GTPU Tab

The N3 Interface — Provides a reference point between (R) AN and the UPF. Used in the AMF (Access and Mobility Function) Nodal , gNB CU Node,and UPF Node Test Cases. Per 3GPP TS 23.501, TS 29.281 vf20, TS 38.415 v100.

The Xn-U interface provides non-guaranteed delivery of user plane PDUs between two NG-RAN nodes. Available in gNB CU Node test case when Xn Interface is enabled.

General Parameters

GTP-U Include Sequence Number
GTP-U Include QFI
- GTP-U Include DL QFI Sequence Number
- GTP-U Include UL QFI Sequence Number

GTP-U Include Sequence Number

Select to include the GTP-U sequence number. Not available when Fireball is enabled.

Checking "Support URLLC" on AMF Nodal will automatically check "GTP-U Include Sequencer Number" on the N3|GTP-U tab but it can be unchecked afterwards.

When "Support URLLC" is checked on AMF Nodal , either "GTP-U Include Sequence Number" or "GTP-U Include UL QFI Sequence Number" must be checked.

Tcl Parameter: GnbN3GtpuIncludeSeqNum

Tcl Parameter: UpfN3GtpuIncludeSeqNum

Tcl Parameter: XnuGtpuIncludeSeqNum

GTP-U Include QFI

GTP-U Include DL QFI Sequence Number

GTP-U Include UL QFI Sequence Number

Select to include the GTP-U QFI (Qos Flow ID). When "Support URLLC" is checked on AMF Nodal , either "GTP-U Include Sequence Number" or "GTP-U Include UL QFI Sequence Number" must be checked.

For UPF Node, checkbox "GTP-U Include DL QFI Sequence Number" is unchecked by default and shall be disabled if the "GTP-U Include QFI" box is unchecked.

The data packets, if URLLC is enabled, are duplicated and sent over the redundant tunnels and the same "GTP-U Sequence number" or "DL/UL QFI sequence number" or both is maintained for both the packets.

Example: When URLLC is enabled, an uplink packet with sequence number 2, TEID 2000000 is duplicated and sent over the redundant tunnel (TEID: 2000001) with the same sequence number 2. At UPF, when packet with sequence number 2 is received it is forwarded. The second packet with the same sequence number is discarded. Same applies for the downlink traffic.

On AMF Nodal, under the "gNB User Node" and "gNB Control Node" tabs and on UPF Node, under the "UPF N3 Node" tab, the following measurements measure the corresponding number of packets/bytes.

Total Redundant Packets Received
Total Redundant Packets Sent
Total Redundant Packets
Total Redundant Bytes Received
Total Redundant Bytes Sent
Total Redundant Bytes
Total Received Redundant Packets Discarded - Original Tunnel
Total Received Redundant Packets Discarded - Redundant Tunnel
Total Received Redundant Bytes Discarded - Original Tunnel
Total Received Redundant Bytes Discarded - Redundant Tunnel

Limitation :

When this feature is active, capacity and performance degradation is expected since the gNB and/or UPF Node will be sending/processing twice as many data packets as when this feature is not active.

Tcl Parameter: GnbN3GtpuIncludeQfi

Tcl Parameter: GnbN3GtpuUlQfiSeqNumEn

Tcl Parameter: UpfN3GtpuIncludeQfi

Tcl Parameter: UpfN3GtpuDlQfiSeqNumEn

Tcl Parameter: XnuGtpuIncludeQfi

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