Dialogic DSI SS7MD manual Ima frame length Length of the IMA frame, Bit Mnemonic Description

Dialogic® DSI SS7MD Programmer’s Manual Issue 3

•options

Bit	Mnemonic	Description
0	ATM_CFG_OPTIONS_SCRAMBLE	Enable payload scrambling
1	ATM_CFG_OPTIONS_COSET	Use ATM coset in HEC calculation
2	ATM_CFG_OPTIONS_AUTOCORRECT	Autocorrect invalid cells if possible
3	ATM_CFG_OPTIONS_IMA_BUNDLE	Configuration describes an IMA bundle

Note: Either Payload Scrambling or ATM Coset mode, or both, must be enabled for correct operation. Configurations which disable both options will be rejected.

•ima frame length

The length of the IMA frame.

Value	Mnemonic	Description
1	ATM_CFG_IMA_FRAME_32	32 cells per IMA frame
2	ATM_CFG_IMA_FRAME_64	64 cells per IMA frame
3	ATM_CFG_IMA_FRAME_128	128 cells per IMA frame
4	ATM_CFG_IMA_FRAME_256	256 cells per IMA frame

Note: For non IMA streams this field is reserved and should be set to zero.

•max frame length

The maximum length of a reassembled (AAL) frame. Frames longer than this will be discarded by the ATM layer.

Note: The maximum AAL frame length accepted at the ATM layer is determined by the requirements of the full protocol stack. At present, the requirements of the MTP3 layer and above are support for signaling units with a SIF length of less than or equal to 272 octets. MTP3-b (and subsequently Q.2140 / Q.2110) allow frames of up to 4K octets. In keeping with the current behavior of the protocol stack, if a peer sends a data frame longer than the maximum frame length parameter, the ATM layer will consistently discard the frame (and all retransmissions); hence the Q.SAAL link will be taken out of service. This is to ensure any data acknowledged by the Q.SAAL signaling link can be passed to the user application intact.

•default vpi

A default AAL5 link will be configured for the cell stream to signal incoming active connections. This is the VPI that will be used for this connection. The VPI must be available in the mask configured in the ATM_MSG_CONFIG message.

•default vci

A default AAL5 link will be configured for the cell stream to signal incoming active connections. This is the VCI that will be used for this connection. Values 0, 3, and 4 are reserved and should not be used and the VCI value must be viable in the mask specified in the ATM_MSG_CONFIG message.

Note: The default VPI/VCI combination configured here must not be specified for any AAL5 link on this cell stream.

•tdm stream

TDM streams to be used by the cell stream.

If IMA is active, the parameter is a bitmap of the TDMs to be used by the bundle (bit 0 = TDM 0, etc.). If IMA is not active, the parameter identifies the TDM to be used.

•tdm timeslot

Bitmap of active timeslots within the above TDM streams.

The timeslots are dependent on the LIU configuration. Typically, the timeslot bitmap for E1 will be 0xfffefffe and for T1/J1 will be 0x01fffffe.

81