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Cisco SG550 Switch Stack Cable Configuration and Troubleshoot

Hi Team, 

        I have two Cisco SG550 switches in Core Layer. I have connected this two switches with using Stack Cable.

        This two switches uplink connection connected with Access layer switches

        When i down the one uplink port connection from one core layer Cisco SG550 switch after that also my data traffic can pass internally fine and via firewall WAN network also working fine

      While i am power down one switch and trying to get data traffic from another switch power switch its working 

      Internal network working fine but Firewall ip address is not reachable i am unable to access WAN 

Why this happened 

Is that i need to configure any extra Commands, or else what should i do for another switch also get data traffic 

please help me to complete my setup 

my core layer one switch up link connection is connected with Firewall another switch connection is not connected with firewall - Only one uplink between firewall and Stack able two master switch not with switch 

or else i need to give two uplink connection ? between firewall - cisco SG550- Cisco SG550 switch 


My topology is as below

cisco SG550 - CIsco SG550 --->Firewall port

switch <--->  Switch ----> Firewall  ( one uplink connection between switch and firewall )


after power down one switch i am unable to get WAN traffic inside the LAN.

Two switches connected with Stack Cable.


Is that I need to do any configuration or any setup change pls help to complete 




Georg Pauwen
VIP Master



post a schematic drawing of your topology including all devices and how they are connected.

@Georg Pauwen wrote:



post a schematic drawing of your topology including all devices and how they are connected.

HI Georg Pauwen

              Please find the Attached Document for your reference. 



judging from your drawing, you only have one physical connection from the SG550 to the Firewall ? If that is the case, powering of any of your SG550 switches will result in the firewall to become unreachable. The purpose of stacking is not to provide redundancy for external connectivity, but rather to ease management, and to expand capacity.


What exactly are you trying to accomplish, a redundant link to the Firewall ?

How do i remove interface Port-Channel1 configuration from My cisco SG550 switch
i am unable to delete it
i try to delete in global configuration mode, as
(config)# no interface Port-Channel1
but its not deleting
paul driver
VIP Expert


If i have your topology correct - your core switch(s) even though they are stacked only has one physical connection into the firewall and when that switch drops and the fw port you then dont have any direct path to the firewall.

So you need to either aggregate two ports (one from either switch) into the firewall or just have two access ports connected to the firewall and have one running as a backup to the other

Please rate and mark as an accepted solution if you have found any of the information provided useful.
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Kind Regards

Hi paul driver,
As you say, Even i am also plan to do LacP Configuration in my switch for two switches logically act as a single switch,
Can u share me the LACp Configuration for CIsco SG550 switch with troubleshoot commands.
Already i have configured LACP configuration on my switch but i need confirmation for my setup
Kindly share me the LACp configuration commands, so that it will be easy to my complete my setup.
How do i check that my LAC configuration enabled on particular interface or not ?

Yasmeen Shaul Hameed.

Hi Team,

          After Configuring LacP Configuration on my cisco SG550 Switch i am getting following Error,

Po1 Active: gi1/0/1 Non-candidate: gi2/0/1

How do i Troubshoot it


My Set up like below 


sg550 <----> SG550