- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄382907 > COMMPROCWP Communications Processors: A Definition and Comparison PDF資料下載
參數(shù)資料
| 型號： | COMMPROCWP |
| 英文描述： | Communications Processors: A Definition and Comparison |
| 中文描述： | 通訊處理器：定義和比較 |
| 文件頁數(shù)： | 5/8頁 |
| 文件大?。?/td> | 413K |
| 代理商： | COMMPROCWP |
May 3, 2000
Network System Design Alternatives
5
remains essentially in hardware. In addition, having a single
software-capable CPU element limits both performance
and programmability.
Configurable Processor Cores
Configurable processor cores embedded in an ASIC design
allow customization of the instruction set. In networking
applications, this may allow the designer to create
specialized instructions for certain communications tasks,
such as the implementation of specific software encryption
algorithms. However, such architectures assume that the
software is handling the data and thus the processor must
be inserted in the primary data path. This approach does
not scale and has been the main reason discrete
CPU-oriented systems have failed to keep pace in the past.
Moreover, this approach also does not address the
fundamental bottleneck in “soft” architectures
—
separating the control path from the data path in an
effective and scalable way.
Both the configurable “systems-on-a-chip” and
configurable processor cores are variations on the custom
chip theme, and suffer in varying degrees the limitations
described above for ASIC-based approaches. In particular,
these methods do not address maximizing software re-use
as the key to higher reliability, faster time-to-market,
increased product lifespan, and the delivery of expanded
network services.
Application-Specific Standard Products
Most communications system designs, whether based on
CPU or ASIC architectures, make use of some specialized
components. These are often used where a specific function
is difficult to build into an ASIC, is available in a low cost
off-the-shelf component, or is not central to the system
design. An example of an ASSP-based design is shown in
Figure 3. Some silicon vendors have continued to make
standalone ASSPs attractive by supplying increasing
functional density, such as has occurred with low-speed
framers and physical interfaces (transceivers).
Smart MACs
Communications IC vendors have also been working to
make some components smarter, integrating more and
more of the functions that would normally be handled by a
CPU and software (or in hardware with a custom ASIC) into
the component.
For example, some makers of Ethernet MAC ICs have begun
incorporating some protocol data parsing and processing
functions within the interface, alleviating some of the
lower-level tasks from the system software. This can be
beneficial for certain classes of products (such as network
interface cards, for example), but is really only a small
incremental improvement over traditional design
methodologies for mainstream communication systems.
Single-Function Components
A different approach has been taken by other vendors who
have set out to design optimized components addressing a
single, higher-level function within the system. Examples
include IP address lookup engines and traffic classifiers.
These components reduce the number of functions the
system designer must implement in custom ASICs and
subsequently reduce time-to-market. Some of these
components also represent the state-of-art for a particular
function, increasing the capability of the system solution.
However, systems based on these devices still suffer from
the limitations of a hardware-oriented approach. The
configurability provided in the components is usually only
enough to support the specific design, but not enough to
adapt to emerging customer requirements or standards.
Higher-level services, which must be implemented in
software, are also limited (if not prevented) by this
approach.
Perhaps the biggest obstacle to single-function
components is the level of effort required to effectively
integrate various components into a complete system. For
the higher bandwidth interfaces (like Gigabit Ethernet,
OC-12, and OC-48), the interconnect design between
components is often the primary system bottleneck.
Multiple components lead to more complex hardware
designs, less scalability, and increased time-to-market.
Programmable Communications Components
There are classes of communications-focused ICs with
programmability similar to Network Processors. No matter
how programmable a specific component may be, however,
it is still limited by the overall system design issues of
integrating various independent components. See Figure 5.
Digital Signal Processors
Digital Signal Processors (DSPs) offer a great deal of
flexibility in the implementation of signal processing
algorithms for a wide range of physical layer applications
such as high-speed modems. With custom instruction sets
for fixed and floating point arithmetic, DSPs are optimized
for the mathematically intensive algorithms used in
advanced signal processing.
F
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| COMP | Analog IC |
| CONFERENCEPAPERREPRINT | Conference Paper Reprint - Multimedia over FDDI (Paper) |
| CONFIGURE | Configure Low-Cost Buck Controller for Boost Operation (21k) |
| CONFIGURING | Configuring the ?lanSC300 Device＇s Internal CGA Controller for a Specific LCD Panel Application Note? 277KB (PDF) |
| CONTROLINTEGRATEDCIRCUITS | Control Integrated Circuits(22.16 k) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| COMM-THKWL-HST-WOS-.400\-X | 制造商:TE Connectivity 功能描述: |
| COMM-THKWL-HST-WOS-.400-X- | 制造商:TE Connectivity 功能描述: |
| COMM-THKWL-HST-WOS-.750\-X | 制造商:TE Connectivity 功能描述: |
| COMM-THKWL-HST-WOS-.750-X- | 制造商:TE Connectivity 功能描述: |
| COMM-THKWL-HST-WOS-1.10\\-X | 制造商:TE Connectivity 功能描述: |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。