Technical data

Brocade MLX Series and NetIron Family Documentation Updates 53

53-1002805-03

STP feature configuration

• You cannot add a subset of the ports in a trunk group to the Fast Uplink Span group. All ports

in a trunk group have the same Fast Uplink Span property, as they do for other port properties.

• If the working trunk group is partially down but not completely down, no switch-over to the

backup occurs. This behavior is the same as in the standard STP feature.

• If the working trunk group is completely down, a backup trunk group can go through an

accelerated transition only if the following are true:

• The trunk group is included in the fast uplink group.

• All other ports except those in this trunk group are either disabled or blocked. The

accelerated transition applies to all ports in this trunk group.

When the original working trunk group comes back (partially or fully), the transition back to the

original topology is accelerated if the conditions listed above are met.

Configuring a Fast Uplink Port Group

To configure a group of ports for Fast Uplink Span, enter the following commands:

Brocade(config)# fast uplink-span ethernet 4/1 to 4/4

Brocade(config)# write memory

Syntax: [no] fast uplink-span [ethernet <port> [ethernet <port>… | to <port>]]

Specify the port variable in one of the following formats:

• FWS, FCX, and ICX stackable switches – stack-unit/slotnum/portnum

• FSX 800 and FSX 1600 chassis devices – slotnum/portnum

• ICX devices – slotnum/portnum

• FESX compact switches – portnum

This example configures four ports, 4/1 – 4/4, as a Fast Uplink Span group. In this example, all

four ports are connected to a wiring closet switch. Only one of the links is expected to be active at

any time. The other links are redundant. For example, if the link on port 4/1 is the active link on

the wiring closet switch but becomes unavailable, one of the other links takes over. Because the

ports are configured in a Fast Uplink Span group, the STP convergence takes one second instead of

taking atleast 30 seconds using the standard STP forward delay.

You can add ports to a Fast Uplink Span group by entering the fast uplink-span command

additional times with additional ports. The device can have only one Fast Uplink Span group, so all

the ports you identify as Fast Uplink Span ports are members of the same group.

To remove a Fast Uplink Span group or to remove individual ports from a group, use “no” in front of

the appropriate fast uplink-span command. For example, to remove ports 4/3 and 4/4 from the

Fast Uplink Span group configured above, enter the following commands:

Brocade(config)# no fast uplink-span ethernet 4/3 to 4/4

Brocade(config)# write memory

To check the status of ports with Fast Uplink Span enabled.

Brocade(config)# show span fast-uplink-span

STP instance owned by VLAN 1

Global STP (IEEE 802.1D) Parameters:

VLAN Root Root Root Prio Max He- Ho- Fwd Last Chg Bridge