GTP Event Codes

GTP logs include event codes to help you troubleshoot issues. A single GTP event type can have more than one event code, and you can find this granular detail is each log. When a GTP session ends, for example, while the GTP event type is recorded as GTP session end, the event code can be 841 or 844. The event code description below will help you decipher whether the session end was triggered with a Delete message or if the session terminated unexpectedly.
The event codes are a hexidecimal format, where xx is the message type, yy is the Information Element (IE) type, and z is the GTP version.
Event CodeDescription
800Normal GTP messages
841GTP session ended with a GTPv1 Delete message
842GTP session ended with a GTPv2 Delete message
844GTP session ended unexpectedly (timeout)
881GTPv1 session start
882GTPv2 session start
101000End User IP address spoofed
101400GTP-in-GTP
101800Overbilling protection in effect
104zxxTunnel block limit reached
108zxxTunnel alert limit reached
1221xxIncorrect UDP port in GTPv1 header
1222xxIncorrect UDP port in GTPv2 header
1241xxUnexpected sequence number in GTPv1 header
1242xxUnexpected sequence number in GTPv2 header
1281xxOut-of-state GTPv1 message
1282xxOut-of-state GTPv2 message
144zxxInvalid GTP version
1441xxIncorrect reserved field in GTPv1 header
1442xxIncorrect reserved field in GTPv2 header
1810xxUnknown GTP-U message
1811xxUnknown GTPv1-C message
1812xxUnknown GTPv2-C message
1821xxGTPv1 message matched by RAT filter
1822xxGTPv2 message matched by RAT filter
1841xxGTPv1 message matched by APN filter
1842xxGTPv2 message matched by APN filter
1881xxGTPv1 message matched by IMSI-Prefix filter
1882xxGTPv2 message matched by IMSI-Prefix filter
20yyxxOut of order IEs in GTPv1 message
21yyxxUnknown IE in GTPv1 message (unsupported IE type)
22yyxxUnknown IE in GTPv2 message (unsupported IE type)
23yyxxInvalid IE in GTPv1 message, such as invalid IMSI
24yyxxInvalid IE in GTPv2 message, such as invalid IMSI
26yyxxAbnormal GTPv1 message length
27yyxxAbnormal GTPv2 message length
28yyxxMissing mandatory IE in GTPv1 message
29yyxxMissing mandatory IE in GTPv2 message
4111xxRun out of resource for GTPv1 message
4112xxRun out of resource for GTPv2 message
4121xxConflict with another session for GTPv1 message
4122xxConflict with another session for GTPv2 message
4141xxInvalid TEID in GTPv1 header (non-existent tunnel)
4142xxInvalid TEID in GTPv2 header (non-existent tunnel)

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