Routed Ports; Switch Virtual Interfaces - Cisco Catalyst 3750 Software Configuration Manual
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Also See for Catalyst 3750:
- Command reference manual (1154 pages) ,
- Hardware installation manual (231 pages) ,
- Message manual (120 pages)
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Understanding Interface Types
Routed Ports
A routed port is a physical port that acts like a port on a router; it does not have to be connected to a
router. A routed port is not associated with a particular VLAN, as is an access port. A routed port behaves
like a regular router interface, except that it does not support VLAN subinterfaces. Routed ports can be
configured with a Layer 3 routing protocol. A routed port is a Layer 3 interface only and does not support
Layer 2 protocols, such as DTP and STP.
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.
Caution
Entering a no switchport interface configuration command shuts down the interface and then re-enables
it, which might generate messages on the device to which the interface is connected.
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
page 9-18
For more information about IP unicast and multicast routing and routing protocols, see
"Configuring IP Unicast Routing,"
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 wish 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. SVIs provide IP host connectivity only to the system; in Layer 3 mode, you can
configure routing across SVIs.
Although the switch stack supports a total or 1005 VLANs (and SVIs), 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
page 9-18
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 802.1Q
encapsulated trunk or the VLAN ID configured for an access port. Configure a VLAN interface for each
VLAN for which you want to route traffic, and assign it an IP address. For more information, see the
"Manually Assigning IP Information" section on page
Note
When you create an SVI, it does not become active until it is associated with a physical port.
SVIs support routing protocols and bridging configurations. For more information about configuring IP
routing, see
Routing,"
Catalyst 3750 Metro Switch Software Configuration Guide
9-4
for information about what happens when hardware resource limitations are reached.
and
for information about what happens when hardware resource limitations are reached.
Chapter 28, "Configuring IP Unicast Routing," Chapter 31, "Configuring IP Multicast
and
Chapter 33, "Configuring Fallback Bridging."
Chapter 9
"Configuring Layer 3 Interfaces" section on
Chapter 31, "Configuring IP Multicast Routing."
"Configuring Layer 3 Interfaces" section on
3-9.
Configuring Interface Characteristics
Chapter 28,
78-15870-01
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Troubleshooting
