Cisco Catalyst 3750 User Manual

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Catalyst 3750 Switch Command Reference
OL-8552-07
Chapter 2 Catalyst 3750 Switch Cisco IOS Commands
spanning-tree portfast (interface configuration)
spanning-tree portfast (interface configuration)
Use the spanning-tree portfast interface configuration command to enable the Port Fast feature on an
interface in all its associated VLANs. When the Port Fast feature is enabled, the interface changes
directly from a blocking state to a forwarding state without making the intermediate spanning-tree state
changes. Use the no form of this command to return to the default setting.
spanning-tree portfast [disable | trunk]
no spanning-tree portfast
Syntax Description
Defaults The Port Fast feature is disabled on all interfaces; however, it is automatically enabled on
dynamic-access ports.
Command Modes Interface configuration
Command History
Usage Guidelines Use this feature only on interfaces that connect to end stations; otherwise, an accidental topology loop
could cause a data packet loop and disrupt switch and network operation.
To enable Port Fast on trunk ports, you must use the spanning-tree portfast trunk interface
configuration command. The spanning-tree portfast command is not supported on trunk ports.
You can enable this feature when the switch is operating in the per-VLAN spanning-tree plus (PVST+),
rapid-PVST+, or the multiple spanning-tree (MST) mode.
This feature affects all VLANs on the interface.
An interface with the Port Fast feature enabled is moved directly to the spanning-tree forwarding state
without the standard forward-time delay.
You can use the spanning-tree portfast default global configuration command to globally enable the
Port Fast feature on all nontrunking interfaces. However, the spanning-tree portfast interface
configuration command can override the global setting.
If you configure the spanning-tree portfast default global configuration command, you can disable
Port Fast on an interface that is not a trunk interface by using the spanning-tree portfast disable
interface configuration command.
disable (Optional) Disable the Port Fast feature on the specified interface.
trunk (Optional) Enable the Port Fast feature on a trunking interface.
Release Modification
12.1(11)AX This command was introduced.

Cisco Catalyst 3750 Specifications

General

Device Type	Switch
Switching Capacity	32 Gbps
Forwarding Rate	38.7 Mpps
Stacking Bandwidth	32 Gbps
RAM	128 MB
Jumbo Frame Support	Yes
Switch Type	Managed
Model	Catalyst 3750 Series
Uplink Interfaces	SFP
Form Factor	Rack-mountable
MAC Address Table Size	12, 000 entries
Routing Protocol	RIP, OSPF, EIGRP
Remote Management Protocol	SNMP, Telnet, HTTP
Features	Layer 3 switching, Layer 2 switching, auto-negotiation, BOOTP support, ARP support, VLAN support, auto-uplink (auto MDI/MDI-X), IGMP snooping, traffic shaping, MAC address filtering, Quality of Service (QoS), Jumbo Frames support, MLD snooping, Dynamic ARP Inspection (DAI), Cisco EnergyWise technology
Power over Ethernet (PoE)	PoE
Operating Temperature	-5 - 45 °C
Operating Humidity	10% to 85% non-condensing