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    Looking a bit more explanation about the SG-3100 and STP

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    • S
      swygue
      last edited by

      As per the documentation .

      "The LAN ports do not support the Spanning Tree Protocol (STP). Two or more ports connected to another Layer 2 switch, or connected to 2 or more different interconnected switches, could create a flooding loop between the switches. This can cause the router to stop functioning until the loop is resolved."

      Does the interconnected switches mean if I have this setup: Pfsense LAN1> SW1 > SW2. This could create a flooding loop? If yes, is there another Negate device that support this config?

      Thanks

      DaddyGoD 1 Reply Last reply Reply Quote 0
      • DaddyGoD
        DaddyGo @swygue
        last edited by DaddyGo

        @swygue said in Looking a bit more explanation about the SG-3100 and STP:

        Does the interconnected switches mean if I have this setup: Pfsense LAN1> SW1 > SW2.

        Hi,

        STP is a protocol which operating in the L2 (OSI) layer and fit for larger systems (many switches).
        By calculating the best "spanning-tree" this prevents the formation of unnecesary loops. (and at the same time "backup" routes can be formed = redundancy)

        Due to the above, this can be applied in the L2 layer rather than in L3, so they do not play a role in the life of routers.

        Moreover, they can cause the problems described in the documentation.

        for example:
        When connecting a new port, the STP has a learning time interval (20 - 40 sec), and this may cause other services to time out (f.e.: DHCP)

        if you operate such networks,....
        mesh and ad-hoc networks, it may be advantageous

        So unnecessary for the -router + 2 switches- which is outlined in your case,
        rather, the physical connections should be well designed to prevent the formation of an ethernet loop

        it can be used well for understanding (interconnected switches):

        https://community.fs.com/blog/how-to-connect-multiple-ethernet-switches.html

        Cats bury it so they can't see it!
        (You know what I mean if you have a cat)

        S 1 Reply Last reply Reply Quote 0
        • S
          swygue @DaddyGo
          last edited by

          @DaddyGo thank you.

          DaddyGoD 1 Reply Last reply Reply Quote 0
          • stephenw10S
            stephenw10 Netgate Administrator
            last edited by stephenw10

            It means if you connected LAN ports 1 and 2 to the same switch you would create a loop. Unless, for example, those ports were configured as different segments via VLANs in the SG-3100.

            The internal switch that is connected to LAN ports 1-4 does not support Spanning Tree Protocol that could otherwise prevent that.

            It's not something that commonly happens, I'm not sure we've ever seen a ticket for that.

            Steve

            S 1 Reply Last reply Reply Quote 0
            • DaddyGoD
              DaddyGo @swygue
              last edited by

              @swygue said in Looking a bit more explanation about the SG-3100 and STP:

              thank you.

              You Welcome...😉

              It's just a network building question....
              The switches in the L2 layer should be allowed to work with the STP, RSTP, MSTP stuff, this should not be of interest to a switch built into a router...?!?
              (your home network does not need this)

              In a SOHO environment, a switch chip in the router may be beneficial, but then let’s not talk about STP 😉

              Cats bury it so they can't see it!
              (You know what I mean if you have a cat)

              1 Reply Last reply Reply Quote 0
              • S
                swygue @stephenw10
                last edited by

                @stephenw10 said in Looking a bit more explanation about the SG-3100 and STP:

                It means if you connected LAN ports 1 and 2 to the same switch you would create a loop. Unless, for example, those ports were configured as different segments via VLANs in the SG-3100.

                The internal switch that is connected to LAN ports 1-4 does not support Spanning Tree Protocol that could otherwise prevent that.

                It's not something that commonly happens, I'm not sure we've ever seen a ticket for that.

                Steve

                Thanks, Steve. Just so this is clear. My LAN ports 1-4 are all on the same segments. Are you saying I can connect SW1 to LAN1 and SW2 to LAN2?

                Based on @DaddyGo feedback i was going to connect SW1 to LAN1 and SW2 to SW1. I do use VLANS, so i can configure one of the LAN ports to be on it's own segment.

                DaddyGoD stephenw10S 2 Replies Last reply Reply Quote 0
                • DaddyGoD
                  DaddyGo @swygue
                  last edited by

                  @swygue said in Looking a bit more explanation about the SG-3100 and STP:

                  i was going to connect SW1 to LAN1 and SW2 to SW1.

                  I would also note that try to keep the uplink strategy, where possible use the designated port (uplink) for switches

                  https://community.fs.com/blog/switch-stacking-vs-trunking-vs-uplink-which-is-best-to-connect-switches.html

                  Cats bury it so they can't see it!
                  (You know what I mean if you have a cat)

                  1 Reply Last reply Reply Quote 1
                  • stephenw10S
                    stephenw10 Netgate Administrator @swygue
                    last edited by

                    @swygue said in Looking a bit more explanation about the SG-3100 and STP:

                    Are you saying I can connect SW1 to LAN1 and SW2 to LAN2?

                    Yes. As long as switch 1 is not also connected directly to switch 2 you will not have a loop.

                    Steve

                    1 Reply Last reply Reply Quote 0
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