Announcement

Collapse
No announcement yet.

Switch redundancy

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Switch redundancy

    Hello,

    I am studying some networking theory on my own and thought of this issue:

    If I had a four story building, a switch in each floor, and they are connected to each other through two different trunk links to make them redundant, but...what if the switch in the third floor fails?.

    Shouldn't I have an alternative path to go from the second floor to the fourth ?.

    Similarly, if the switch in the second floor goes down, shouldn't I have an alternative way to go from first to third floor ?.

    It is a real life scenario ?

    thanks in advance.
    Last edited by loureed4; 5th August 2015, 09:32.
    -
    Madrid (Spain).

  • #2
    Not sure if it's a real life scenario. Do you have a diagram you could post?

    It could work if things were connected properly and spanning-tree was enabled. In my real life scenarios I've run multiple links from the IDFs to the MDFs and had the HA switch or switch stack and configured LAGs to the IDFs. That way we get performance and redundancy. But there are may ways to configure things and it really depends on the requirements and the budget.
    Regards,
    Jeremy

    Network Consultant/Engineer
    Baltimore - Washington area and beyond
    www.gma-cpa.com

    Comment


    • #3
      Thanks JeremyW.

      Yes, I am studying Spanning tree protocol, therefore, between the switches I think that is mandatory, or at least very advisable.

      I have all the switches connected as follows: The one in the first floor with the one in the second , the one in the second to the one in the third floor, but my point was: What if the one in the second or third floor goes down?.

      In my view, putting a direct cable going from the one in the first floor to the one in the third floor , and another direct cable from the second to the fourth would help out if either the second or the third switch went down.

      I am not much of an expert, then I did not understand: IDFs, MDFs, LAGs and IDFs. Well, at least I understood HA (High availability)
      -
      Madrid (Spain).

      Comment


      • #4
        MDF and IDF are terms used to describe the network layout, so to speak. An MDF is a Main Distribution Frame that "distributes" network connectivity to IDF's, which are Intermediate Distribution Frames, which "distribute" network connectivity to end points. Neither MDF or IDF are technical aspects in the sense that they aren't things to be configured.

        All that being said, you definitely need to be running STP in your switches and you should setup redundant paths throughout the network in order to insure network connectivity in the case of any single switch failure. From a cursory standpoint, connecting 1 to 2, 2 to 3, 3 to 4, 1 to 3 and 2 to 4 would seem to give you enough redundant paths that if any one switch failed connectivity would remain intact between the remaining 3 switches.

        Additionally, I find the best way to visualize a network is to draw it out on a piece of paper. It helps you to better see the network paths, possible points of failure, switch loops (which STP will take care of), etc.

        Comment


        • #5
          That was really helpful joeqwerty. Thanks a lot!
          -
          Madrid (Spain).

          Comment


          • #6
            Joe pretty much explained everything.

            You did ask about LAGs which stands for Link Aggregation Group. It is where you combine multiple switch links to act as one. So if you have a LAG of four 1G ports connecting two switches, you will have 4G of bandwidth between the two.
            Move info: http://en.wikipedia.org/wiki/Link_aggregation
            Regards,
            Jeremy

            Network Consultant/Engineer
            Baltimore - Washington area and beyond
            www.gma-cpa.com

            Comment


            • #7
              Thanks a lot JeremyW!
              -
              Madrid (Spain).

              Comment

              Working...
              X