I am working in an institute where the internet connection is divided amongst 3 different floors: Ground Floor, First Floor and Second Floor. Now since I am new to the networking, I know the essentials.

There are two different internet connections of same company BSNL. So we call them as BSNL-A & BSNL-B.

Now here, LET ME TELL ONE THING. THERE IS NO SINGLE ROUTER IN CAMPUS. THE MODEMS (not routers) of two connections respectively BSNL-A & BSNL-B are connected directly to the switch and there onwards the connection is distributed amongst various computer terminals.


BSNL-A has gateway & BSNL-B has gateway

Now the main issue is, when we turn ON both the switches & both the modems BSNL-A & BSNL-B modems, the internet connection work with ip assigned by one of BSNL-A & BSNL-B modems uptil some time. But later this creates conflict and the shared folders doesn't get accessed and there is yellow exclaimation mark on network adapter symbol. Both the connections BSNL-A & BSNL-B are active.

What is the solution to this? I want to keep both the ISP modems active and connected to the switch all the time and also want to keep the folder sharing unaffected despite the ip assignment gets changed automatically. All the IPs currently are assigned automatically.

Please guide me about the solution on this.

  • 2
    Assuming DHCP is also served by the BSNL-A/B routers, both DHCP scopes seem to be clashing and need to be sorted out. You definitely require a decent, central router. Are the switches managed or "dumb"?
    – Zac67
    Commented Feb 22, 2019 at 7:26
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Commented Dec 14, 2019 at 20:32

1 Answer 1


To expand on @Zac67 's comment, you will need to purchase a router to direct traffic to each modem, as well as be a single source for DHCP. This may require reorganizing your network switches, depending on where the physical connections are located.

I should point out that it is difficult to distribute traffic across both modems. Generally one ISP connection will be used, and the other will serve as a backup connection in case the first one fails.

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