× NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Orbi WiFi 7 RBE973
Reply

How stacking works is 2 stacked switches?

MotivIT
Aspirant

How stacking works is 2 stacked switches?

Hi Experts,

I'm new to stacking and I would like to know how it will work with 2 switches.  I know that when these 2 switches were stacked, they basically become a single switch.  Now my question is, how High Availability is achieved by this?  For example, Switch 1 has 40 devices connected to the ethernet ports.   Then 35 devices connected to the ethernet ports of Switch 2.  When one of them goes down, how the remaining Switch can cater all the devices connected to the Switch that goes down?  Can someone shed me some light of concept and what will happen in this scenario?

Thanks in advanced!
Arnel

Model: GS748TS|ProSAFE Gigabit Stackable Smart Switch|EOL
Message 1 of 7

Accepted Solutions
Hopchen
Prodigy

Re: How stacking works is 2 stacked switches?

Hi,

 

If device A is connected to switch A, and switch A dies - well then device A will loose access to the network.
If device A is connected to switch A, and cable between them fails then device A will loose access to the network.

 

There is nothing you can do to prevent this and that is OK because high availability is not about end devices. It is about creating a resilient network to allow important devices to have high availability. Devices such as: servers, storage devices, switches, routers, etc.

A common way to create this high availability is through a combination of stacking and LAG (bonding). For example: I have a stack of two switches. I connect a server to the stack. The connection a done via a LAG of two cables, so that:
- One cable is going from the server to switch 1 in the stack.
- The other cable is going from the server to switch 2 in the stack.

 

This is called making a LAG across the stack. This is possible to do as the switches in the stack are acting as one unit (like you mentioned yourself). Now, your server has high availability. If switch 1 in the stack dies, the server will still have connection to the network via switch 2. Same scenario if one of the cables fail. This high availability becomes even higher if you stack, say 4 switches, and then then make a 4 cable LAG (across the stack) to your server.

 

Now, all of this requires two things:
1. The device that connects to the stack is capable of configuring LAGs.
2. That the device connecting to the stack has several NICs.

 

End devices only has one entry point to the network. If that entry point fails (cable failure or switch failure) then that end device will loose connection. There is nothing you can do about that. If the device is really important, be sure to make LAGs and connect to a stack if possible.


I hope that answered your question.


Cheers

View solution in original post

Message 5 of 7

All Replies
JohnC_V
NETGEAR Moderator

Re: How stacking works is 2 stacked switches?

Hi MotivIT,

 

Welcome to the community!

 

Yes, we can stack 2 switches. The only advantage in using a stack is that you only have 1 management page. Once the 1st switch or the 2nd switch goes down, the network will still be up and running but only 1 switch will be left. You should have a redundancy from the uplink just in case that one of the switches will go down.

 

Regards,

Message 2 of 7
JohnC_V
NETGEAR Moderator

Re: How stacking works is 2 stacked switches?

@MotivIT,

 

I would like to have a follow up on this thread. Please let us know if you still need further assistance and just in case that the reply would be the answer to your issue. I encourage you to mark the appropriate reply as the “Accepted Solution” so others can be confident in benefiting from the solution. The NETGEAR Community looks forward to hearing from you and being a helpful resource in the future!

 

Regards,

Message 3 of 7
MotivIT
Aspirant

Re: How stacking works is 2 stacked switches?

Hi,

 

My question is still unanswered.  I know High Availability can be achieved but how exactly?   For example, Switch 1 (48 port) has 40 devices connected to the ethernet ports.   Then 35 devices connected to the ethernet ports of Switch 2 (48 port).   40 + 35 = 75 devices.  Lets say Switch 1 went down.  How will Switch 2 can serve all the connected devices to Switch 1?  Or how it can serve all 75 devices where it only has 48 ports?  What will happen in this case?

 

Thank You!

 

Arnel

Message 4 of 7
Hopchen
Prodigy

Re: How stacking works is 2 stacked switches?

Hi,

 

If device A is connected to switch A, and switch A dies - well then device A will loose access to the network.
If device A is connected to switch A, and cable between them fails then device A will loose access to the network.

 

There is nothing you can do to prevent this and that is OK because high availability is not about end devices. It is about creating a resilient network to allow important devices to have high availability. Devices such as: servers, storage devices, switches, routers, etc.

A common way to create this high availability is through a combination of stacking and LAG (bonding). For example: I have a stack of two switches. I connect a server to the stack. The connection a done via a LAG of two cables, so that:
- One cable is going from the server to switch 1 in the stack.
- The other cable is going from the server to switch 2 in the stack.

 

This is called making a LAG across the stack. This is possible to do as the switches in the stack are acting as one unit (like you mentioned yourself). Now, your server has high availability. If switch 1 in the stack dies, the server will still have connection to the network via switch 2. Same scenario if one of the cables fail. This high availability becomes even higher if you stack, say 4 switches, and then then make a 4 cable LAG (across the stack) to your server.

 

Now, all of this requires two things:
1. The device that connects to the stack is capable of configuring LAGs.
2. That the device connecting to the stack has several NICs.

 

End devices only has one entry point to the network. If that entry point fails (cable failure or switch failure) then that end device will loose connection. There is nothing you can do about that. If the device is really important, be sure to make LAGs and connect to a stack if possible.


I hope that answered your question.


Cheers

Message 5 of 7
MotivIT
Aspirant

Re: How stacking works is 2 stacked switches?

Exactly the answer I was looking for.  Thanks for the brief and concise explanation, Hopchen! 

Message 6 of 7
Hopchen
Prodigy

Re: How stacking works is 2 stacked switches?

No worries at all. Happy to help 🙂

Message 7 of 7
Top Contributors
Discussion stats
  • 6 replies
  • 7054 views
  • 1 kudo
  • 3 in conversation
Announcements