channel-group [id] mode [mode]
Assigns an interface to an EtherChannel bundle with a specified channel-group number and mode (active, passive, or desirable) to aggregate multiple physical links into a single logical link for redundancy and increased bandwidth.
channel-group [id] mode [mode]When to Use This Command
- Aggregating two or more trunk links between switches to increase uplink bandwidth and provide redundancy.
- Combining access ports connecting a server to a switch for higher throughput and fault tolerance.
- Configuring LACP (active/passive) to negotiate EtherChannel with a partner switch that supports LACP.
- Using PAgP (desirable/auto) to form EtherChannel with a Cisco switch that only supports PAgP.
Command Examples
Configure LACP Active on an Interface
interface GigabitEthernet0/1
channel-group 1 mode activeGigabitEthernet0/1 is now in port-channel 1
The interface is added to channel-group 1 with LACP active mode, meaning it will actively negotiate the EtherChannel with the neighbor.
Configure PAgP Desirable on an Interface
interface FastEthernet0/2
channel-group 2 mode desirableFastEthernet0/2 is now in port-channel 2
The interface is added to channel-group 2 with PAgP desirable mode, initiating negotiation with the neighbor.
Understanding the Output
The command produces minimal output, typically just confirming the interface is added to the port-channel. To verify the EtherChannel status, use 'show etherchannel summary' or 'show etherchannel port-channel'. In 'show etherchannel summary', look for the port-channel interface (e.g., Port-channel1) and its status (SU for layer2 up, SD for down). The member ports are listed with flags: 'P' for bundled in port-channel, 'S' for suspended, 'D' for down. A good EtherChannel shows all member ports as 'P' and the port-channel status as 'SU'. If any port shows 'S' or 'D', check for mismatched configurations (e.g., speed, duplex, VLAN allowed).
CCNA Exam Tips
CCNA exam tip 1: LACP modes are 'active' and 'passive'; PAgP modes are 'desirable' and 'auto'. At least one side must be active/desirable to form the channel.
CCNA exam tip 2: All interfaces in a channel group must have the same speed, duplex, and VLAN configuration (or trunk allowed VLANs).
CCNA exam tip 3: The maximum number of interfaces in an EtherChannel is 8 (up to 16 with LACP standby).
CCNA exam tip 4: On the CCNA exam, remember that 'channel-group' is configured under interface configuration mode, not global config.
Common Mistakes
Mistake 1: Mixing LACP and PAgP modes on the same channel group — they are incompatible and the channel will not form.
Mistake 2: Forgetting to configure the same allowed VLANs on all member trunk ports, causing some ports to be suspended.
Mistake 3: Using 'channel-group' without first creating the port-channel interface (though IOS auto-creates it, but best practice is to create it manually).
Related Commands
Practice for the CCNA 200-301
Test your knowledge with hundreds of CCNA practice questions covering all exam domains.
Practice CCNA Questions