Filter
Top Products
S/UNI-QUAD
PMC-Sierra, Inc.
PM5349 S/UNI-QUAD
DATASHEET
PMC-971239 ISSUE 6 SATURN USER NETWORK INTERFACE (155-QUAD)
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
204
H4: The multiframe indicator byte is a payload specific byte, and is not
used for ATM payloads.
13.2
ATM Cell Data Structure
ATM cells may be passed to/from the S/UNI-QUAD using a twenty-seven word,
16-bit Utopia level 2 compliant data structure. This data structure is shown in
Figure 12.
Figure 12: 16-bit Wide, 27 Word ATM Cell Structure
Bit 15 Bit 0
H1 H2
H3 H4
HCS
STATUS/CONTROL
H5
PAYLOAD1 PAYLOAD2
Bit 8 Bit 7
PAYLOAD3 PAYLOAD4
PAYLOAD5 PAYLOAD6
Word 1
Word 2
Word 3
Word 4
Word 5
Word 6
PAYLOAD47 PAYLOAD48
Word 27
Bit 15 of each word is the most significant bit (which corresponds to the first bit
transmitted or received). The header check sequence octet (HCS) is passed
through this structure. The start of cell indication input and output (TSOC and
RSOC) are coincident with Word 1 (containing the first two header octets). Word
3 of this structure contains the HCS octet in bits 15 to 8.
In the receive direction, the lower 8 bits of Word 3 contain the HCS status octet.
An all-zeros pattern in these 8 bits indicates that the associated header is error