Content for TR 29.807 Word version: 12.0.0
2 References
3 Definitions, symbols and abbreviations
4 Introduction to GTP-C overload control
5 Load Control Information
6 Overload Control Information
7 Deployment related considerations
8 Heterogeneous network related considerations
9 Conclusions and recommendations
$ Change History
2 References p. 9
3 Definitions, symbols and abbreviations p. 10
4 Introduction to GTP-C overload control p. 10
4.0 GTP-C overload problem p. 10
4.1 Scenarios leading to GTP-C overload p. 11
4.2 GTP-C signalling based Load and Overload Control solution p. 12
4.2.1 Description p. 12
4.2.2 Principles of Load Control p. 12
4.2.3 Principles of Overload Control p. 13
4.2.4 Applicability to 3GPP and non-3GPP access based interfaces p. 13
4.2.4.1 Introduction p. 13
4.2.4.2 GTP-C load control p. 14
4.2.4.2.1 Description p. 14
4.2.4.2.2 Conclusions p. 14
4.2.4.3 GTP-C overload control p. 14
4.2.4.3.1 General p. 14
4.2.4.3.2 Applicability to 3GPP access based interfaces p. 15
4.2.4.3.2.1 Description p. 15
4.2.4.3.2.2 Conclusions p. 16
4.2.4.3.3 Applicability to non-3GPP access based interfaces p. 16
4.2.4.3.3.1 General p. 16
4.2.4.3.3.2 Untrusted WLAN access p. 17
4.2.4.3.3.3 Trusted WLAN access p. 18
4.2.4.3.3.4 Conclusions p. 21
5 Load Control Information p. 21
5.1 General p. 21
5.1A APN level load control p. 21
5.1A.1 Description p. 21
5.1A.2 Requirements p. 21
5.1A.3 Example use case p. 22
5.1A.4 Issues when APN load control is not used p. 23
5.1A.4.1 Node selection using DNS weight-factor only p. 23
5.1A.4.2 Node selection using node level load information and DNS weight-factor p. 23
5.1A.5 Information needed for APN load control p. 24
5.1A.6 Impacts on node level load control p. 24
5.1A.7 Conclusion p. 26
5.2 Definition p. 26
5.2.1 Requirements p. 26
5.2.2 Alternative 1 - New Load Control Information IE piggybacked in existing GTP-C signalling p. 27
5.2.2.1 Description p. 27
5.2.3 Conclusion p. 30
5.3 Frequency of inclusion p. 31
5.3.1 Requirements p. 31
5.3.2 Alternative 1 - Inclusion by piggybacking only when the new/changed value has not been provided to a peer p. 31
5.3.2.1 Description p. 31
5.3.2.2 Using a subset of the applicable messages p. 31
5.3.2.3 Advantages p. 32
5.3.2.4 Drawbacks p. 32
5.3.3 Alternative 2 - Inclusion by piggybacking in every message towards a peer p. 32
5.3.3.1 Description p. 32
5.3.3.2 Using a subset of the applicable messages p. 32
5.3.3.3 Advantages p. 32
5.3.3.4 Drawbacks p. 33
5.3.4 Alternative 3 - Hybrid of Alternative 1 and Alternative 2 p. 33
5.3.5 Alternative 4 - Inclusion by piggybacking the load control information periodically p. 33
5.3.6 Conclusion p. 34
5.4 Interaction with existing mechanisms p. 36
5.4.1 General p. 36
5.4.2 Information received from DNS p. 36
5.5 Limit on maximum number of instances p. 39
5.5.1 Description p. 39
5.5.2 At message level p. 39
5.5.3 At node level p. 39
5.5.3.1 Alternative 1 - Same as at message level & providing full set of information p. 39
5.5.3.2 Alternative 2 - Higher than or same as at message level & providing partial set of information p. 40
5.5.4 Conclusion p. 40
6 Overload Control Information p. 41
6.1 General p. 41
6.2 Definition p. 41
6.2.1 Requirements p. 41
6.2.2 Alternative 1 - New Overload Control Information IE piggybacked in existing GTP-C signalling p. 42
6.2.2.1 Description p. 42
6.2.2.1.1 General p. 42
6.2.2.1.2 Parameters p. 43
6.2.2.1.2.1 Overload-Reduction-Metric p. 43
6.2.2.1.2.2 Period-Of-Validity p. 44
6.2.2.1.2.3 Overload-Sequence-Number p. 44
6.2.2.1.2.4 APN-List p. 45
6.2.2.1.3 Parameter Evaluation p. 46
6.2.3 Conclusion p. 46
6.3 Frequency of inclusion p. 46
6.3.1 Requirements p. 46
6.3.2 Alternative 1 - Inclusion by piggybacking only when the new/changed value has not been provided to a peer p. 47
6.3.2.1 Description p. 47
