IBM BladeCenter - Page 144

A
B C
Port 1Port 1
Port 1Port 1
Port 1Port 1
Port 2Port 2
Port 2Port 2
Port 2Port 2
Port 3Port 3
Port 3Port 3
Port 3Port 3
LAN 1LAN 1
LAN 2LAN 2
LAN 3LAN 3
Bridge ID = 15Bridge ID = 15
Bridge ID = 30Bridge ID = 30
Port Cost = 19Port Cost = 19
Port Cost = 19Port Cost = 19
Port Cost = 19Port Cost = 19
Port Cost = 19Port Cost = 19
Port Cost =4Port Cost =4
Port Cost =4Port Cost =4
Port Cost =4Port Cost =4
Bridge ID = 20Bridge ID = 20
Note: In this example, only the default STP values are used.
A
B C
Port 1Port 1
Port 1Port 1
Port 1Port 1
Port 2Port 2
Port 2Port 2
Port 2Port 2
Port 3Port 3
Port 3Port 3
Port 3Port 3
LAN 1LAN 1
LAN 2LAN 2
LAN 3LAN 3
Blocked
Root BridgeRoot Bridge
Designated BridgeDesignated Bridge
Root PortRoot Port
Root PortRoot Port
Designated PortDesignated Port
Designated PortDesignated Port
The switch with the lowest bridge ID (switch A) was elected the root bridge, and the
ports were selected to give a high port cost between switches B and C.
126 IBM BladeCenter 4-Port Gb Ethernet Switch Module: Installation and User’s Guide