Dell PowerConnect 3548 User Manual

14 Introduction
The device units are shipped with a default Unit ID of the stand-alone unit. If the device is operating as
a stand-alone unit, all stacking LEDs are off.
Once the user selects a different Unit ID, it is not erased, and remains valid, even if the unit is reset.
Unit ID 1 and Unit ID 2 are reserved for Master enabled units. Unit IDs 3 to 8 can be defined for stack
members.
When the Master unit boots or when inserting or removing a stack member, the Master unit initiates
a stacking discovering process.
NOTE: If two members are discovered with the same Unit ID the stack continues to function, however only the unit
with the older join time joins the stack. A message is sent to the user, notifying that a unit failed to join the stack.
Removing and Replacing Stacking Members
Unit 1 and Unit 2 are Master enabled units. Unit 1 and Unit 2 are either designated as Master Unit or
Backup Master Unit. The stack Master assignment is performed during the configuration process.
One Master enabled stack member is elected as Master, and the other Master enabled stack member is
elected as Backup Master, according to the following decision process:
• If only one Stack Master enabled unit is present, it is elected as the Master.
• If two Master enabled stacking members are present, and one has been manually configured as the
Stack Master, the manually configured member is elected as Stack Master.
• If two Master enabled units are present and neither has been manually configured as the Master, the
one with the longer up-time is elected as the Stack Master.
• If two Master enabled units are present and both have been manually configured as the Master, the one
with the longer up-time is elected as the Stack Master.
• If the two Master enabled stacking members are the same age, Unit 1 is elected as the Stack Master.
NOTE: Two stacking member are considered the same age if they were inserted within a ten minute interval.
For example, Unit 2 is inserted in the first minute of a ten-minute cycle, and Unit 1 is inserted in fifth
minute of the same cycle, the units are considered to be the same age. If there are two Master enabled
stack members that are the same age, then Unit 1 is elected master.
The Stack Master and the Backup Master maintain a Warm Standby. The Warm Standby ensures that
the Backup Master takes over for the Stack Master if a failover occurs. This guarantees that the stack
continues to operate normally.
During the Warm Standby, the Master and the Backup Master are synchronized with the static
configuration only. When the Stacking Master is configured, the Stack Master must synchronize the
Stacking Backup Master. The Dynamic configuration is not saved, for example, dynamically learned
MAC addresses are not saved.

Dell PowerConnect 3548 Specifications

General

MAC address table	8000 entries
Maximum data transfer rate	0.1 Gbit/s
Supported data transfer rates	10/100 Mbps
10G support	-
Number of VLANs	256
Flow control support	Yes
Networking standards	IEEE 802.1D, IEEE 802.1p, IEEE 802.1Q, IEEE 802.1s, IEEE 802.1w, IEEE 802.3ad
Dimensions (WxDxH)	440 x 257 x 43.2 mm
Networking features	Gigabit Ethernet, Fast Ethernet
Authentication method	RADIUS, TACACS+
Connectivity technology	Wired
Switch type	Managed
Switch layer	L2
Data link protocols	Ethernet
Supported network protocols	HTTP, HTTPS/SSL, SSH
Power connector	DC-in jack
SFP/SFP+ slots quantity	2
Basic switching RJ-45 Ethernet ports quantity	48
Product color	Black
Storage temperature (T-T)	-20 - 70 °C
Operating temperature (T-T)	0 - 45 °C
Storage relative humidity (H-H)	10 - 95 %
Operating relative humidity (H-H)	10 - 90 %

Weight and Dimensions

Weight	8000 g