Initial Switch Configuration
Assign Initial Management Information
22
Best Practice User Guide for the Catalyst 3850 and Catalyst 3650 Switch Series
Configure a Management IP Address on an Out-of-Band Interface
Step 8
Assign an IP address to an out-of-band interface.
Out-of-band management is managing the switch and all other networking devices through a physical
network, which is separate from the production network that carries end-user traffic. To manage the
switch with an out-of-band network, the switch uses the GigabitEthernet 0/0 interface. The
GigabitEthernet0/0 interface is physically located on the rear of the switch, next to the blue console port.
The following are the advantages of a GigabitEthernet 0/0 interface:
•
The interface is not susceptible to network outages, such as broadcast storms or other potential
issues on the production network because it is separated from the data plane.
•
The interface is out-of-band and allows the switch and all other networking devices to always be
manageable so that you can quickly respond whenever there is a network issue.
Step 9
Configure a Virtual Routing and Forwarding (VRF) instance.
The out-of-band management interface is in its own VRF instance. This means that the routing database
and protocol exchange are also separate for this interface from the other data network interfaces.
The following are the limitations of a GigabitEthernet 0/0 interface.
•
Management traffic originating from the switch must be associated with the GigabitEthernet 0/0
VRF instance. A Mgmt-vrf is used to segment management traffic from the global routing table of
the switch.
•
A default route for the Mgmt-vrf is required.
•
This interface cannot be used as the source interface for sending SNMP traps. Sending traps to an
SNMP trap server requires an IP address on a VLAN interface, see the
IP Address on an In-Band Interface”
section.
Note
Use the IP address value that you listed in the print-out (
) for the out-of-band management
configuration.
In the following example, the GigabitEthernet 0/0 interface is not on the switch data plane. This interface
(also referred to as the service port) is terminated on the CPU of the switch as opposed to a logical
interface of the forwarding ASIC. The GigabitEthernet 0/0 differs from the Ethernet interfaces on the
front of the switch because it is only a Layer 3 interface (also referred to as a routable interface). The
Ethernet interfaces on the front of the switch default to Layer 2 mode and are used for bridging.
The Ethernet interfaces on the front can be configured to be a routable interface using the
no switchport
interface command. The GigabitEthernet 0/0 interface will not function without an IP address assigned
to it.
Mgmt-vrf is built-in; you do not have to create one for out-of-band management.
