You are here: CSP Developer’s Guide: Common Channel Signaling > 2 Introduction to SS7 > SS7 Fault Conditions & Fault Recovery
SS7 Fault Conditions & Fault Recovery
Overview
SS7 stack operations are based on at least one link in a link set on each card in the redundant pair. The stack operations are maintained through the following fault conditions:
• An SS7 card is:
• Removed (host receives Card Status Report message).
• Reset by either the Reset button or with the Reset Configuration message.
• Taken out of service either by the host with the Service State Configure message or by the CSP.
• Malfunctions and forces a reset.
• The redundancy link between the two SS7 cards is broken because:
• The I/O card(s) is removed.
• The card-to-card link on the bus is lost.
Important! The Stop button (on a given card) should always be pushed before removing that card from the system. The PPL Event Indications may not be generated if the SS7 card is pulled without first pressing the Stop button.
The table below shows the results and host action required in response to each fault scenario.
Event |
Result |
Host Notification |
Action Required |
---|---|---|---|
SS7 card (Active) |
- All answered calls are maintained on the remaining SS7 card. |
PPL Event Indication of Signaling link failure (MTP3 LSAC) * CCS Redundancy Report Alarm Card Status Report |
1. Replace SS7 card. 4. Bring Links in service (Service State Configure)
|
SS7 card (Standby)
|
- All answered calls are maintained on the remaining SS7 card.
|
Same as Above |
Same as Above |
SS7 card (Active) |
- All answered calls are maintained on the remaining SS7 card. |
PPL Event Indication of Signaling link failure (MTP3 LSAC) * CCS Redundancy Report (Redundancy Status: 0x29 or 0x30) Alarm Card Status Report for I/O Card Status Report for SS7 CCS Redundancy Report |
No action is required. To suspend synchronization, see Suspending Synchronization in this chapter. |
SS7 card (Standby)
|
- All answered calls are maintained on the remaining SS7 card. - The SS7 card that reset comes back in service with SS7 configuration maintained. |
Same as Above |
Same as Above |
SS7 card taken out of service (Active) |
- All answered calls are maintained on the remaining SS7 card. |
CCS Redundancy Report Card Status Report |
|
SS7 card taken out of service (Standby)
|
- All answered calls are maintained on the remaining SS7 card.
|
Same as Above |
Same as Above |
I/O is removed |
- The active SS7 card currently processing calls remains in service and all calls are maintained. |
CCS Redundancy Report Alarm Alarm (Severity: 0x03 Entity: 0x02 Alarm Number: 0x09) Card Status Report |
1. Replace the I/O card. 4. Bring Links in service (Service State Configure) |
Card-to-card link is broken |
- The SS7 card in the Active state resets. |
CCS Redundancy Report Alarm Card Status Report for I/O Card Status Report for SS7 CCS Redundancy Report |
Check I/O card. It has either faulted or been removed. |