cross-posted from: https://lazysoci.al/post/12597342

Okay, I’ve been watching lots of YouTube videos about switches and I’ve just made myself more confused. Managed versus unmanaged seems to be having a GUI versus not having a GUI, but why would anyone want a GUI on a switch? Shouldn’t your router do that? Also, a switch is like a tube station for local traffic, essentially an extension lead, so why do some have fans?

  • Brownian Motion
    0•5 months ago

    Firstly Its not cat 3. I’ve never seen that in a telephony installation. Its 4 core flat ribbon or just 4 core. Neither are twisted. Secondly, with 2 “pairs” the best you can do is 100mb/s, as in 10MB/s. Thirdly an L3 Switch DOES use the L3 protocol stack - that is where ROUTING and the routing table happens. OSPF, EIGRP, RIPv2, IS-IS, BGP are all LAYER 3 protocols.

    I think you need to go back to school.

    https://en.wikipedia.org/wiki/Open_Shortest_Path_First

    OSPF is a layer 3 protocol. If a layer 2 switch is between the two devices running OSPF, one side may negotiate a speed different from the other side. This can create an asymmetric routing on the link (Router 1 to Router 2 could cost ‘1’ and the return path could cost ‘10’), which may lead to unintended consequences.

    • @mitchconnor
      0•5 months ago

      I like how we are arguing over old stuff that basically doesn’t matter. Do you want to also mention token ring for an achtually statement?

      Cat 3 cable can be used in telephony as referenced here https://en.wikipedia.org/wiki/Category_3_cable but it kind of really doesn’t matter for the original poster does it?

      You are right that switches can operate at L3 if you have an L3 switch. You can also disable it and make it into this lobotomized brick that just forwards packets based on the CAM table. Guess what layer that operates at? Guess what protocols literally don’t matter for forwarding packets that are on the same L2 network?

      @bigredgiraffe is pointing out the distinction between L2 and L3 devices within a network for someone that is learning networking. He is making the clear distinction that NEEDS to be made for someone learning. Not all switches are layer 3, not all switches have layer 3 enabled because they have the feature set, not all networks are created equally.

      Maybe instead of helping this guy learn about the distinction between layers, justifications, etc. you can just tell him every switch is L3, uses an overlay, and runs 3-5 routing protocols all redistributing routes to other overlays.

      • Brownian Motion
        1•5 months ago

        I was networking AUI, before you were born, numb nuts.