Cisco Catalyst 2960-X Command Reference

spanning-tree uplinkfast
To enable UplinkFast, use the spanning-tree uplinkfast command in global configuration mode. To disable
UplinkFast, use the no form of this command.
spanning-tree uplinkfast [max-update-rate packets-per-second]
no spanning-tree uplinkfast [max-update-rate]
Syntax Description
(Optional) Specifies the rate (number of packets per second) at which
update packets are sent. The range is 0 to 320000.
The default is 150.
max-update-rate
packets-per-second
Command Default
UplinkFast is disabled.
Command Modes
Global configuration
Command History
ModificationRelease
This command was introduced.Cisco IOS 15.0(2)EX
Usage Guidelines
Use this command only on access switches.
You can configure the UplinkFast feature for rapid PVST+ or for multiple spanning-tree (MST) mode, but
the feature remains disabled (inactive) until you change the spanning-tree mode to PVST+.
When you enable UplinkFast, it is enabled for the entire switch; it cannot be enabled for individual VLANs.
When you enable or disable UplinkFast, cross-stack UplinkFast (CSUF) also is automatically enabled or
disabled on all nonstack port interfaces. CSUF accelerates the choice of a new root port when a link or switch
fails or when spanning tree reconfigures itself.
When UplinkFast is enabled, the switch priority of all VLANs is set to 49152. If you change the path cost to
a value less than 3000 and you enable UplinkFast or UplinkFast is already enabled, the path cost of all interfaces
and VLAN trunks is increased by 3000 (if you change the path cost to 3000 or above, the path cost is not
altered). The changes to the switch priority and the path cost reduces the chance that a switch will become
the root switch.
When UplinkFast is disabled, the switch priorities of all VLANs and path costs of all interfaces are set to
default values if you did not modify them from their defaults.
When spanning tree detects that the root port has failed, UplinkFast immediately changes to an alternate root
port, changing the new root port directly to forwarding state. During this time, a topology change notification
is sent.
Catalyst 2960-X Switch Layer 2 Command Reference, Cisco IOS Release 15.0(2)EX
OL-29043 -01 111
Layer 2 Commands
spanning-tree uplinkfast

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