Path Failure Handling
Upon detecting a path failure, the network node notifies the failure through the Operation and Maintenance system and performs the following:
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Deletes the PDN connections (EPS bearer contexts) or the associated PDP contexts with peer IP address.
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Specifies the following actions for the selected interface:
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Local Purge: The cnSGW-C clears the affected bearer (or PDN if the default bearer receives the path failure) locally without informing the peer. This action is default for all interfaces.
NotecnSGW-C sends the Sx Session Delete Request to UPF to clear session on path failure detection.
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Signal-Peer: The cnSGW-C sends control signal towards the peer MME and P-GW.
When signaling:
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For PDN deletion, the SGW sends a Delete Session Request message to the PGW and a Delete Bearer Request (with LBI) message to the MME.
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SGW sends a Delete Request on the S11 or the S5 interface to notify the peer.
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Note | Echo Request exchange is stopped when the peer is deleted. |