
IDT Multicast
PES32NT24xG2 User Manual
17 - 6
January 30, 2013
Notes
A side-effect of modifying the address due to multicast overlay processing is that the ECRC associated
with the original TLP may not be correct for the new modified TLP. The PES32NT24xG2 supports ECRC
regeneration for multicast overlay.
1
Therefore, functions perform the following ECRC processing.
–
If multicast overlay processing is disabled, then no ECRC processing is performed as part of multi-
cast egress processing.
–
If a multicast TLP does not contain an ECRC, then no ECRC processing is performed as part of
multicast egress processing.
–
If a multicast TLP contains an ECRC and multicast overlay processing is enabled, then the
following actions are performed.
The ECRC of the original multicast TLP is checked while simultaneously the ECRC for the new
modified TLP is computed or “regenerated.” This is implemented in the same pipeline stage
such that there is virtually no possibility of silent data corruption (e.g., a TLP bit flip that does not
result in a computed ECRC error in the original or regenerated ECRC).
If no error is detected in the ECRC associated with the original TLP, then the modified TLP is
forwarded with the regenerated ECRC.
If an error is detected in the ECRC associated with the original TLP, then the modified TLP is
forwarded with inverted regenerated ECRC (i.e., the computed ECRC of the modified TLP is
inverted).
No errors are reported due to multicast egress processing.
Usage Restrictions
The switch does not support the following transparent multicast transfers. All other transfers are
allowed.
–
A multicast TLP received on a downstream port that is multicasted to the partition’s upstream port
must not contain an address that maps into the upstream port’s NT function or DMA function BAR
apertures.
–
A TLP that crosses partitions via the non-transparent bridge (NTB) must not fall into a multicast
window in the destination partition. The NT translation in the NT function must be programmed to
prevent this scenario. Breaking this rule produces undefined results.
Non-Transparent Multicast Operation
This section describes the switch’s non-transparent (NT) multicast. NT multicast allows TLPs received
by a port to be multicasted to one or more output ports located in other switch partitions.
NT multicast requires the presence of an NT function in the upstream port of the partition that receives
the TLP to be multicasted. A TLP received on any port of such partition may be NT multicasted.
–
NT Multicast operation requires that the Memory Access Enable (MAE) control be enabled in the
PCICMD register of the NT function that receives the multicast packet.
NT multicast is based on a proprietary implementation that resembles transparent multicast. In partic-
ular, the NT function contains a Multicast Capability Structure
2
as defined in the PCI Express Base Specifi-
cation. This capability structure allows configuration of a multicast range, segmentation of the range into
multicast windows, and association of these windows with multicast groups. Each group is associated with
a set of ports, located in other switch partitions, to which the multicast TLP is delivered.
Note: NT multicast is only supported for groups 0 to 3.
1.
Note that ECRC regeneration is not dependent on the setting of the ECRC Checking Enable (ECRCCE) or
ECRC Generation Enable (ECRCGE) bits in the AERCTL register of any of the port functions.
2.
The switch allows boot-time programming (e.g., via EEPROM) of the capability structure link list within each
function’s configuration space. In order to use multicast within a switch partition, the Multicast Capability Structure
must be linked in the capabilities list in the configuration space of all functions in the partition. The DMA function is
excluded as it does not contain a Multicast Capability Structure.
Содержание PCI Express 89HPES32NT24xG2
Страница 20: ...IDT Table of Contents PES32NT24xG2 User Manual x January 30 2013 Notes...
Страница 24: ...IDT List of Tables PES32NT24xG2 User Manual xiv January 30 2013 Notes...
Страница 28: ...IDT List of Figures PES32NT24xG2 User Manual xviii January 30 2013 Notes...
Страница 56: ...IDT PES32NT24xG2 Device Overview PES32NT24xG2 User Manual 1 20 January 30 2013 Notes...
Страница 100: ...IDT Switch Core PES32NT24xG2 User Manual 4 22 January 30 2013 Notes...
Страница 124: ...IDT Switch Partition and Port Configuration PES32NT24xG2 User Manual 5 24 January 30 2013 Notes...
Страница 128: ...IDT Failover PES32NT24xG2 User Manual 6 4 January 30 2013 Notes...
Страница 148: ...IDT Link Operation PES32NT24xG2 User Manual 7 20 January 30 2013 Notes...
Страница 164: ...IDT SerDes PES32NT24xG2 User Manual 8 16 January 30 2013 Notes...
Страница 170: ...IDT Power Management PES32NT24xG2 User Manual 9 6 January 30 2013 Notes...
Страница 196: ...IDT Transparent Switch Operation PES32NT24xG2 User Manual 10 26 January 30 2013 Notes...
Страница 244: ...IDT SMBus Interfaces PES32NT24xG2 User Manual 12 40 January 30 2013 Notes...
Страница 247: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 3 January 30 2013 Notes...
Страница 248: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 4 January 30 2013 Notes...
Страница 330: ...IDT Switch Events PES32NT24xG2 User Manual 16 6 January 30 2013 Notes...
Страница 342: ...IDT Multicast PES32NT24xG2 User Manual 17 12 January 30 2013 Notes...
Страница 344: ...IDT Temperature Sensor PES32NT24xG2 User Manual 18 2 January 30 2013 Notes...
Страница 384: ...IDT Register Organization PES32NT24xG2 User Manual 19 40 January 30 2013...
Страница 492: ...IDT Proprietary Port Specific Registers PES32NT24xG2 User Manual 21 44 January 30 2013 Notes...
Страница 588: ...IDT NT Endpoint Registers PES32NT24xG2 User Manual 22 96 January 30 2013 Notes...
Страница 710: ...IDT JTAG Boundary Scan PES32NT24xG2 User Manual 25 12 January 30 2013 Notes...
Страница 743: ...IDT Usage Models PES32NT24xG2 User Manual 26 33 January 30 2013 Notes...
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