Nortel Ethernet Routing Switch 5500 Series Stack Configuration
59
Regardless of stack configuration, the following applies:
•
When power is applied to the stack the base unit initializes, typically
within sixty seconds, and the entire stack powers up as a single logical
unit.
•
A RS-232 communications cable can be attached to the console port of
any switch in the stack to establish a console connection.
•
A software upgrade can be performed on the stack from any switch using
the console interface, a Telnet session, the Web-based management
interface, or any SNMP-based management software.
•
The stack can be managed using a Telnet session, Web-based
management interface, or any SNMP-based management software
through any stack switch port.
•
When stacking two or more switches. use the three foot cascade
max-return cable (part number AL2018009) to complete the link from
the last unit in the stack to the base unit.
Redundant cascade stacking
The Nortel Ethernet Routing Switch 5500 Series allows a stack of up to 8
units into a dual-path cascade stack. If any single unit fails or if a cable is
accidently disconnected, other units in the stack remain operational without
interruption.
In addition to increasing bandwidth, the software uses the cables to provide
two paths between units. If one path breaks the data travels over the
remaining path with half the normal inter-switch bandwidth.
The following diagram shows an example of how a stack configuration
reacts to a failed connection in the stack configuration. In the illustrated
example, the following is occurring:
•
Unit 3 becomes non-operational due to a unit failure, cable
disconnection, or a loss of power.
•
Units 2 and 4, directly upstream and downstream from Unit 3, sense
the loss of link signals from unit 3. The software causes all the data to
traverse the remaining path.
•
The Cascade Down LED for Unit 2 and the Cascade Up LED for Unit 4
turn amber to indicate an error has been detected.
•
The remaining stack units continue to be connected.
Nortel Ethernet Routing Switch 5500 Series
Installation
NN47200-300
2.00
Standard
5.0
7 July 2006
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Nortel Networks Confidential
.
