When a Switch-port is configured with Ether-Channel with PAgP or LACP the system will negotiate to make the port become active. When configuring the Ether-Channel on the ON mode for both sides, no negotiation will occur (Ports configured on the ON mode will not exchange PAgP packets). However the EtherChannel ON mode can be used to manually configure an Ether Channel without negotiations. The auto and desirable mode are used to start negotiations. For more information refer to: { http://www.cisco.com/c/en/us/td/docs/switches/metro/me3400/software/release/12-225ex/configuration/guide/3400scg/swethchl.html }- - - - - - - - - - - -From the same document just referenced: "A port in the auto mode cannot form an EtherChannel with another port that is also in the auto mode because neither port starts PAgP negotiation." -and- "A port in the passive mode cannot form an EtherChannel with another port that is also in the passive mode because neither port starts LACP negotiation." - - - - - HOWEVER, both PAgp/ desirable, and LACP/active "Places a port into an active negotiating state in which the port starts negotiations with other ports by sending PAgP or LACP packets."