Switch Backplane Architecture - 3Com 4005 Installation And Maintenance Manual

14 C 2: O
HAPTER VERVIEW OF THE
Switch Backplane
Architecture
Gigabit
Data
Traces
UART
Control
Traces
S 4005
WITCH
A star-wired scheme of traces inside the chassis, which is called the backplane, is
used to connect each interface module slot to the Switch Fabric Management
Module (SFMM) slots. A module, fan tray, or power supply connects to the
backplane when it is inserted into a slot and its connectors engage the connectors
that are inside the chassis.
As shown in Figure 3, the Switch 4005 backplane design offers:
12 Gbps of non-blocking bandwidth capacity
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Passive design, meaning that there are no active components that can fail
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Support for dual, redundant Switch Fabric Management Modules (SFMMs)
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Support for system communication between the SFMM and interface modules
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for control signals, detection, and other management activities.
Figure 3 Backplane Architecture of the Switch 4005
The backplane connector on each module provides easy access to all the services
from the Switch 4005 backplane:
a data channel for network traffic between the SFMM and interface modules
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a control channel that passes signals for module detection
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module diagnostics
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LED operation between the SFMM and interface modules
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a Serial Communication Interface (SCI) communications channel that operates
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between two SFMMs (if installed) to keep their configurations synchronized
Traffic between ports on the same interface module does not enter the backplane;
that is, the interface modules provide layer 2 and layer 3 switching when the
packet's destination is a locally attached node. Interface modules send packets
that have non-local destination addresses across the backplane to the SFMM
which then switches the packets to the appropriate interface module.
SCI