Cisco Catalyst 3560-X Series, Software Configuration Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 Configuring Interface Characteristics
Interface Types
Note Routed ports are not supported on switches running the LAN Base feature set. However, starting with
Cisco ICO release 12.2(58)SE, you can configure up to 16 static routes on SVIs.
Configure routed ports by putting the interface into Layer 3 mode with the no switchport interface
configuration command. Then assign an IP address to the port, enable routing, and assign routing
protocol characteristics by using the
ip routing and router protocol global configuration commands.
Note
Entering a no switchport interface configuration command shuts down the interface and then reenables
it, which might generate messages on the device to which the interface is connected. 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.
The number of routed ports that you can configure is not limited by software. However, the
interrelationship between this number and the number of other features being configured might impact
CPU performance because of hardware limitations. See the
“Configuring Layer 3 Interfaces” section on
page 1-40 for information about what happens when hardware resource limitations are reached.
For more information about IP unicast and multicast routing and routing protocols, see Chapter 1,
“Configuring IP Unicast Routing” and Chapter 1, “Configuring IP Multicast Routing.”
Note
The IP Base feature set supports static routing and the Routing Information Protocol (RIP). Starting with
Cisco IOS Release 12.2(58)E, the LAN Base feature set supports 16 user-configured static routes on
SVIs. For full Layer 3 routing or for fallback bridging, you must enable the IP Services feature set on
the standalone switch, or the active switch.
Switch Virtual Interfaces
A switch virtual interface (SVI) represents a VLAN of switch ports as one interface to the routing or
bridging function in the system. Only one SVI can be associated with a VLAN, but you need to configure
an SVI for a VLAN only when you want to route between VLANs, to fallback-bridge nonroutable
protocols between VLANs, or to provide IP host connectivity to the switch. By default, an SVI is created
for the default VLAN (VLAN 1) to permit remote switch administration. Additional SVIs must be
explicitly configured.
Note
You cannot delete interface VLAN 1.
SVIs provide IP host connectivity only to the system; in Layer 3 mode, you can configure routing across
SVIs.
Although the switch stack or switch supports a total of 1005 VLANs and SVIs (255 if the switch is
running the LAN Base feature set), the interrelationship between the number of SVIs and routed ports
and the number of other features being configured might impact CPU performance because of hardware
limitations. See the
“Configuring Layer 3 Interfaces” section on page 1-40 for information about what
happens when hardware resource limitations are reached.
SVIs are created the first time that you enter the vlan interface configuration command for a VLAN
interface. The VLAN corresponds to the VLAN tag associated with data frames on an ISL or
IEEE 802.1Q encapsulated trunk or the VLAN ID configured for an access port. Configure a VLAN