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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Network Processor
Engines (NPE)
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
222
Order Number: 306262-004US
4.0
Network Processor Engines (NPE)
The Network Processor Engines (NPE) are dedicated function processors containing
hardware coprocessors that are integrated into the Intel
®
IXP45X and Intel
®
IXP46X
Product Line of Network Processors. The NPEs are used to offload processing functions
required by the Intel XScale
®
Processor.
The NPEs are high-performance, hardware multi-threaded processors with additional
local hardware assist functionality used to off load processor intensive functions such as
MII (MAC), CRC checking/generation, AAL2, DES, AES, SHA, MD5, etc.
Note:
Certain NPEs are not available, depending on which variant of the IXP45X/IXP46X
network processors is used.
shows which network-processor models have
which NPEs enabled.
All instruction code for the NPEs is stored locally through a dedicated instruction
memory bus and dedicated data memory bus. The NPE’s support processing of
dedicated peripherals interfaces on the IXP45X/IXP46X network processors. The
peripherals supported by the use of the NPEs are up to three SMII interfaces, up to
three MII interfaces, UTOPIA Level 2 interface, and two high-speed serial interfaces.
The NPE core is a hardware multi-threaded processor engine that is used to accelerate
functions that are difficult to achieve high performance in a standard RISC processor.
Each NPE core is a 133-MHz processor core that has self-contained instruction memory
and self-contained data memory that operate in parallel.
In addition to having separate instruction/data memory, the NPE core supports
hardware multi-threading with support for multiple contexts. The support of hardware
multi-threading allows an efficient processor engine with minimal processor stalls due
to the ability of the processor core to switch context to a new context in a single clock
cycle based upon a prioritized/preemptive basis.
The prioritized/preemptive nature of the context switching allows time critical
applications to be implemented in a low-latency fashion, which is required when
processing multi-media applications. The NPE core also connects several hardware-
based coprocessors. The coprocessors are used to implement several functions that are
difficult for a processor to implement. The type of functions implemented by the
coprocessors are serialization/de-serialization, CRC checking/generation, DES/3DES,
AES, SHA, MD-5, and HDLC bit-stuffing/de-stuffing. These coprocessors are
implemented in hardware, therefore allowing the coprocessors and the Network
Processor Engine core to operate in parallel.
Table 97.
Processors: Network Processor Functions
Device
NPEA
NPEB
NPEC
UTOPIA
HSS
HDLC
ETHA
ETHB1
ETHB2
ETHB3
ETHB4
ETHC
AES/DES/SHA/MD5
Intel
®
IXP465
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Intel
®
IXP460
NO
NO
NO
NO
YES
NO
NO
NO
YES
NO
Intel
®
IXP455
YES
YES
YES
YES
YES
NO
NO
NO
YES
YES