Udld; Unidirectional Ethernet; Vlans - Cisco 4500M Software Manual

Chapter 1 Product Overview

UDLD

The UniDirectional Link Detection (UDLD) protocol allows devices connected through fiber-optic or
copper Ethernet cables to monitor the physical configuration of the cables and detect a unidirectional
link.
For information about UDLD, see

Unidirectional Ethernet

Unidirectional Ethernet uses only one strand of fiber for either transmitting or receiving one-way traffic
for the Gigaport, instead of two strands of fiber for a full-duplex Gigaport Ethernet.
For information about Unidirectional Ethernet, see

VLANs

A VLAN configures switches and routers according to logical, rather than physical, topologies. Using
VLANs, a network administrator can combine any collection of LAN segments within an internetwork
into an autonomous user group, such that the segments appear as a single LAN in the network. VLANs
logically segment the network into different broadcast domains so that packets are switched only
between ports within the VLAN. Typically, a VLAN corresponds to a particular subnet, although not
necessarily.
For more information about VLANs, see
The following VLAN-related features are also supported.
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VLAN Trunking Protocol (VTP)—VTP maintains VLAN naming consistency and connectivity
between all devices in the VTP management domain. You can have redundancy in a domain by using
multiple VTP servers, through which you can maintain and modify the global VLAN information.
Only a few VTP servers are required in a large network.
For more information about VTP, see
Private VLANs—Private VLANs are sets of ports that have the features of normal VLANs and also
provide some Layer 2 isolation from other ports on the switch.
For information about private VLANs, see
Private VLAN Trunk Ports—Private VLAN trunk ports allow a secondary port on a private VLAN
to carry multiple secondary VLANs.
Dynamic VLAN Membership—Dynamic VLAN Membership allows you to assign switch ports to
VLANs dynamically, based on the source Media Access Control (MAC) address of the device
connected to the port. When you move a host from a port on one switch in the network to a port on
another switch in the network, that switch dynamically assigns the new port to the proper VLAN for
that host. With the VMPS Client feature, you can convert a dynamic access port to a VMPS client.
VMPS clients can use VQP queries to communicate with the VMPS server to obtain a VLAN
assignment for the port based on the MAC address of the host attached to that port. For more
information about Dynamic VLAN Membership, see
Membership."
Chapter 21, "Configuring UDLD."
Chapter 22, "Configuring Unidirectional Ethernet."
Chapter 10, "Understanding and Configuring VLANs."
Chapter 27, "Understanding and Configuring VTP."
Chapter 36, "Configuring Private VLANs."
Chapter 11, "Configuring Dynamic VLAN
Software Configuration Guide—Release 12.2(25)EW
Layer 2 Software Features
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