ForeRunner ATM Switch Network Configuration Manual
9 - 1
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CHAPTER 9
Configuring Timing
This chapter describes how to set up timing on a ForeRunner ATM Switch. Topics covered
include:
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9.1 Overview
For ATM networks to function well at full bandwidths, the equipment on the networks should
be timed so that they are all transmitting and receiving data in a synchronized manner. Even
though ATM is asynchronous, this only refers to the cell-level transmission that occurs in the
ATM Layer. The physical layer underlying the cells is synchronous. Therefore, a time reference
signal must be distributed to every element in the network to establish one cohesive entity.
This time reference on ForeRunner ATM Switches is called a switchclock.
9.2 Timing Modes
There are two timing modes available on ForeRunner ATM Switches: TCM and switch. TCM
mode means that all network modules that support distributed timing import their clock
source from the Timing Control Module (TCM).
NOTE
You must have a TCM installed in your switch in
order to use this timing mode. See the CEC-Plus
User’s Manual for information about configuring
timing with a TCM. All examples in this chapter
assume that you do not have a TCM installed.
Switch mode means that all network modules that support distributed timing import their
clock source from the designated switchclock port. This is the default mode for any switch
that does not have a TCM installed. See Section 9.3 for more information about this mode.
Summary of Contents for forerunner series
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Page 16: ...TOC 10 ForeRunner ATM Switch Network Configuration Manual Table of Contents ...
Page 20: ...LOF 4 ForeRunner ATM Switch Network Configuration Manual List of Figures ...
Page 22: ...LOT 2 ForeRunner ATM Switch Network Configuration Manual List of Tables ...
Page 30: ...viii ForeRunner ATM Switch Network Configuration Manual Preface ...
Page 144: ...3 58 ForeRunner ATM Switch Network Configuration Manual Configuring an Emulated LAN ...
Page 180: ...6 12 ForeRunner ATM Switch Network Configuration Manual ATM Forum PNNI ...
Page 220: ...9 6 ForeRunner ATM Switch Network Configuration Manual Configuring Timing ...
Page 300: ...D 24 ForeRunner ATM Switch Network Configuration Manual Configuring FramePlus Modules ...
Page 308: ...Acronyms 8 ForeRunner ATM Switch Network Configuration Manual Acronyms ...
Page 346: ...Glossary 38 ForeRunner ATM Switch Network Configuration Manual Glossary ...
Page 352: ...Index 6 ForeRunner ATM Switch Network Configuration Manual Index ...