling Links( SLK). Status indications include Status Indication Busy( SIB), Status Indication Normal( SIN) or Status Indication Emergency ( SIE). The value for the Length Indicator( LI) is 1 or 2 for LSSU.