Channel Group Creation - Cisco MDS 9000 Series Configuration Manual

Configuring PortChannels
The PortChannel protocol uses two subprotocols:
• Bringup protocol—Automatically detects misconfigurations so you can correct them. This protocol
• Autocreation protocol—Automatically aggregates compatible ports into a PortChannel.

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 (see
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.
Figure 15: Autocreating Channel Groups
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 28: Channel Group Configuration Differences , on page 227
user-configured and auto-configured channel groups.
Table 28: Channel Group Configuration Differences
User-Configured Channel Group
Manually configured by the user.
Member ports cannot participate in autocreation
of channel groups. The autocreation feature
cannot be configured.
synchronizes the PortChannel at both ends so that all frames for a given flow (as identified by the source
FC ID, destination FC ID and OX_ID) are carried over the same physical link in both directions. This
helps make applications such as write acceleration, work for PortChannels over FCIP links.
Figure 15: Autocreating Channel Groups, on page
Autocreated Channel Group
Created automatically when compatible links come up
between two compatible switches, if channel group
autocreation is enabled in all ports at both ends.
None of these ports are members of a user-configured
channel group.
Cisco MDS 9000 Series Interfaces Configuration Guide, Release 8.x
Channel Group Creation
227), that link is
identifies the differences between
227