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Chapter 1
Introduction And Overview
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Outline
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The Network Systems Problems
The Challenge
Hardware, Software, And Hybrids
Network Processor
The Network Systems Problems
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The Internet can accommodate arbitrary,
heterogeneous network
Data rates keep increasing
Protocols and applications keep evolving
System design is expensive, and
implementation and testing take too long
Special-purpose hardware designed for one
system cannot be reused
More Big Problems (We don’t know)
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New devices not yet designed
New communication systems not yet
designed / standardized
New speeds much faster than those in use
New protocols not yet designed /
standardized
New applications not yet designed /
standardized
The Challenge
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Find flexible, general technologies that
enable rapid, low-cost design and
manufacture of a variety of scalable, robust,
efficient network systems that run a variety of
existing and new protocols, perform a variety
of existing and new functions for a variety of
existing and new, higher-speed networks to
support a variety of existing and new
applications
Hardware, Software, And Hybrids
High Speed
（or Cost）
☻ASIC：Special-purpose hardware
★Hybrids：Network Processor
☺Software
Flexibility
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Network Processor
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Like ASIC designs
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Unlike ASIC designs
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A Network Processor can be programmed
Unlike a Conventional CPU
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More flexibility and Easier / faster to update and Less expensive
Like a Conventional CPU
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Speed
A Network Processor has been optimized for packet processing
Combines the speed advantages of a custom hardware design
and the flexibility of a software implementation
The Idea In A Nutshell
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Devise new hardware building blocks
Make them programmable
Include support for protocol processing and I/O
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General-purpose processor(s) for control tasks
Special-purpose processor(s) for packet processing and
table lookup
Include functional units for tasks such as checksum
computation
Integrate as much as possible onto one chip
QUESTION？
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