CHAPTER 1
ERX System Overview
Where the ERX System Fits In
Figure 1-5 and Figure 1-6 illustrate the position of the system as an edge router in an end-to-end Internet network. Communications with the system can take place over a variety of media. In Figure 1-5, the customers are businesses using T1/T3 communication lines. In
Figure 1-6, the customers are using digital subscriber lines (DSLs) with a DSL access multiplexer (DSLAM).
Remote |
| Internet | |
| Remote | ||
access |
| ||
ERX system | access router | ||
router | |||
| OC3 | ||
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Hub | T1/T3 | Core router | Hub |
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Desktop
Desktop 
Figure 1-5 ERX system communicating over T1/T3 lines
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| ERX system | Core | Remote |
Home office |
| router | access router | |
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| |||
|
| OC3 |
| |
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| DS3 |
| |
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| |
| DSLAM |
| Internet | Hub |
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Desktop 
