CN8236EBGB Mindspeed Technologies, CN8236EBGB Datasheet - Page 117

• Manufacturer Part Number: CN8236EBGB
• Description: ATM SAR 155Mbps 3.3V ABR/CBR/GFR/UBR/VBR 388-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of CN8236EBGB

• Package: 388BGA
• Traffic Class: ABR|CBR|GFR|UBR|VBR
• Utopia Type: Level 1|Level 2
• Host Interface: PCI
• Maximum Data Rate: 155 Mbps
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3 V

CN8236
ATM ServiceSAR Plus with xBR Traffic Management
Figure 5-5. Direct Index Lookup Method for AAL3/4
28236-DSH-001-B
5.2.2.4 AAL3/4 Lookup
Base Register (16)
RSM_TBASE
(RSM_ITB)
VPI [11:0]
VPI Index Table
VCI_IT_PNTR
VC_EN is a logic low, the cell is discarded, and the CELL_DSC_CNT counter is
incremented. Optionally, the counter is not incremented if the AAL_TYPE field
has a value of 11. VC_EN allows idle cells to be filtered if the PHY layer has not
already done so.
counter.
AAL3/4 MID multiplexing requires an additional level of indirection in channel
lookup for received AAL3/4 traffic. This is because one Virtual Connection can
have a multiple number of connectionless messages (like SMDS datagrams)
multiplexed onto that one received connection. Each of these long SDUs is
identified by its MID value. Thus, the VCC lookup also includes the MID value
in the lookup mechanism.
described in
VCC_BLOCK_INDEX + VCI[5:0] points to an AAL3/4 Head RSM VCC table
entry (see
to the first entry of a block of AAL3/4 entries for one Virtual Connection, with
the MID value = 0.
received cell’s Virtual Connection and MID. The AAL3/4 lookup mechanism is
illustrated in
The reassembly coprocessor reads the first word of the VCC table entry. If
If the channel is active, the CN8236 increments the CELL_RCVD_CNT
The VPI Index table and VCI Index table lookup is performed exactly as
The AAL3/4 Head entry contains the VCC_INDEX_BASE field which points
VCC_INDEX_BASE + MID points to the RSM VCC table entry for the
Mindspeed Technologies
Table
Section
VCI [15:x]
Figure
5-14).
5-5.
5.2.2.4. However, for AAL3/4 connections,
VCC_Block_Index
VCI Index Table
(for one VPI)
(RSM_VCCB)
RSM_TBASE
™
VCI [x-1:0]
(Mid=0)
5.2 Reassembly Functional Description
MID
5.0 Reassembly Coprocessor
VCC_INDEX_BASE
VCC Table Entries)
VCC Table entries
(Block of AAL3/4
Reassembly
(Block of 2 x
VCC Table
for 1 VC)
8236_023
5-7