參數(shù)資料
型號: MT90500
廠商: Mitel Networks Corporation
英文描述: Multi-Channel ATM AAL1 SAR(多通道 ATM AAL1分段及重組設(shè)備(基于通訊總線的系統(tǒng)與ATM網(wǎng)絡(luò)的接口))
中文描述: 多通道自動柜員機AAL1特區(qū)(多通道自動柜員機AAL1分段及重組設(shè)備(基于通訊總線的系統(tǒng)與空中交通管理網(wǎng)絡(luò)的接口))
文件頁數(shù): 152/159頁
文件大?。?/td> 514K
代理商: MT90500
MT90500
152
ATM Receive Process Bandwidth
A. Access to VC Look-up Table.
Assuming an overall inbound traffic rate of 25.6 Mbps, the External Memory to Internal TDM Memory Structure
encounters a maximum of ~60,000 cells per second (i.e. (3.2 Mbytes/s) / (53 bytes/cell) = 60377.36 cells / s).
Assuming an overall inbound traffic of 155.52 Mbps (again, 1M = 1 000 000), the External Memory to Internal
TDM Memory Structure encounters ~400,000 cells per second (i.e. (19.44 Mbytes/s) / (53 bytes/cell) =
366792.45 cells / s). There is one double-word read access per cell.
25.6 Mbps
~ 0.06 M accesses / s
155.52 Mbps
~ 0.4 M accesses / s
B. RX_SAR Control Structure Accesses.
Each received cell requires three control double-word read accesses (for the twelve bytes of control data at the
start of each RX_SAR Control Structure), one control double-word write access (to update the Current Entry
and TDM Write Pointer fields of the RX_SAR Control Structure), as well as up to 24 double-word read accesses
(to select up to 48 RX Circular Buffer Base Addresses per cell) to know which data to transfer, for a total of up
to 28 memory accesses per cell transmitted. 256 TDM channels represent a rate of ~ 5.5 cells / 125
μ
s; 512
TDM channels represent a rate of ~11 cells / 125
μ
s; etc.
28 double-word read accesses * estimated cell arrival rate (per 125
μ
s) = 224000 * cell arrival rate.
256 TDM channels
1.232 M accesses / s
512 TDM channels
2.464 M accesses / s
1024 TDM channels
4.928 M accesses / s
C. Access to the Receive Circular Buffers.
One double-word (32-bit) read access followed by a double-word write access (to clear the underrun bit after
the byte has been read) per TDM channel every four frames (500
μ
s). Four times as many accesses are
required to transfer the data from the received cell to the circular buffer, byte per byte.
((1 double-word read access + 1 double-word write access + 4 half-word write accesses) / 500
μ
s * ‘N’
TDM channels = 12000 * ‘N’ accesses/s.
256 TDM channels
3.07 M accesses / s (5.63 M accesses / s)
512 TDM channels
6.14 M accesses / s (11.3 M accesses / s)
1024 TDM channels
12. 3 M accesses / s (22.5 M accesses / s)
D. Access to the External Memory to Internal TDM Memory Structure.
One double-word read access is required per TDM channel every 4 frames (500
μ
s):
(1 double-word read access / 500
μ
s) * ‘N’ TDM channels = 2000 * ‘N’ accesses/s.
256 TDM channels
512 TDM channels
1024 TDM channels
0.512 M accesses / s
1.024 M accesses / s
2.048 M accesses / s
Sub-total of external memory access bandwidth requirements to support the ATM to TDM receive
process:
Minimum requirements:
~ 7.76 M accesses / s
Maximum requirements:
~ 29.9 M accesses /s
Total Bandwidth Requirements
Total of external memory access bandwidth requirements to support both the TDM to ATM transmit and
the ATM to TDM receive process:
Minimum requirements:
~ 11.9 M accesses / s
Maximum requirements:
~ 46.3 M accesses /s
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MT90500AL 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:Multi-Channel ATM AAL1 SAR
MT90500AL-ENG1 制造商:Mitel Networks Corporation 功能描述:
MT90502 制造商:ZARLINK 制造商全稱:Zarlink Semiconductor Inc 功能描述:Multi-Channel AAL2 SAR
MT90502_06 制造商:ZARLINK 制造商全稱:Zarlink Semiconductor Inc 功能描述:Multi-Channel AAL2 SAR
MT90502AG 制造商:Rochester Electronics LLC 功能描述: 制造商:Zarlink Semiconductor Inc 功能描述: