Example Network Configuration Steps - Alcatel OmniSwitch 6624 Network Configuration Manual

Configuring Spanning Tree Parameters
VLAN 255 on Switch D is configured with a Bridge ID priority value of 10, which is less than the
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same value for VLAN 255 configured on the other switches. As a result, VLAN 255 was elected the
Spanning Tree root bridge for the VLAN 255 broadcast domain.
A root port is identified for VLAN 255 on each switch, except the root VLAN 255 switch. The root
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port identifies the port that provides the best path to the root VLAN.
VLAN 255 on Switch A was elected the designated bridge because it offers the best path cost for
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Switch B to the root VLAN 255 on Switch D.
Port 2/9 on Switch A is the designated port for the Switch A to Switch B connection because Switch A
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is the designated bridge for Switch B.
Redundant connections exist between Switch D and Switch C. Ports 2/2 and 3/9 are in a discarding
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(blocking) state because this connection has a higher path cost than the connection provided through
ports 2/3 and 3/8. As a result, a network loop condition is avoided.
Redundant connections also exist between Switch A and Switch B. Although the path cost value for
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both of these connections is the same, ports 2/8 and 3/3 are in a discarding state because their port
priority values (not shown) are higher than the same values for ports 2/10 and 3/1.
The ports that provide the connection between Switch B and Switch C are in a discarding (blocking)
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state, because this connection has a higher path cost than the other connections leading to the root
VLAN 255 on Switch D. As a result, a network loop is avoided.

Example Network Configuration Steps

The following steps provide a quick tutorial that configures the active Spanning Tree network topology
shown in the diagram on
1 Create VLAN 255 on Switches A, B, C, and D with "Marketing IP Network" for the VLAN descrip-
tion on each switch using the following command:
-> vlan 255 name "Marketing IP Network"
2
Assign the switch ports that provide connections between each switch to VLAN 255. For example, the
following commands entered on Switches A, B, C, and D, respectively, assign the ports shown in the
example network diagram on
-> vlan 255 port default 2/8-10
-> vlan 255 port default 3/1-3
-> vlan 255 port default 3/8-10
-> vlan 255 port default 2/1-3
3
Change the Spanning Tree protocol for VLAN 255 to 802.1w (rapid reconfiguration) on each switch
using the following command:
-> bridge 255 protocol 1w
4 Change the bridge priority value for VLAN 255 on Switch D to 10 using the following command
(leave the priority for VLAN 255 on the other three switches set to the default value of 32768):
-> bridge 255 priority 10
VLAN 255 on Switch D will have the lowest Bridge ID priority value of all four switches, which will
qualify it as the Spanning Tree root VLAN for the VLAN 255 broadcast domain.
OmniSwitch 6624/6648 Network Configuration Guide
page 5-20.
page 5-20 to VLAN 255:
Sample Spanning Tree Configuration
April 2004 page 5-21