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Error codes › GTPv2-C cause

GTPv2 cause 128 S1-U Path Failure

GTPv2-C cause3GPP TS 29.274 §8.4 (Table 8.4-1)

What it means

The S1-U user-plane path failed (S1-U Path Failure) -- a transport/bearer-plane issue, separate from the GTP-C control-plane signaling itself.

Where you see it

In the Cause IE of a GTPv2-C response (Create Session, Modify Bearer, Delete Session…) on S11, S5 or S8.

What to check

Check the S1-U transport path (IP connectivity) between the eNodeB and the SGW/PGW.

Check which node sent the response (MME, SGW or PGW): the cause belongs to that node's decision.

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