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M-LAG between 4 agregation switches

Userlevel 4
Create Date: Oct 5 2013 4:26PM


I have a campus network composed of many access switches (X460) in buildings, on two sides of a street.

I would like to set up an agregation layer composed of four X670 switches (two on each side of the street), so that i can have redundant connections between each access switch and its two agregation switches). I also need to propagate vlans between these agregation switches.

I plan to use M-LAG :

    between each access switch and its two agregation switches (no problem, standard design) between the four agregation switches, in full-mesh flavour => here i have a doubt.
I have searched for design guidelines in the XOS concepts guide, in this forum and other websites but never found a clear answer to the question : how many M-LAGs do i have to create on the agregation switches for the full-mesh connection of these four switches ?

As stated in the drawing below, i gues that i would have to create four regular LAGs and also four M-LAGs (for each regular LAG on a X670, i have to declare the corresponding M-LAG on the two X670 on the other side) :


So I gues i would declare this configuration (just talking about X670 full-mesh connection, here i don't consider the LAG for the ISC link and the M-LAGs for the access switches):

X670 #1 : LAG 1 and M-LAG 3 and 4
X670 #2 : LAG 2 and M-LAG 3 and 4
X670 #3 : LAG 3 and M-LAG 1 and 2
X670 #4 : LAG 4 and M-LAG 1 and 2

Am i correct ?
If someone already tested this design or have suggestions about it, i'm very interested.

Best regards,

(from Gabrielboubil)

4 replies

Userlevel 4
Create Date: Oct 7 2013 1:48PM

IMO, you only need one MLAG in each switch, which will contain one lag from each. It's not even possible to create a M-LAG with the second port of a LAG, because there is no way to refer to this second port. When you create a lag only the master port is used for reference.

(from Luis_Coelho)
Userlevel 4
Create Date: Oct 8 2013 8:55AM

Thanks for the answer.
You're right, i won't be able to access the individual ports if they are already in a LAG.
So on each X670, i can declare one M-LAG and put the primary port of my LAG inside the M-LAG.
Globally i will have one M-LAG on each side.


Thanks for your help,
Gabriel (from Gabrielboubil)
Userlevel 4
Create Date: Oct 11 2013 4:43PM

What program did you use to make that diagram?

Thanks, (from Jeremy_Homan)
Userlevel 4
Create Date: Oct 12 2013 1:32PM


I used Microsoft Visio, and saved the diagram as a.png file for uploading.

Gabriel (from Gabrielboubil)