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Why access mode port channel causing loops

susim
Level 3
Level 3

What all  are the possiblities a port channel ( all the ports are in access mode )  creates loop in the networks ?

Thank you

3 Replies 3

Reza Sharifi
Hall of Fame
Hall of Fame

When one end of an EtherChannel has more members than the other, the unmatched ports enter the standalone state. In a topology that is not protected from Layer 2 loops by the spanning tree protocol (STP), a port in the standalone state can cause significant network errors. For LACP EtherChannels with Release 12.2(33)SXI3 and later releases, you can enter the

port-channel standalone-disable

interface configuration mode command to put ports into the suspended state instead of the standalone state. See the

"Configuring LACP Port-Channel Standalone Disable" section. When one end of an EtherChannel

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/channel.html

HTH

When one end of an EtherChannel has more members than the other....

No both end  has same number of members

Peter Paluch
Cisco Employee
Cisco Employee

Hi,

Reza is absolutely correct. You may be interested to read the following thread:

https://supportforums.cisco.com/message/3241191#3241191

In quite a large scale, we have discussed how an improper configuration of EtherChannels leads to switching loops. Note that it is not important if the EtherChannel operates as an access or a trunk port.

Best regards,

Peter

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