tdat04622 ETC-unknow, tdat04622 Datasheet - Page 114

• Manufacturer Part Number: tdat04622
• Description: Tdat Sonet/sdh 155/622/2488 Mbits/s Data Interfaces
• Manufacturer: ETC-unknow

TDAT042G5 SONET/SDH
155/622/2488 Mbits/s Data Interface
Functional Description
UTOPIA (UT) Interface Block
UTOPIA ATM Cell Processing
The UTOPIA block will process ATM packets of 52, 53, 54, or 56 bytes. The standard 53-byte ATM cell structure is
shown in Table 25.
Table 25. Standard 53-byte ATM Cell Structure
In the receive path, TDAT042G5 automatically calculates the HEC (byte 5) and overwrites this byte of the ATM cell.
It is therefore possible to transfer only 52-byte packets through the UTOPIA I/O to increase interface efficiency.
This mode will be referred to as the 52-byte mode. The 52-byte or 53-byte ATM mode is provisioned through
ATM_SIZE_Rx[A—D] (bit 4 of registers 0x020F, 0x0213, 0x0217, and 0x021B) and ATM_SIZE_Tx[A—D]
registers 0x0210, 0x0214, 0x0218, and 0x021C).
U2 Modes. For U2 and U2+, both the 52-byte and 53-byte, 16-bit UTOPIA interface modes are supported for ATM
cells as shown in Table 26.
Table 26. Bus Format for 16-bit Interface
* UDF refers to the undefined H5 byte.
† This option is also called the 54-byte mode.
86
TxD[15:8] or RxD[15:8]
8 bits
H1
H5 (HEC)
D47
H1
H3
D1
D3
.
.
.
8 bits
53-byte Option
H2
TxD[7:0] or RxD[7:0]
8 bits
H3
H5 (UDF*)
†
(continued)
D48
H2
H4
D2
D4
(continued)
.
.
.
8 bits
H4
TxD[15:8] or RxD[15:8]
53 bytes
H5 (HEC)
8 bits
52-byte Option (HEC Omitted)
D47
H1
H3
D1
D3
.
.
.
8 bits
D1
TxD[7:0] or RxD[7:0]
8 bits
D2
D48
H2
H4
D2
D4
.
.
.
. . .
Agere Systems Inc.
Data Sheet
May 2001
8 bits
(
D48
bit 4 of