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The top half of the number blinks if the switch is the master, and the bottom half blinks if it is the

backup. If the LED is steadily lit, the switch is a standby. If the LED is o the switch is not conﬁgured as a

member of a stack.

The Mode button is used to cycle through three display modes for the port LEDs. After two presses of

the Mode button, the port LEDs will enter the STK Display Mode, indicated by the STK LED. STK mode is

used to indicate slot presence and slot number via the ﬁrst eight port LEDs.

Figure 36: Mode Button with STK LED Example

The LED is steady green if the link is OK, blinking green if trac is present, and o if no signal is present.

A quick way to verify that the cable connections match the software conﬁguration is to check the stack

number indicator on each switch. If the slot numbers do not line up in the order you arranged the

switches, this might indicate that the stacking cable setup diers from what you intended when you

conﬁgured the software. In this case, reconnect the cables in the correct order and perform the

software conﬁguration again.

Master/Backup Switch Redundancy

When your stack is operational, one switch is the master switch, responsible for running network

protocols and managing the stack.

To provide recovery in case of a break in the stack connections, you can conﬁgure redundancy by

designating a backup switch to take over as master if the master switch fails. When you perform the

initial software conﬁguration of the stack, the “easy setup” conﬁguration option automatically

conﬁgures redundancy, with slot 1 as the master and slot 2 as the backup. You can also conﬁgure

additional switches as “master-capable,” meaning they can become a stack master in case the initial

backup switch fails.

When assigning the master and backup roles in mixed stacks, consider the feature scalability and the

speed of each switch model. The easy setup conﬁguration process selects master and backup switches,

based on capability and speed, in the following order:

1. X690, and X870

2. X670-G2 and X465

3. 5520 and X460-G2

4. X450-G2

5. X440-G2 and X620

For example, in a stack that combines X460-G2 or X670-G2 switches with other switch models, an

X460-G2 or X670-G2 switch might provide more memory and more features than other switches in the

Building Basic Stacks

Building Stacks

54 ExtremeSwitching 5520 Series Hardware Installation Guide

Extreme Networks ExtremeSwitching 5520-48T User Manual

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