Connecting zyxel switches guide?

Lorcan

Can anyone tell me what the best way to connect four zyxel switches are.

On one side of the building is a GS1920-24 and a GS1920-24HP

the other side is the same (4 in total, 2 on each side)

Lets say SW1 = GS1920-24, SW2 = GS1920-24HP, SW3 = GS1920-24, SW4 = GS1920-24HP

The person previous to me had it set up like this:

• SW1 connects to SW2 (1 foot fibre)
• SW1 connects to SW3 (fibre goes across the building)
• SW2 connects to SW4 (fibre goes across the building)
• SW4 connects to SW3 (1 foot fibre)

So each switch has two of its SFP fibre ports used. In total there are 8 ports used. There are 4 connections.

However this led to some kind of crazy broadcast loop or something happening (I think), the entire network went crazy, it even started causing laptops and PCs to lag and act funny, which is something I didnt know was possible.

As such I disconnected the fibre SFP link between SW1 and SW2. I also disconnected the link between SW2 and SW4. Now:

• SW1 connects to SW2 (1 foot ethernet)
• SW1 connects to SW3 (fibre goes across the building)
• SW4 connects to SW3 (1 foot fibre)

This stopped the broadcast loop which was going crazy.

I am just wondering though, what is the correct way to connect switches together via fibre.

I remember seeing some diagram where it said you must connect for example SW1 SFP port 27 → SW2 SFP port 28, then SW1 port 28 → SW2 port 27. I think it said you cant connect SFP port 27 on one switch to SFP port 27 on the other? Does anyone have that diagram..

Zyxel_Melen

Hi @Lorcan,

The person previous to me had it set up like this:

• SW1 connects to SW2 (1 foot fibre)

• SW1 connects to SW3 (fibre goes across the building)

• SW2 connects to SW4 (fibre goes across the building)

SW4 connects to SW3 (1 foot fibre)

According to the description, it seems like your network is a ring topology. In a ring topology, you have to set up RSTP to prevent loops.

Please reference this FAQ to configure RSTP:

https://community.zyxel.com/en/discussion/3004/how-to-configure-rstp-in-a-ring-topology-v4-70-or-previous-version

https://community.zyxel.com/en/discussion/19756/how-to-configure-rstp-in-a-ring-topology-v4-80-version

Zyxel_Melen

Hi @Lorcan,

The person previous to me had it set up like this:

• SW1 connects to SW2 (1 foot fibre)

• SW1 connects to SW3 (fibre goes across the building)

• SW2 connects to SW4 (fibre goes across the building)

SW4 connects to SW3 (1 foot fibre)

According to the description, it seems like your network is a ring topology. In a ring topology, you have to set up RSTP to prevent loops.

Please reference this FAQ to configure RSTP:

https://community.zyxel.com/en/discussion/3004/how-to-configure-rstp-in-a-ring-topology-v4-70-or-previous-version

https://community.zyxel.com/en/discussion/19756/how-to-configure-rstp-in-a-ring-topology-v4-80-version