6.3.2.2 Using a subset of the applicable messages p. 47
6.3.2.3 Advantages p. 47
6.3.2.4 Drawbacks p. 47
6.3.3 Alternative 2 - Inclusion by piggybacking in every message towards a peer p. 48
6.3.3.1 Description p. 48
6.3.3.2 Using a subset of the applicable messages p. 48
6.3.3.3 Advantages p. 48
6.3.3.4 Drawbacks p. 48
6.3.4 Alternative 3 - Hybrid of Alternative 1 and Alternative 2 p. 49
6.3.5 Alternative 4 - Inclusion by piggybacking the overload control information periodically p. 49
6.3.6 Conclusion p. 50
6.4 Message throttling p. 52
6.4.0 General p. 52
6.4.1 Throttling algorithms p. 53
6.4.1.1 General p. 53
6.4.1.2 Throttling by "Loss" algorithm p. 53
6.4.1.2.1 Description p. 53
6.4.1.2.2 Implementation p. 53
6.4.1.2.3 Advantages p. 54
6.4.1.2.4 Drawbacks p. 54
6.4.1.3 Conclusion p. 54
6.4.2 Message prioritization p. 55
6.4.2.1 Description p. 55
6.4.2.2 Based on procedures p. 55
6.4.2.3 Based on session parameters p. 57
6.4.2.4 Conclusion p. 57
6.5 Propagation of MME/S4-SGSN identity to PGW p. 57
6.5.1 Description p. 57
6.5.2 Updating PGW with current serving MME/S4-SGSN identity p. 57
6.5.2.1 Introduction p. 57
6.5.2.2 Alternative 1: Always send MBReq over S5/S8 p. 58
6.5.2.3 Alternative 2: Only send MBReq over S5/S8 normally p. 58
6.5.2.4 Alternative 3: Opt Alt 2 - send over S5/S8 if not provided previously p. 58
6.5.2.5 Alternative 4: Send MBReq over S5/S8 when source in overload p. 58
6.5.2.6 Conclusion p. 59
6.5.3 Updating PGW with overload control information of target MME/S4-SGSN p. 59
6.6 Interaction with existing mechanisms p. 60
6.6.1 DDN throttling p. 60
6.6.1.1 Description p. 60
6.6.1.2 Conclusion p. 61
6.6.2 Congestion control using APN back-off timer p. 61
6.7 Enforcement of overload control p. 63
6.7.1 General p. 63
6.7.2 Aspects related to enforcement of the overload control p. 63
6.7.2.1 Good throughput of the network p. 63
6.7.2.2 Message processing efficiency at the source node p. 63
6.7.2.3 Self-protection by the target node p. 63
6.7.3 Enforcement approaches p. 64
6.7.3.1 Hop-by-hop only p. 64
6.7.3.1.1 Description p. 64
6.7.3.1.2 Example scenario p. 64
6.7.3.1.3 Advantages p. 64
6.7.3.1.4 Drawbacks p. 65
6.7.3.2 End-to-end only p. 65
6.7.3.2.1 Description p. 65
6.7.3.2.2 Example scenario p. 65
6.7.3.2.3 Advantages p. 65
6.7.3.2.4 Drawbacks p. 66
6.7.3.3 End-to-end and intermediate node p. 66
6.7.3.3.1 Description p. 66
6.7.3.3.2 Example scenario p. 66
6.7.3.3.2.1 Overload condition p. 66
6.7.3.3.2.2 Outcome of the overload control enforcement - Implementation 1 p. 67
6.7.3.3.2.3 Outcome of the overload control enforcement - Implementation 2 p. 67
6.7.3.3.3 Advantages p. 68
6.7.3.3.4 Drawbacks p. 68
6.7.4 Conclusion p. 68
6.8 Behaviours of GTP-C entities p. 69
6.9 Limit on maximum number of instances p. 69
6.9.1 Description p. 69
6.9.2 At message level p. 69
6.9.3 At node level p. 70
6.9.3.1 Alternative 1 - Same as at message level & providing full set of information p. 70
6.9.3.2 Alternative 2 - Higher than or same as at message level & providing partial set of information p. 70
6.9.4 Conclusion p. 71
7 Deployment related considerations p. 72
7.1 General p. 72
7.2 Discovery of the support of the feature by the peer node p. 72
7.2.1 Description p. 72
7.2.2 Across the PLMN boundary p. 72
7.2.3 Within the PLMN boundary p. 72
7.2.3.1 Alternative 1 - Using protocol based indicator p. 72
7.2.3.1.1 Advantages p. 72
7.2.3.1.2 Drawbacks p. 72
7.2.3.2 Alternative 2 - Using PLMN-wide local configuration p. 73
7.2.3.2.1 Advantages p. 73
7.2.3.2.2 Drawbacks p. 73
7.2.4 Conclusion p. 73
8 Heterogeneous network related considerations p. 73
8.1 General p. 73
8.2 Implicit overload control mechanisms p. 74
8.3 Issues in the network with partial support of the feature p. 74
9 Conclusions and recommendations p. 75
$ Change History p. 78
