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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 1      Overview
    Features
• Port blocking on forwarding unknown unicast and multicast traffic (available only on the 
Catalyst LRE switches and on the Catalyst 2950G-12-EI, 2950G-24-EI, 2950G-24-EI-DC, 
2950G-48-EI, and 2955 switches)
• Per-port broadcast storm control for preventing faulty end stations from degrading overall system 
performance with broadcast storms
• Port Aggregation Protocol (PAgP) and Link Aggregation Control Protocol (LACP) for automatic 
creation of EtherChannel links
• Internet Group Management Protocol (IGMP) snooping for IGMP versions 1, 2, and 3 to limit 
flooding of IP multicast traffic
• IGMP report suppression for sending only one IGMP report per multicast router query to the 
multicast devices (supported only for IGMPv1 or IGMPv2 queries)
• IGMP snooping querier support to configure switch to generate periodic IGMP General Query 
messages
• Multicast VLAN registration (MVR) to continuously send multicast streams in a multicast VLAN 
while isolating the streams from subscriber VLANs for bandwidth and security reasons
• IGMP filtering for controlling the set of multicast groups to which hosts on a switch port can belong
• IGMP throttling for configuring the action when the maximum number of entries is in the IGMP 
forwarding table
• Protected port (private VLAN edge port) option for restricting the forwarding of traffic to designated 
ports on the same switch
• Dynamic address learning for enhanced security
Manageability
• Cisco Intelligence Engine 2100 (IE2100) Series Cisco Networking Services (CNS) embedded 
agents for automating switch management, configuration storage and delivery (available only with 
the EI)
• DHCP-based autoconfiguration for automatically configuring the switch during startup with IP 
address information and a configuration file that it receives during DHCP-based autoconfiguration
Note DHCP replaces the Bootstrap Protocol (BOOTP) feature autoconfiguration to ensure 
retrieval of configuration files by unicast TFTP messages. BOOTP is available in earlier 
software releases for this switch.
• DHCP server for automatic assignment of IP addresses and other DHCP options to IP hosts 
(available only on the Catalyst 2955 switch)
• Address Resolution Protocol (ARP) for identifying a switch through its IP address and its 
corresponding MAC address
• Unicast MAC address filtering to drop packets with specific source or destination MAC addresses 
(available only with the EI)
• Cisco Discovery Protocol (CDP) versions 1 and 2 for network topology discovery and mapping 
between the switch and other Cisco devices on the network
• Network Time Protocol (NTP) for providing a consistent time stamp to all switches from an external 
source