3Com 4005, Installation And Maintenance Manual

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14 C
HAPTER
2: O
VERVIEW OF THE
S
WITCH
4005
Switch Backplane
Architecture
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
■
Passive design, meaning that there are no active components that can fail
■
Support for dual, redundant Switch Fabric Management Modules (SFMMs)
■
Support for system communication between the SFMM and interface modules
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
■
a control channel that passes signals for module detection
■
module diagnostics
■
LED operation between the SFMM and interface modules
■
a Serial Communication Interface (SCI) communications channel that operates
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.
Gigabit
Data
Traces
SCI
Swithc
Fabric
&
Management
Slot
M1
UART
Control
Traces
Interface
Slot
1
Interface
Slot
2
Interface
Slot
3
Interface
Slot
4
Interface
Slot
5
Interface
Slot
6
Interface
Slot
7
Interface
Slot
8
Interface
Slot
9
Interface
Slot
10
Interface
Slot
11
Interface
Slot
12
Swithc
Fabric
&
Management
Slot
M2