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Catalyst 3560 discards second device with same IP. Assistance needed.

Greetings. I have  one specific trouble with Catalyst 3560CG switch and Stardom reserved industrial  controller. Controller has 2 processors, one of them after(!) negotiation become  main with IP, other one stays in reserve with IP If  main one shuts down, spare one becomes main with IP This perfectly  works with DLINK and MOXA level 2 switches, but fails with Catalyst 3560,  because spare one cannot even connect to switch port. I don't know  the exact reason of it, but i suspect, that it happens because of before  negotiation both controllers have ip (i know, that it is wrong and weird, but so it goes).   First of them correctly  connects to switch port, which goes up and passes pings. Second  processor tries to connect  to switch port, which goes several times up and very soon down, then  processor lefts his tries to connect to anybody and become idle.  The switch  seems to some way check IPs of 1-st and 2-nd port packets, and shuts  down 2-nd  port. I have connected via hyperterminal and tried to disable some level 3  functions and checks of the switch, but this wasn't helpful. Cannot anybody tell me  how exactly(or at least approximately) should i configure a switch to make this  bundle work? Thanks.

P.S. Excuse me for  my poor English, it's foreign for me =).
1 Reply 1

Rising star
Rising star


In their default configuration Cat3560 ports are L2 only (ie. switchports) and as such unaware of IP addressing scheme.

Will you please try to configure interfaces (ports) connected to Stardom via the "switchport host" command. This command is actually a macro which optimizes ports for a host connection.

BTW: When talking about the Stardom controller are you referring to the FCN type, and if yes are you trying to set up the "single network, double CPU" type of connection?

Best regards,


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