Cisco Catalyst 2960-X Command Reference

spanning-tree extend system-id
To enable extended system identification, use the spanning-tree extend system-id command in global
configuration mode. To disable extended system identification, use the no form of this command.
spanning-tree extend system-id
no spanning-tree extend system-id
Syntax Description
This command has no arguments or keywords.
Command Default
The extended system ID is enabled.
Command Modes
Global configuration
Command History
ModificationRelease
This command was introduced.Cisco IOS 15.0(2)EX
Usage Guidelines
The spanning tree uses the extended system ID, the switch priority, and the allocated spanning-tree MAC
address to make the bridge ID unique for each VLAN or multiple spanning-tree instance. Because a switch
stack appears as a single switch to the rest of the network, all switches in the stack use the same bridge ID for
a given spanning tree. If the stack master fails, the stack members recalculate their bridge IDs of all running
spanning trees based on the new MAC address of the stack master.
Support for the extended system ID affects how you manually configure the root switch, the secondary root
switch, and the switch priority of a VLAN.
If your network consists of switches that do not support the extended system ID and switches that do support
it, it is unlikely that the switch with the extended system ID support will become the root switch. The extended
system ID increases the switch priority value every time the VLAN number is greater than the priority of the
connected switches.
Examples
This example shows how to enable the extended-system ID:
Switch(config)# spanning-tree extend system-id
Related Commands
DescriptionCommand
Displays spanning-tree information.
show spanning-tree
Configures the MST root swtich.
spanning-tree mst root
Catalyst 2960-X Switch Layer 2 Command Reference, Cisco IOS Release 15.0(2)EX
84 OL-29043 -01
Layer 2 Commands
spanning-tree extend system-id

Cisco Catalyst 2960-X Specifications

General

Console port	RJ-45
USB 2.0 ports quantity	2
SFP module slots quantity	4
Installed SFP modules quantity	-
Gigabit Ethernet (copper) ports quantity	48
Basic switching RJ-45 Ethernet ports type	Gigabit Ethernet (10/100/1000)
Power source	AC
Input current	5 A
AC input voltage	100 - 240 V
Power consumption (typical)	60.9 W
Number of power supply units	1
Redundant power supply (RPS) support	Yes
Operating altitude	0 - 3000 m
Non-operating altitude	0 - 4000 m
Storage temperature (T-T)	-25 - 70 °C
Operating temperature (T-T)	-5 - 40 °C
Operating relative humidity (H-H)	10 - 95 %
Switching protocols	UDP, TCP, RADIUS/TACACS+
Number of VLANs	1023
Networking standards	IEEE 802.1ab, IEEE 802.1D, IEEE 802.1p, IEEE 802.1Q, IEEE 802.1s, IEEE 802.1w, IEEE 802.1x, IEEE 802.3, IEEE 802.3ab, IEEE 802.3ad, IEEE 802.3ae, IEEE 802.3af, IEEE 802.3ah, IEEE 802.3at, IEEE 802.3az, IEEE 802.3u, IEEE 802.3x, IEEE 802.3z
Throughput	107.1 Mpps
Jumbo frames	9216
Number of queues	8
MAC address table	16000 entries
Number of static routes	1000
DHCP features	DHCP server
Authentication	MAC-based authentication, Port-based authentication
Security algorithms	802.1x RADIUS, SNMP, SSH
Access Control List (ACL) rules	3
Switch type	Managed
Switch layer	L2/L3
Safety	UL 60950-1, CAN/CSA-C22.2 No. 60950-1, EN 60950-1, IEC 60950-1, AS/NZS 60950-1
Form factor	1U
Product color	Black
Total Power over Ethernet (PoE) budget	370 W
Power over Ethernet (PoE) ports quantity	24
Power over Ethernet plus (PoE+) ports quantity	12
Memory type	DRAM
Noise level	39 dB
Flash memory	128 MB
Internal memory	512 MB
Processor frequency	600 MHz
Mean time between failures (MTBF)	276870 h

Weight and Dimensions

Depth	368 mm
Width	445 mm
Height	45 mm
Weight	5800 g