Vlan Support - Cisco Catalyst 2950 Software Configuration Manual

Features
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VLAN Support

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Security
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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
1-6
Optional spanning-tree features available in the PVST+, rapid PVST+, and MSTP modes:
Port Fast for eliminating the forwarding delay by enabling a port to immediately transition from
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the blocking state to the forwarding state
– BPDU guard for shutting down Port Fast-enabled ports that receive BPDUs
BPDU filtering for preventing a Port Fast-enabled port from sending or receiving BPDUs
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– Root guard for preventing switches outside the network core from becoming the spanning-tree
root
– Loop guard for preventing alternate or root ports from becoming designated ports because of a
failure that leads to a unidirectional link
The switches support 250 port-based VLANs for assigning users to VLANs associated with
appropriate network resources, traffic patterns, and bandwidth
The Catalyst 2950-12, Catalyst 2950-24, Catalyst 2950SX-24, Catalyst 2950SX-48-SI, and
Note
Catalyst 2950T-48-SI switches support only 64 port-based VLANs.
The switch supports up to 4094 VLAN IDs to allow service provider networks to support the number of
VLANs allowed by the IEEE 802.1Q standard (available only with the EI)
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 (IEEE 802.1Q) to be used
Voice VLAN for creating subnets for voice traffic from Cisco IP Phones
VLAN 1 minimization to reduce the risk of spanning-tree loops or storms by allowing VLAN 1 to
be disabled on any individual VLAN trunk link. With this feature enabled, no user traffic is sent or
received. The switch CPU continues to send and receive control protocol frames.
Bridge protocol data unit (BPDU) guard for shutting down a Port Fast-configured port when an
invalid configuration occurs
Protected port option for restricting the forwarding of traffic to designated ports on the same switch
Password-protected access (read-only and read-write access) to management interfaces (device
manager, Network Assistant, and CLI) for protection against unauthorized configuration changes
Port security option for limiting and identifying MAC addresses of the stations allowed to access
the port
Port security aging to set the aging time for secure addresses on a port
Chapter 1 Overview
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