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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 1 Overview
Features
VLAN Features
• Support for up to 1005 VLANs for assigning users to VLANs associated with appropriate network
resources, traffic patterns, and bandwidth
• Support for VLAN IDs in the full 1 to 4094 range allowed by the IEEE 802.1Q standard
• VLAN Query Protocol (VQP) for dynamic VLAN membership
• IEEE 802.1Q trunking encapsulation 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 1 minimization for reducing 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 on the trunk. The switch CPU continues to send and receive control protocol frames.
• UNI-ENI isolated VLANs to isolate customer VLANs from VLANs of other customers on the same
switch. Local switching does not occur among UNIs or ENIs on the switch that belong to the same
UNI-ENI isolated VLAN.
• Private VLANs to address VLAN scalability problems, to provide a more controlled IP address
allocation, a nd to allow Layer 2 ports to be isolated from ports on other switches
• Port security on a PVLAN host to limit the number of MAC addresses learned on a port, or define
which MAC addresses may be learned on a port
• VLAN Flex Link Load Balancing to provide Layer 2 redundancy without requiring Spanning Tree
Protocol (STP). A pair of interfaces configured as primary and backup links can load balance traffic
based on VLAN.
Security Features
The switch provides security for the subscriber, the switch, and the network.

Subscriber Security

• By default, local switching is disabled among subscriber ports to ensure that subscribers are
isolated.
• DHCP snooping to filter untrusted DHCP messages between untrusted hosts and DHCP servers
• DHCP Snooping Statistics show and clear commands to display and remove DHCP snooping
statistics in summary or detail form
• IP source guard to restrict traffic on nonrouted interfaces by filtering traffic based on the DHCP
snooping database and IP source bindings
• Dynamic ARP inspection to prevent malicious attacks on the switch by not relaying invalid ARP
requests and responses to other ports in the same VLAN
Note IP source guard and dynamic ARP inspection are available only when the switch is running the metro IP
access or metro access image.