# EtherChannel

Device>Configure>EtherChannel

The EtherChannel dialog box displays information about the Fast Ethernet Channels (100 Mbps) you configure for your devices. You define EtherChannels between two devices’ Ethernet ports. Please note that if you are running older Catalyst software, only a subset of the following features are available.

Note: If an Ethernet port is set to a Desirable status, it can initiate a negotiation with another devices’ Ethernet port to become an EtherChannel. If an Ethernet port is set to Auto, it will not initiate a negotiation to become an EtherChannel, but it can accept the request from the other device’s desirable port based on the PAgP (Port Aggregation Protocol; a Cisco proprietary protocol). Desirable and Auto port states are software driven protocol negotiation processes for EtherChannels. You can alternatively create EtherChannels manually (which are automatically given an On status); such EtherChannels are used by the Catalyst software directly without an intermediary protocol negotiation process. Auto and Desirable settings are not available for older Catalyst releases; if you are running an older release, use the Create EtherChannel option to manually define EtherChannel groups.

EtherChannel Options: Use the following button functions to establish EtherChannel settings and port groupings for the device:
Click Create EtherChannel... to display the Configure EtherChannels dialog box, in which you

1. Manually create EtherChannels by specifying which ports on each card are to be grouped into one EtherChannel.

2. Delete EtherChannel groupings for this device.

3. Convert Auto or Desirable EtherChannels ports to On or Off.

Note: When you create an EtherChannel, the default port state is set On. If you delete an EtherChannel, the port state is set to Off. An On port-state setting cannot be changed to Desirable or Auto (the corresponding button options will be disabled) until you first enter the Create EtherChannel window and change the port state to Off. See the EtherChannel MIBs section below for more information about creating new EtherChannels and establishing their status settings.

Click Desirable to set two Ethernet ports on the same device to the desirable state. A desirable port initiates a PAgP negotiation request to become a channel and will become a channel if the far end agrees. Two separate sets of actions must be performed in order to set four ports to desirable. For example, to set 5/9-12 to desirable, select port 9 or 10 on card 5 first, click the Desirable button, then select port 11 or 12 on card 5 and again click the Desirable button.

Click Auto to set two ports on the same device to the auto state. An auto port does not initiate a PAgP request to become an EtherChannel but will accept the request from the far end. As with the Desirable button feature, two separate actions must be performed in order to set four ports to auto. For example, to set 3/9-12 to auto, select port 9 or 10 on card 3 first, click the Auto button, then select port 11 or 12 on card 3, and again click the Auto button.

Click Show EtherChannels to highlight specific EtherChannels on the device’s rear view. Channeled ports are enclosed in the blue rectangles; white rectangles represent ports that are not yet channeled.

Click Refresh to retrieve the latest data from the SNMP agent.

EtherChannel MIBs Table

Port(s) (portChannelPorts)

Identifies both the slot and Ethernet port number you set for use as an EtherChannel. For example, a port entry reading 5/2 indicates that port 2 on the card 5 module is defined as a channel. The number of entries is determined by the number of Ethernet ports in your system that support Ethernet Channeling functionality.

Administrative Status (portChannelAdminStatus)

Indicates the current state of the channeled ports; Auto, Desirable, On, Off, desirableSilent, or autoSilent.

Note: The EtherChannel ports on two devices can be configured to have either (1) an Auto port status on one device’s port, with a Desirable port status on the other device end, or (2) a port status of On set manually for both devices’ ports. Auto and Desirable states are driven by the Catalyst software; i.e., the software determines whether or not it will use these EtherChannels, depending on protocol negotiations. The On and Off states, alternatively, are set manually by you. An On state does not undergo any protocol negotiation; it is an EtherChannel used directly by the Catalyst software without an intermediary protocol negotiation process.

Auto. An EtherChannel port state set via the Auto button. Although an auto state does not originate a request to become an EtherChannel, it will accept such a request from the other device’s port when that other port is set to Desirable.

Desirable. An EtherChannel port state set via the Desirable button. A desirable port initiates a PAgP negotiation request to become a channel and will become a channel if the far end agrees.

On. An Ethernet port state set via the Create EtherChannel button. When status is set manually to On, port channeling is enabled. When setting Etherchannels manually with this feature, remember that both devices’ Ethernet ports must be set to On to allow the software to recognize them and use them. On channels are grouped and ready, but only become active when the software uses them; actively channeling ports are displayed in the Channeled Ports column of the EtherChannel table. Click the Refresh button to retrieve the latest data from the SNMP agent. See also Configure EtherChannels for more information about setting the On state by grouping ports into EtherChannels.

Off. An Ethernet port state set via the Create EtherChannel button. When status is set manually to Off, port channeling is disabled. See Configure EtherChannels for more information about setting an Off state when grouping ports into EtherChannels.

desirableSilent. An Ethernet port state set via the Create EtherChannel button. When status is set manually to desirableSilent, the port initiates a PAgP negotiation request to become a channel and will become a channel if the far end agrees. If the port does not receive any packets from the far end, then the port forms a channel by itself after a timeout period.

autoSilent. An Ethernet port state set via the Create EtherChannel button. When status is set manually to autoSilent, the port does not initiate a request to become a channel. However, if it receives a request to become a channel from the far end, the channel is formed. If the port does not receive any requests, then the port forms a channel by itself after a timeout period.

Operational Status (portChannelOperStatus)

Current operating status of the channeled ports. For example, a channel might be set to On, but it is not actively channeling unless its group is displayed in the Channeled Ports column of the EtherChannel table.

Neighbor Device (portChannelNeighbourDeviceId)

MAC address ID for the selected port on the neighbor device.

Neighbor Port (portChannelNeighbourPortId)

Indicates the neighbor port ID.

Click Cancel to close the dialog box. Click Print to print the contents of the dialog box.