Chapter 15 Configuring Vlan, Vtp, And Vmp - Cisco Catalyst 4500 Series Configuration Manual

VLANs
VTP version 3 updates do not pass through promiscuous trunk ports.
Note
VLANs define broadcast domains in a Layer 2 network. A broadcast domain is the set of all devices that
receives broadcast frames originating from any device within the set. Broadcast domains are typically
bounded by switches because switches do not forward broadcast frames. Layer 2 switches create
broadcast domains based on the configuration of the switch. Switches are multiport bridges that allow
you to create multiple broadcast domains. Each broadcast domain is like a distinct virtual bridge within
a switch.
You can define one or many virtual bridges within a switch. Each virtual bridge you create in the switch
defines a new broadcast domain (VLAN). Traffic cannot pass directly to another VLAN (between
broadcast domains) within the switch or between two switches. To interconnect two different VLANs,
you must use switches or Layer 3 switches. See the
information on inter-VLAN routing on Catalyst 4500 series switches.
Figure 15-1
Figure 15-1
Cisco router
Ethernet
VLANs are often associated with IP subnetworks. For example, all of the end stations in a particular IP
subnet belong to the same VLAN. Traffic between VLANs must be routed. You must assign LAN
interface VLAN membership on an interface-by-interface basis (termed interface-based or static VLAN
membership).
You can set the following parameters when you create a VLAN in the management domain:
• VLAN number
• VLAN name
• VLAN type
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
15-2
shows an example of three VLANs that create logically defined networks.
Sample VLANs
Fast
"About Layer 3 Interfaces" section on page 32-1
Engineering Marketing
VLAN VLAN
Chapter 15 Configuring VLANs, VTP, and VMPS
Accounting
VLAN
for
Floor 3
Floor 2
Floor 1
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