Port Fast - Cisco Catalyst 2950 Software Manual

Features
Table 1-1 Features (continued)
Redundancy
HSRP for command switch redundancy
•
UniDirectional link detection (UDLD) on all Ethernet ports for detecting and disabling unidirectional links on
•
fiber-optic interfaces caused by incorrect fiber-optic wiring or port faults
IEEE 802.1d Spanning Tree Protocol (STP) for redundant backbone connections and loop-free networks. STP has these
•
features
Per-VLAN Spanning Tree (PVST) for balancing load across virtual LANs (VLANs)
–
Port Fast mode for eliminating forward delay by enabling a port to immediately change from a blocking state to a
–
forwarding state
UplinkFast, cross-stack UplinkFast, and BackboneFast for fast convergence after a spanning-tree topology change
–
and for achieving load balancing between redundant uplinks, including Gigabit uplinks and cross-stack Gigabit
uplinks
– STP root guard for preventing switches outside the network core from becoming the STP root
Note A Catalyst 2950 switch can support up to 64 spanning-tree instances (see
VLAN Support
Catalyst 2950 switches support 250 port-based VLANs for assigning users to VLANs associated with appropriate
•
network resources, traffic patterns, and bandwidth.
Note The Catalyst 2950-12 and Catalyst 2950-24 switches support only 64 port-based VLANs.
IEEE 802.1Q trunking protocol on all ports for network moves, adds, and changes; management and control of
•
broadcast and multicast traffic; and network security by establishing VLAN groups for high-security users and network
resources
• VLAN Membership Policy Server (VMPS) for dynamic VLAN membership
VLAN Trunking Protocol (VTP) pruning for reducing network traffic by restricting flooded traffic to links destined for
•
stations receiving the traffic
• Dynamic Trunking Protocol (DTP) for negotiating trunking on a link between two devices and for negotiating the type
of trunking encapsulation (802.1Q) to be used
Catalyst 2950 Desktop Switch Software Configuration Guide
1-4
Chapter 1
Table 8-1 on page 8-2).
Overview
78-11380-03