EtherChannel on Stacked Cisco Switches

[antony63593]

Hello everyone,

I am a student and i have a diagram (theoric) to do. I want to stack 5 access together, and i was wondering if i could link those stacked switches via EtherChannel to the distribution switch using one port on every of the 5 stacked switches ?

Sadly i can't try this out with CPT (that i know of).

Is it possible ?

Second question, how are the stacked switches interfaces presented ? Are they merged ? What's the naming convention ?

I am sorry if that's a lot of questions but i had no idea where to easilly find those answers.

Thanks a ton !

[Joseph W. Doherty]

Yes and presented as a port-channel interface.

[Martin L]

Yes, simply create an ether-channel using interfaces you want - usually from fiber module 1.  interface range gig1/1/1 -1/1/4, gig2/1/1-2/1/4, etc. Or using cat5 ports Fa1/0/48, Fa2/0/48, Fa3/0/48, ... Fa5/0/48

With x switches in stack first number will be switch id (x), 2nd number is module number (0 or 1) and last number is port number (y).  With 5 switches, your 3rd switch port 12 should appear as 3/0/12. while 5th one as 5/0/12.

Build in (fixed) ports on switch are 0 in x/0/y while uplink or add-on fiber ports are 1 so x/1/y.  If you buy 1 used c3750, it already comes with format of ports as x/0/y, you cannot have x/y on any stackable switches. If you split stack, format x/0/y stays.

All ports and all switches in a stack are as one "big" switch.  you simply adding more ports. while you can mix 24 port switch with 48 port one in the same stack, it is not recommended. Top switch (on top of stack) should be switch #1; adding new switch to existing stack will take next available switch number (x). 

Regards, ML
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[Joseph W. Doherty]

". . . while you can mix 24 port switch with 48 port one in the same stack, it is not recommended."

Interesting!  Do you have a reference to this recommendation?

[Martin L]

i would not recommend it because it may create confusions if there are several switches in different locations.

Regards, ML
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[paul driver]

Hello
Mixed stacks are viable depending on what model of the switch, Im aware 3750's supported it as long as they had a compatiable ios version & feature set you could stack a 24 and 48 port switch together, As for the new 9000 catalyst again i beleive mix stacking is viable between same model of switch.

[Joseph W. Doherty]

Ah, well, yes perhaps your recommendation, of not mixing different number of member switch ports, avoids some confusion.  It also might apply better to "small" networks and/or less experienced network engineers.

My experience, with both 3750 stacks (also non-Cisco stacks), and chassis switches, both might have many different port quantities and/or kind/types, for the "whole" device.  (E.g. FE vs. gigE, non-PoE vs. PoE, and/or copper vs. fiber.)