Cisco Gigabit Ethernet Switch Module for HP p-Class BladeSystem Software Configuration Guide

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Cisco Gigabit Ethernet Switch Module for HP p-Class BladeSystem Software Configuration Guide
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Chapter 7 Configuring Interface Characteristics
Understanding Interface Types
VLAN partitions provide hard firewalls for traffic in the VLAN, and each VLAN has its own MAC
address table. A VLAN comes into existence when a local port is configured to be associated with the
VLAN, when the VLAN Trunking Protocol (VTP) learns of its existence from a neighbor on a trunk, or
when a user creates a VLAN.
To configure normal-range VLANs (VLAN IDs 1 to 1005), use the vlan vlan-id global configuration
command to enter config-vlan mode or the vlan database privileged EXEC command to enter VLAN
database configuration mode. The VLAN configurations for VLAN IDs 1 to 1005 are saved in the VLAN
database. To configure extended-range VLANs (VLAN IDs 1006 to 4094), you must use config-vlan
mode with VTP mode set to transparent. Extended-range VLANs are not added to the VLAN database.
When VTP mode is transparent, the VTP and VLAN configuration is saved in the switch running
configuration, and you can save it in the switch startup configuration file by entering the copy
running-config startup-config privileged EXEC command.
Add ports to a VLAN by using the switchport interface configuration commands:
• Identify the interface.
• For a trunk port, set trunk characteristics, and if desired, define the VLANs to which it can belong.
• For an access port, set and define the VLAN to which it belongs.
Switch Ports
Switch ports are Layer 2-only interfaces associated with a physical port. Switch ports belong to one or
more VLANs. A switch port can be an access port or a trunk port. You can configure a port as an access
port or trunk port or let the Dynamic Trunking Protocol (DTP) operate on a per-port basis to set the
switchport mode by negotiating with the port on the other end of the link. Switch ports are used for
managing the physical interface and associated Layer 2 protocols.
Configure switch ports by using the switchport interface configuration commands.
For detailed information about configuring access port and trunk port characteristics, see Chapter 9,
“Configuring VLANs.”
Access Ports
An access port belongs to and carries the traffic of only one VLAN (unless it is configured as a voice
VLAN port). Traffic is received and sent in native formats with no VLAN tagging. Traffic arriving on
an access port is assumed to belong to the VLAN assigned to the port. If an access port receives a tagged
packet (Inter-Switch Link [ISL] or IEEE 802.1Q tagged), the packet is dropped, and the source address
is not learned.
Two types of access ports are supported:
• Static access ports are manually assigned to a VLAN (or through a RADIUS server for use with
IEEE 802.1x. For more information, see the “Using IEEE 802.1x Authentication with VLAN
Assignment” section on page 6-10.)
• VLAN membership of dynamic access ports is learned through incoming packets. By default, a
dynamic access port is not a member of any VLAN, and forwarding to and from the port is enabled
only when the VLAN membership of the port is discovered. Dynamic access ports on the switch are
assigned to a VLAN by a VLAN Membership Policy Server (VMPS). The VMPS can be a
Catalyst 6500 series switch; theCatalyst switch cannot be a VMPS server.
You can also configure an access port with an attached Cisco IP Phone to use one VLAN for voice traffic
and another VLAN for data traffic from a device attached to the phone. For more information about
voice VLAN ports, see Chapter 11, “Configuring Voice VLAN.”