Digital Subscriber Line Access Multiplexer (DSLAM) Example Design

Digital Subscriber Line Access Multiplexer (DSLAM) Example Design
UINT inter_cell_gap: 16; // Shaped wheel slots, indicates port bandwidth
UINT last_cell_sent: 16; // Shaped wheel slot
// LongWord - 2
UINT current_WRR_count: 8;// Decrementing WRR count
UINT WRR_count: 8;// WRR weight assigned to this VC
UINT current_unshaped_VC_index: 16; // This is the unshaped VC index
currently
// being processed
// LongWord - 3:18
Unshaped_VC unshaped_VC[16];// 16 unshaped queues and its associated
weights
// LongWord - 19;//Intercellgap and Lastcellsent
Unshaped_VC unshaped_VC[16];// 16 unshaped queues and its associated
weights
// LongWord - 20:31
UINT port_unused_1[13];// For alignment
};
4.3.1.2 VC Table Entry
//////////////////////////////////////////////////////////////////////////////
// VC table entry
// 8 lw per entry * 4096 VCs * 4 = 131Kbytes
struct VC_Entry_ {
// LongWord - 0
UINT CRC_Residue: 32;// CRC-32 residue.
// LongWord - 1
UINT vc_unused_0: 16;// For alignment
UINT queue_threshold_lo: 8; // Cells
UINT num_cells_enqueued: 8;// Cells
// LongWord - 2
UINT entry_valid: 1;// Set to 0 if VC is not configured
UINT vc_unused_1: 7;// For alignment
UINT unshaped_q_position: 4;// Offset in port table’ "unshaped_VC" this VC
is located
UINT wheel_num: 2;// Totally 4 wheel-pairs.
UINT type: 2; // Shaped CBR, shaped VBR-rt, shaped VBR-nrt, unshaped
classes
UINT port_num: 8;// Physical port #
UINT queue_threshold_hi: 8; // Cells
// LongWord - 3
UINT last_SCR_cell_sent: 16;// Slot location in wheel
UINT current_MBS: 16;// Unused bits padding for alignment
// LongWord - 4
UINT last_PCR_cell_sent: 16;// Slot location in wheel
UINT PCR: 16; // Shaped Wheel slots
// LongWord - 5
UINT MBS: 16; // Cells
UINT SCR: 16; // Shaped Wheel slots
// LongWord - 6
UINT atm_header;// AAL5 header
// LongWord - 7
UINT vc_unused_2;// For alignment (being used for AAL5 Header)
Application Note 31