Cisco IE 4000, Руководство по настройке программного обеспечения

Страница: 46 / 1066

42
Configuring Interfaces
Configuring Layer 3 Interfaces
Configuring Layer 3 Interfaces
The switch must be running the IP services image to support Layer 3 interfaces:

SVIs: You should configure SVIs for any VLANs for which you want to route traffic. SVIs are created when you enter
a VLAN ID following the
interface vlan global configuration command. To delete an SVI, use the no interface vlan
global configuration command. You cannot delete interface VLAN 1.
When you create an SVI, it does not become active until it is associated with a physical port.

Routed ports: Routed ports are physical ports configured to be in Layer 3 mode by using the no switchport interface
configuration command.

Layer 3 EtherChannel ports: EtherChannel interfaces made up of routed ports.
A Layer 3 switch can have an IP address assigned to each routed port and SVI.
There is no defined limit to the number of SVIs and routed ports that can be configured in a switch. However, the
interrelationship between the number of SVIs and routed ports and the number of other features being configured might
have an impact on CPU usage because of hardware limitations. If the switch is using maximum hardware resources,
attempts to create a routed port or SVI have these results:

If you try to create a new routed port, the switch generates a message that there are not enough resources to convert
the interface to a routed port, and the interface remains as a switch port.

If you try to create an extended-range VLAN, an error message is generated, and the extended-range VLAN is
rejected.

If the switch attempts to boot up with a configuration that has more VLANs and routed ports than hardware can
support, the VLANs are created, but the routed ports are shut down, and the switch sends a message that this was
due to insufficient hardware resources.
All Layer 3 interfaces require an IP address to route traffic. This procedure shows how to configure an interface as a Layer
3 interface and how to assign an IP address to an interface.
Note: If the physical port is in Layer 2 mode (the default), you must enter the no switchport interface configuration
command to put the interface into Layer 3 mode. Entering a no switchport command disables and then re-enables the
interface, which might generate messages on the device to which the interface is connected. Furthermore, when you put
an interface that is in Layer 2 mode into Layer 3 mode, the previous configuration information related to the affected
interface might be lost, and the interface is returned to its default configuration
Beginning in privileged EXEC mode, follow these steps to configure a Layer 3 interface:
Command Purpose
1. configure terminal Enter global configuration mode.
2. interface {{ fastethernet | gigabitethernet } interface-id } |
{ vlan vlan-id } | { port-channel port-channel-number }
Specify the interface to be configured as a Layer 3
interface, and enter interface configuration mode.
3. no shutdown Enable the port, if necessary. By default, UNIs and ENIs
are disabled, and NNIs are enabled.
4. no switchport For physical ports only, enter Layer 3 mode.
5. ip address ip_address subnet_mask Configure the IP address and IP subnet.
6. no shutdown Enable the interface.