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 Code
Description
800
Normal GTP messages
841
GTP session ended with a GTPv1 Delete message
842
GTP session ended with a GTPv2 Delete message
844
GTP session ended unexpectedly (timeout)
881
GTPv1 session start
882
GTPv2 session start
101000
End User IP address spoofed
101400
GTP-in-GTP
101800
Overbilling protection in effect
104zxx
Tunnel block limit reached
108zxx
Tunnel alert limit reached
1221xx
Incorrect UDP port in GTPv1 header
1222xx
Incorrect UDP port in GTPv2 header
1241xx
Unexpected sequence number in GTPv1 header
1242xx
Unexpected sequence number in GTPv2 header
1281xx
Out-of-state GTPv1 message
1282xx
Out-of-state GTPv2 message
144zxx
Invalid GTP version
1441xx
Incorrect reserved field in GTPv1 header
1442xx
Incorrect reserved field in GTPv2 header
1810xx
Unknown GTP-U message
1811xx
Unknown GTPv1-C message
1812xx
Unknown GTPv2-C message
1821xx
GTPv1 message matched by RAT filter
1822xx
GTPv2 message matched by RAT filter
1841xx
GTPv1 message matched by APN filter
1842xx
GTPv2 message matched by APN filter
1881xx
GTPv1 message matched by IMSI-Prefix filter
1882xx
GTPv2 message matched by IMSI-Prefix filter
20yyxx
Out of order IEs in GTPv1 message
21yyxx
Unknown IE in GTPv1 message (unsupported IE type)
22yyxx
Unknown IE in GTPv2 message (unsupported IE type)
23yyxx
Invalid IE in GTPv1 message, such as invalid IMSI
24yyxx
Invalid IE in GTPv2 message, such as invalid IMSI
26yyxx
Abnormal GTPv1 message length
27yyxx
Abnormal GTPv2 message length
28yyxx
Missing mandatory IE in GTPv1 message
29yyxx
Missing mandatory IE in GTPv2 message
4111xx
Run out of resource for GTPv1 message
4112xx
Run out of resource for GTPv2 message
4121xx
Conflict with another session for GTPv1 message
4122xx
Conflict with another session for GTPv2 message
4141xx
Invalid TEID in GTPv1 header (non-existent tunnel)
4142xx
Invalid TEID in GTPv2 header (non-existent tunnel)

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