ZTE Corporation ZXG-BTS2 Benutzerhandbuch
ZXG10-BTS (V2.9) Technical Manual
72
Confidential and Proprietary Information of ZTE CORPORATION
F
I G U R E
4 8
E
N C R Y P T I O N
MS
LAPD
FURRM
HPIMa
LAPD
BSC
OAMM
(ENCR CMD)
DL_DATA_IND (ENCR CMD)
MPH_RRCmdToCHP
(CHP START
DECRYPTION)
MPH_CHPIndToRR
(CHP CRYPTION
RESP (ACK))
Dm_DL_DATA_
REQ (CIPH
MODE CMD)
(CIPH MODE CMD)
DL_DATA_REQ (DATA REQ
(CIPH MODE COM))
Dm_DL_DATA_IND
(CIPH MODE COM)
DATA REQ (CIPH
MODE COM)
(CIPH MODE COM)
MPH_RRCmdToCHP
(CHP START
ENCRYPTION)
To set an encryption mode for the network means specifying whether the
transmission needs to be encrypted and which algorithm should be used.
This procedure is initiated after the BSC receives the CIPHER MODE
COMMAND message from the MSC. The ENCR CMD message that is sent
by the BSC to the TRX and related channel contains all information to be
selected, loading user data, encryption equipment and the complete (RR)
by the BSC to the TRX and related channel contains all information to be
selected, loading user data, encryption equipment and the complete (RR)
CIPH MODE CMD message that is sent to the MS.
When the ENCR CMD is received, the TRX sends the (RR) CIPH MODE CMD
to the MS in the non-encryption mode, and begins the decryption at the
same time (the CHP implements this operation).The BTS, at this time,
same time (the CHP implements this operation).The BTS, at this time,
actually sends configurations in the old mode, and receives configurations
in the new mode.
in the new mode.
When the MS receives the (RR) CIPH MODE CMD, it will be configured into
the complete new mode, and sends the (RR) CIPH MOD COM to the BTS.
Whenever the BTS receives a correctly decoded message (in the new
the complete new mode, and sends the (RR) CIPH MOD COM to the BTS.
Whenever the BTS receives a correctly decoded message (in the new
mode), it indicates that the MS has been correctly changed into the new
mode. Only after that, the BTS fully changes into the new mode, and the
mode. Only after that, the BTS fully changes into the new mode, and the
sending is also in the new mode (the CHP implements this operation).
If the TRX cannot implement encryption according to the ENCR CMD
requirement for some reasons, the CHP sends the CHP CYPTION
RESPONSE (NACK) message to the FURRM, and then the FURRM returns
RESPONSE (NACK) message to the FURRM, and then the FURRM returns
an ERROR REPORT message, with the cause “Encryption algorithm cannot
be executed” for example.
be executed” for example.
If the (RR) CIPH MODE CMD message is considered wrong, the MS returns
a (RR) RR STATUS message with the cause “Protocol error unspecified”
and perform no operation after that.
and perform no operation after that.