RS8234EBGC Mindspeed Technologies, RS8234EBGC Datasheet - Page 108

• Manufacturer Part Number: RS8234EBGC
• Description: RS8234EBGC ATM XBR SAR
• Manufacturer: Mindspeed Technologies

5.0 Reassembly Coprocessor
5.2 Reassembly Functional Description
5.2.2 Channel Lookup
Figure 5-3. Direct Index Method for VPI/VCI Channel Lookup
5-4
Base Register (16)
RSM_TBASE
(RSM_ITB)
VPI [11:0]
VPI Index Table
VCI_IT_PNTR
The RS8234’s reassembly coprocessor implements a VPI/VCI Index Table
mechanism using direct index lookup in order to assign each cell to a virtual
channel, based on its VPI/VCI value. Each channel is thus identified by its
internally generated index value, the VCC_INDEX.
concatenated index values. It simplifies user channel assignment, provides
flexible provisioning for received traffic, and provides fast, consistent lookup
times regardless of the VPI/VCI values. In addition, using VPI/VCI table indexes
minimizes the memory impact in preallocating large numbers of channels by
requiring that only the VCI Index Table entries be preallocated instead of the
VCC Table entries.
This VPI/VCI Table Index mechanism dynamically maps VPI/VCIs to
Figure 5-3
Mindspeed Technologies
VCI [15:6]
illustrates the direct index channel lookup mechanism.
(Max. 1024 entries
VCC_Block_Index
VCI Index Table
for each VPI)
ATM ServiceSAR Plus with xBR Traffic Management
(for one VPI)
™
(RSM_VCCB)
RSM_TBASE
VCI [5:0]
VCC Table Entries)
28234-DSH-001-B
(Block of 64
VCC Table
RS8234
100074_024