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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
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Chapter 11 Configuring Interface Characteristics
Understanding Interface Types
Tunnel Ports
Tunnel ports are used in IEEE 802.1Q tunneling to segregate the traffic of customers in a
service-provider network from other customers who are using the same VLAN number. You configure
an asymmetric link from a tunnel port on a service-provider edge switch to an IEEE 802.1Q trunk port
on the customer switch. Packets entering the tunnel port on the edge switch, already
IEEE 802.1Q-tagged with the customer VLANs, are encapsulated with another layer of an IEEE 802.1Q
tag (called the metro tag), containing a VLAN ID unique in the service-provider network, for each
customer. The double-tagged packets go through the service-provider network keeping the original
customer VLANs separate from those of other customers. At the outbound interface, also a tunnel port,
the metro tag is removed, and the original VLAN numbers from the customer network are retrieved.
Tunnel ports cannot be trunk ports or access ports and must belong to a VLAN unique to each customer.
For more information about tunnel ports, see
Chapter 17, “Configuring IEEE 802.1Q and Layer 2
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.
Note
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. 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
for information about what happens when hardware resource limitations are reached.
For more information about IP unicast and multicast routing and routing protocols, see
“Configuring IP Unicast Routing”
Chapter 44, “Configuring IP Multicast Routing.”
Note
The IP base feature set supports static routing and the Routing Information Protocol (RIP). For full
Layer 3 routing or for fallback bridging, you must enable the IP services feature set on the standalone
switch, or the stack master.
