Reference Guide

• Delete a Loopback interface.
CONFIGURATION mode
no interface loopback number
Many of the same commands found in the physical interface are also found in the Loopback interfaces.
For more information, refer to Configure ACLs to Loopback.
Null Interfaces
The Null interface is another virtual interface. There is only one Null interface. It is always up, but no traffic is
transmitted through this interface.
To enter INTERFACE mode of the Null interface, use the following command.
• Enter INTERFACE mode of the Null interface.
CONFIGURATION mode
interface null 0
The only configurable command in INTERFACE mode of the Null interface is the ip unreachable command.
Port Channel Interfaces
Port channel interfaces support link aggregation, as described in IEEE Standard 802.3ad.
This section covers the following topics:
• Port Channel Definition and Standards
• Port Channel Benefits
• Port Channel Implementation
• Configuration Tasks for Port Channel Interfaces
Port Channel Definition and Standards
Link aggregation is defined by IEEE 802.3ad as a method of grouping multiple physical interfaces into a single logical
interface—a link aggregation group (LAG) or port channel.
A LAG is “a group of links that appear to a MAC client as if they were a single link” according to IEEE 802.3ad. In FTOS, a
LAG is referred to as a port channel interface.
A port channel provides redundancy by aggregating physical interfaces into one logical interface. If one physical
interface goes down in the port channel, another physical interface carries the traffic.
Port Channel Benefits
A port channel interface provides many benefits, including easy management, link redundancy, and sharing.
Port channels are transparent to network configurations and can be modified and managed as one interface. For
example, you configure one IP address for the group and that IP address is used for all routed traffic on the port
channel.
With this feature, you can create larger-capacity interfaces by utilizing a group of lower-speed links. For example, you
can build a 5-Gigabit interface by aggregating five 1-Gigabit Ethernet interfaces together. If one of the five interfaces
fails, traffic is redistributed across the four remaining interfaces.
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