IMG 1010 - SS7 Link OOS Handling

Owned by Kelli Higdon
Last updated: Mar 04, 2024
3 min read

Configuration:

Screen capture below displays how to enable the IMG so that if an SS7 link goes Out Of Service that the associated CIC's stay in service either a set amount of time (2 minutes), or till certain conditions are met. Screen capture below was taken from IMG set up as an E1 box (ITU). The procedure is the same for T1 (ANSI).

Feature F-5134 SS7 Link Out Of Service was added to software 10.5.2_ER3 only. The feature was not added to any other build until 10.5.3_ER1. From there, all subsequent builds after 10.5.3_ER1 will have the feature in it.

 

Functionality:

Disable (Default)- Functionality is same as previous software.

On loss of signaling accessibility:

  • All associated CICs are immediately brought out of service.

On restore of signaling accessibility

  • All associated CICs are returned to service. 

 

Enable:

On loss of signaling accessibility:

  • Associated CICs in the connected state remain in service.

  • Associated CICs in the inbound ringing state remain in service.

  • All other CICs are immediately brought out of service.

During the loss of signaling accessibility:

  • Calls released from the remote call leg are brought out of service.

  • A 2 minute timer is running, if this timer expires all associated CICs not already out of service are then brought out of service (purge).

On restore of signaling accessibility:

  • All associated CICs not already out of service are then brought out of service (purge).

  • All associated CICs are then returned to service.

 

If signaling link goes Out Of Service all associated CIC's which are in the idle state will go Out Of Service. If any CIC's are in either the ringing or connected state the CIC's will not go Out Of Service until a later subsequent condition occurs as described below.

  • If SS7 Link goes down, all associated idle CIC's (Not being used/controlled by an SS7 link) will immediately go Out Of Service.

  • SS7 Link goes down while call was in the connected state. Once the call is hanged up, the associated CIC will be taken Out Of Service

  • If SS7 Link goes Out Of Service and then comes back into service while the call was in the connected state the call will be dropped when SS7 link comes back into service. The CIC will then be set to an idle state.

  • Once SS7 signaling link goes down, a 2 minute timer is started. Once the timer expires, all CIC's will immediately be taken Out Of Service.

  • A call is being made from SS7 to SIP and the SS7 link goes down while associated CIC is in the ringing state. The IMG will keep the CIC In Service until 2 minute timer expires. After that CIC is taken Out Of Service.

  • A call is being made from SIP to SS7 and the SS7 link goes down while associated CIC is in the ringing state. The IMG will take the CIC Out Of Service.

  • A call is being made from SIP to SS7 and the SS7 link goes down and then comes back into Service while associated CIC is in the ringing state. The IMG will abort the call and set CIC back to its idle state.

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