EC 304

[pc_evans]

Either of these answers will work depending on which switch the configurations are applied.

[*]Configure channel-group 1 mode desirable on both interfaces.
[*]Configure channel-group 1 mode active on both interfaces.

[*]configuring both interfaces of  switch3 for PAgP (desirable) would work
[*]configuring both interfaces of switch2 for LACP (active) would work

[pc_evans]

EC831 is a much better example for this question.