> # Channel Group Creation

> Note Channel groups are not supported on internal ports in the Cisco Fabric Switch for HP c-Class BladeSystem and the Cisco Fabric Switch for IBM BladeSystem.

> Assuming link A1-B1 comes up first, that link is operational as an individual link.When the next link comes up, for example, A2-B2, the PortChannel protocol identifies if this link is compatible with link A1-B1 and automatically creates channel groups 10 and 20 in the respective switches. If link A3-B3 can join the channel groups (the PortChannels), the respective ports have compatible configurations. If link A4-B4 operates as an individual link, it is because of the incompatible configuration of the two end ports with the other member ports in this channel group.

> The channel group numbers are selected dynamically, and as such, the administrative configuration of the ports forming the channel group at either end are applicable to the newly created channel group. The channel group number being chosen dynamically may be different across reboots for the same set of PortChannels based on the order of ports that are initialized in the switch.

> Table 10-2 identifies the differences between user-configured and auto-configured channel groups.

> Table 10-2 Channel Group Configuration Differences
> User-Configured Channel Group | Autocreated Channel Group
> --- | ---
> Manually configured by the user. | Created automatically when compatible links come up between two compatible switches, if channel group autocreation is enabled in all ports at both ends.
> Member ports cannot participate in autocreation of channel groups. The autocreation feature cannot be configured. | None of these ports are members of a user-configured channel group.
> You can form the PortChannel with a subset of the ports in the channel group. Incompatible ports remain in a suspended or isolated state depending on the ON or ACTIVE mode configuration. | All ports included in the channel group participate in the PortChannel—no member port becomes isolated or suspended; instead, the member port is removed from the channel group when the link is found to be incompatible.
> Any administrative configuration made to the PortChannel is applied to all ports in the channel group, and you can save the configuration for the PortChannel interface. | Any administrative configuration made to the PortChannel is applied to all ports in the channel group, but the configurations are saved for the member ports; no configuration is saved for the PortChannel interface. You can explicitly convert this channel group, if required.
> You can remove any channel group and add members to a channel group. | You cannot remove a channel group, or add/remove any of its members. The channel group is removed when no member ports exist.

> Note Autocreation is not supported as of MDS NX-OS Release 4.1(1b) and later.

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