stacking with ethrecahnnel

[mynetwork014]

Hello,

regarding stacking and etherchannel 

follow the below network diagram.

Note: r3,r4 are cisco 3750x switches and r4 is hirschmann mach104-20tx-f switch

1. switch r3 and r6 connected to each other with stacking.
2. r3 f1/1 interface connected to r4 f1/1 and r6 f1/2 connected to r4f1/2 interface through etherchannel.

how can i achieve physical-redundancy(etherchannel) from r4 to r3,r6  

is it possible to create etherchannel(r4) with two different switch(r3,r6) sources.

is there any specific rules for etherchannel with stacking ?

[Leo Laohoo · Accepted solution]

is it possible to create etherchannel(r4) with two different switch(r3,r6) sources.

Yes it is possible and it's very common you can form an etherchannel to a stack of switches. 

is there any specific rules for etherchannel with stacking ?

Same rule applies:  Maximum of eight etherchannels and all physical link should be of the same speed. 

When configuring etherchannels on a switch stack always remember to think of the stack as a SINGLE LOGICAL SWITCH (and not as a multiple switches that form a stack).

[prajithtr_2 · Accepted solution]

Of course it is possible achieve.This method is called cross stack ether channel.Even though Cisco's proprietary  protocol PAgP doesn't support it,with LACP and without the ether-channel negotiation (ON)protocol also we can do it.Please check the IOS version because Only Software Release 12.2(25)SEC and later support  cross stack ether channel.please refer the below document.Pl

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/69979-cross-stack-etherchannel.html#config2

Regards

PrajithTR