There are many variation of PDU formats specified by the various 3GPP Protocols. All supported 3GPP operations and data formats are described below:
- GSM:
- Supported PDU types:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| |
+ IV (8/16byte) |
| |
+>+-+-+-+-+-+-+-+-+
| | |
| | |
| | Data |
| | |
| | |
| +-+-+-+-+-+-+-+-+
|
|-> Ciphering Unit
Figure 1. Ciphering Unit of a GSM PDU.
- Ciphering algorithm: GSM A5/3, ECSD A5/3, GAE3, Kasumi-F8
- Key Stream Generation:
- Input to SA: 64-bit IV plus all zero payload
- Output from SA: 64-bit IV plus key stream (228 bit for GSM A5/3, 696 bit for ECSD A5/3, varialbe length for GAE3)
- Full Encryption/Decryption:
- Input to SA: 64/128-bit IV plus payload
- Output from SA: 64/128-bit IV plus encryped/decrypted paylaod
- WCDMA:
- Supported PDU types:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|DC| Seq Num |
+-+-+-+-+-+-+-+-+
|Seq Num |P| HE|
+>+-+-+-+-+-+-+-+-+
| | Length Ind. |E|
| +-+-+-+-+-+-+-+-+
| | |
| | |
| | Data |
| | |
| | |
| +-+-+-+-+-+-+-+-+
| | PAD or piggy-backed STATUS PDU
| +-+-+-+-+-+-+-+-+
|
|-> Ciphering Unit
Figure 2. Ciphering Unit of a WCDMA AMD PDU.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| Seq Num |E|
+>+-+-+-+-+-+-+-+-+
| | Length Ind. |E|
| +-+-+-+-+-+-+-+-+
| | |
| | |
| | Data |
| | |
| | |
| +-+-+-+-+-+-+-+-+
|
|-> Ciphering Unit
Figure 3. Ciphering Unit of a WCDMA UMD PDU.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| |
| Count-C |
| (4-byte) |
| |
+>+-+-+-+-+-+-+-+-+
| | |
| | |
| | Data |
| | |
| | |
| +-+-+-+-+-+-+-+-+
|
|-> Ciphering Unit
Figure 4. Ciphering Unit of a WCDMA TMD PDU.
- Ciphering algorithm: Kasumi/F8,Snow 3G/F8, AES-CTR
- From Air Traffic (Decryption) :
- Input to SA:
- PDU header plus payload for RLC AMD/UMD PDU
- Payload with 32-bit Count-C in the CPPI header for TMD MAC PDU
- Output from SA:
- PDU header plus decrypted payload for RLC AMD/UMD PDU
- Decrypted payload for TMD MAC PDU
- To Air Traffic (Encryption) :
- Input to SA:
- PDU header plus payload for RLC AMD/UMD PDU
- Payload for TMD MAC PDU
- Output from SA:
- PDU header plus encrypted payload for RLC AMD/UMD PDU
- 32-bit Count-C plus encrypted payload for TMD MAC PDU
- LTE:
- Supported PDU types:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| |
| Count-C |
| (4-byte) |
| |
+>+-+-+-+-+-+-+-+-+
| | |
| | |
| | Data |
| | |
| | |
| +-+-+-+-+-+-+-+-+
|
|-> Ciphering Unit
Figure 5. Ciphering Unit of a PDCP Data PDU.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ <+
|R R R| PDCP SN | |
+>+-+-+-+-+-+-+-+-+ |
| | | |
| | | |
| | Data | |
| | | |
| | | |
| +-+-+-+-+-+-+-+-+ |-> Authentication Unit
| | MAC-I |
| | (4 byte) |
| +-+-+-+-+-+-+-+-+
|
|-> Ciphering Unit
Figure 6. PDCP Control Plane Data Uint for SRBs
- Ciphering algorithm: Snow 3G/F8, AES-CTR Authentication algorithm: CMAC
- From Air Traffic (Decryption and/or Authentication verification) :
- Input to SA:
- PDCP Data with 32-bit Count-C in the CPPI header for the Data Plane PDU
- PDCP Header plus Data and MAC-I with 32-bit Count-C in the CPPI header for the Control Plane PDU
- Output from SA: 32-bit Count-C plus decrypted PDCP PDU Data
- PDCP Data for the Data Plane PDU
- PDCP Header plus Data and MAC-I for the Control Plane PDU
- To Air Traffic (Encryption and/or Authentication) :
- Input to SA:
- PDCP Data for the Data Plane PDU
- PDCP Header plus Data and MAC-I with 32-bit Count-C in the CPPI header for the Control Plane PDU
- Output from SA: 32-bit Count-C plus encrypted PDCP PDU Data
- 32-bit Count-C plus PDCP Data for the Data Plane PDU
- PDCP Header plus Data and MAC-I for the Control Plane PDU