XRT74L73 Datasheet, PDF (150/488 Pages) Exar Corporation – 3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER

XRT74L73
3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER
REV. P1.0.1
RxCP User Filter Cell Mask Header—Byte 2 (Address = 5Dh)
BIT 7
R/W
1
BIT 6
R/W
1
BIT 5
R/W
1
BIT 4
R/W
1
BIT 3
R/W
1
BIT 2
R/W
1
PRELIMINARY
BIT 1
R/W
1
BIT 0
R/W
1
RxCP User Filter Cell Mask Header—Byte 3 (Address = 5Eh)
BIT 7
R/W
1
BIT 6
R/W
1
BIT 5
R/W
1
BIT 4
BIT 3
RxUser Cell Mask Header—Byte 3
R/W
R/W
1
1
BIT 2
R/W
1
BIT 1
R/W
1
BIT 0
R/W
1
RxCP User Filter Cell Mask Header—Byte 4 (Address = 5Fh)
BIT 7
R/W
1
BIT 6
R/W
1
BIT 5
R/W
1
BIT 4
BIT 3
RxUser Cell Mask Heade—Byte 4
R/W
R/W
1
1
BIT 2
R/W
1
BIT 1
R/W
1
BIT 0
R/W
1
3.3.2.4OAM Cell Processing
OAM (Operation Administration and Maintenance)
cells, are special cells that are generated by the “Lay-
er Management” entity (within the BISDN Reference
Model), and are typically used to carry maintenance
related information such as:
• Virtual Path Connection (VPC)/Virtual Circuit
Connection (VCC) failure reporting
• VPC/VCC continuity check information
• VPC/VCC continuity verification: OAM Cell
Loopback Testing
• VPC/VCC Performance Monitoring
OAM cells are identified and distinguished from User
cells by their specific cell header byte patterns. ATM
layer entities can typically use one of four types of
OAM cells. These types of OAM cells are listed below.
• F4—Segment
• F4—End to End
• F5—Segment
• F5—End to End
F4 type OAM cells usually carry maintenance related
information regarding a specific Virtual Path Connection
(VPC). Whereas F5 type OAM cells usually carry main-
tenance related regarding a specific Virtual Circuit
Connection (VCC). The header byte patterns of each
of these types of OAM cells is tabulated below.
TABLE 27: THE HEADER BYTE PATTERN FORMATS FOR THE VARIOUS TYPES OF OAM CELLS
OAM CELL
F4 End-to-End
F4 Segment
F5 End-to-End
F5 Segment
OCTET 1
0000aaaa
0000aaaa
0000aaaa
0000aaaa
OCTET 2
aaaa0000
aaaa0000
aaaazzzz
aaaazzzz
OCTET 3
00000000
00000000
zzzzzzzz
zzzzzzzz
OCTET 4
01000a0a
00110a0a
zzzz101a
zzzz100a
where: a—bit is available for use by the ATM layer entity
z—Any VCI value other than 0
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