Network Processor Engines (Npe); Processors: Network Processor Functions - Intel IXP45X Developer's Manual

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Network Processor Engines (NPE)

The Network Processor Engines (NPE) are dedicated function processors containing
hardware coprocessors that are integrated into the Intel
Product Line of Network Processors. The NPEs are used to offload processing functions
required by the Intel XScale
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.
which NPEs enabled.
Table 97.

Processors: Network Processor Functions

Device
UTOPIA
®
Intel IXP465 YES
®
Intel IXP460 NO
®
Intel IXP455 YES
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.
® ®
Intel IXP45X and Intel IXP46X Product Line of Network Processors
Developer's Manual
222
® ®
Intel IXP45X and Intel
®
Processor.
Table 97
NPEA
HSS HDLC ETHA ETHB1
YES YES YES
NO NO NO
YES YES YES
IXP46X Product Line of Network Processors—Network Processor
shows which network-processor models have
NPEB
ETHB2 ETHB3
YES YES YES
YES NO NO
YES NO NO
Engines (NPE)
® ®
IXP45X and Intel
NPEC
ETHB4 ETHC AES/DES/SHA/MD5
YES YES YES
NO YES
NO YES YES
Order Number: 306262-004US
IXP46X
NO
August 2006