8.40 PDU Numbers
29.2743GPP3GPP Evolved Packet System (EPS)Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C)Release 18Stage 3TS
The PDU Numbers information element contains the sequence number status corresponding to a Bearer context in the old SGSN. This information element shall be sent only when acknowledged peer-to-peer LLC operation is used for the Bearer context or when the "delivery order" QoS attribute is set in the Bearer context QoS profile.
NSAPI identifies the Bearer context for which the PDU Number IE is intended.
DL GTP-U Sequence Number is the number for the next downlink GTP-U T-PDU to be sent to the UE when "delivery order" is set.
UL GTP-U Sequence Number is the number for the next uplink GTP-U T-PDU to be tunnelled to the S-GW when "delivery order" is set.
The Send N-PDU Number is used only when acknowledged peer-to-peer LLC operation is used for the Bearer context. Send N-PDU Number is the N-PDU number to be assigned by SNDCP to the next down link N-PDU received from the S-GW.
The Receive N-PDU Number is used only when acknowledged peer-to-peer LLC operation is used for the Bearer context. The Receive N-PDU Number is the N-PDU number expected by SNDCP from the next up link N-PDU to be received from the UE.
The PDU Number IE will be repeated for each Bearer Context for which this IE is required.
PDU Numbers IE is coded as depicted in Figure 8.40-1.
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Bits |
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Octets |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
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1 |
Type = 110 (decimal) |
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2 to 3 |
Length = n |
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4 |
Spare |
Instance |
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5 |
Spare(0 0 0 0) |
NSAPI |
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6-7 |
DL GTP-U Sequence Number |
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8-9 |
UL GTP-U Sequence Number |
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10-11 |
Send N-PDU Number |
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12-13 |
Receive N-PDU Number |
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14 to (n+4) |
These octet(s) is/are present only if explicitly specified |
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Figure 8.40-1: PDU Numbers