I have one organization which have about 1000 systems.we have one manageable switch and many unmanageable switches.all our computers are connected to un manageable switches and unmanageble switches are connected to manageable switch.My manageable switch is connected to providors switch.In peak usage the switch ports on providor are get fequently blocked.Pls give me solution to prevent ports blocking problem.
Could you clarify what you mean by your ports getting "blocked"? They stop working? Traffic on them gets dropped? You are getting high retransmission counts? You are getting transmisions dropped because they encounter more than 16 collisions?
Is it only the switch port connected to your ISP that you are having difficulty with? Or are you having problems also with "in-house" traffic that is going through your core managed switch as a step in getting between your unmanaged switches?
Have you used MRTG or Whats Up! (or the command line) to examine the traffic patterns of your ports and to examine the error statistics? Have you examined the traffic patterns in order to find out what kind of data is responsible for the bulk of the traffic? Have you checked to be sure that the traffic is related to the purposes of the organization -- that, for example, people are not loading your network by listening to internet radio stations or watching unnecessary video clips? Have you checked to be sure that your network isn't ending up being a Skype or P2P sharing node?
My initial hypothesis is that since you have 1000 systems and only one of your switches is managed, that likely you are using old equipment that is not fast enough for your organization's needs. Possibly also your internet connection is slower than your organization needs. It would not surprise me if it turned out that a number of your users are using the network for unnecessary traffic: it does not sounds as if you have the infrastructure in place to do much monitoring, and when people know they are not being monitored, there is always a temptation to "just listen to a bit of music" or something similar.
You have 1000 computers connected in a single layer 2 configuration? Sounds like a spanning-tree issue. Routers/Layer 3 switches were invented to fix this problem. I would bet that somewhere on your network, at LEAST one of the switches can't handle the spanning-tree traffic because you layer 2 network is too big. Diagnosing this problem is pretty much impossible using unmanaged switches.