How to use Managed switch and UN managed switch in a same network.

BadriMS07 · ‎01-09-2021

I'm facing issue in designing network for our machinery. We have 16 No's of machine connected to single UN managed HUB. If HUB failure happens we are facing communication issue and losing our production due to damaged products. Without server communication our machines function will not work. In every machine have Programmable logic controller & Human machine interface. I am planning to change into Rapid spanning tree protocol network from linear topology to avoid communication loss due to HUB failure.

Joseph W. Doherty · ‎01-09-2021

I suspect what you're trying to accomplish is to avoid a single point of (L2) failure. Unclear you'll be able to (re)use your un-managed switch as part of a solution.

Using two managed switches that support RSTP, and assuming the hosts connecting to them support RSTP too, might provide the redundancy you desire. Or, using two managed switches in a stack configuration (which creates one logical switch) and having your hosts have a link to both, might also work for you too. The latter, might also be done using a STP protocol between the switches and hosts, or having the hosts have LACP (Etherchannel) links across the stacked switches.

Some hosts support other redundancy approaches, besides STP (rare I suspect) or LACP (more likely).

Richard Burts · ‎01-10-2021

I am confused about this post. The original environment is described as 16 machines connected to a hub. But then there is mention of Rapid Spanning Tree Protocol. And ultimately the question asked is about an unmanaged switch and a managed switch.

What happened to the hub? What is the logic for replacing a hub with both a managed switch and an unmanaged switch? If it was 16 machines connected to a hub then I would think an unmanaged switch would be an adequate solution. I could also understand if the decision was that while upgrading the network it was worth it to get a managed switch instead of an unmanaged switch. But what is the logic for replacing a hub with 2 switches?

But since the question asked was about implementing 2 switches, one managed and one unmanaged let me answer that question. The unmanaged switch does not have the ability to create vlans, so all of the ports/interfaces on the unmanaged switch will be in a single vlan. It would make good sense to connect one of the ports on the unmanaged switch to an access port of the managed switch. Initially it would simplify things if the managed switch configured a single vlan (hopefully something different from vlan 1) and assigned all of its ports as access ports in that vlan. As the network grows it might make sense for the managed switch to configure additional vlans, and perhaps to configure an interface as a trunk to connect to some upstream device that would provide routing between the vlans.

HTH

Rick

BadriMS07 · ‎01-10-2021

Kindly check into the attachment. You may get a idea why I'm asking for usage of two switches.

We connected all our machines to server through hub. In case any communication loss found between server and machine plc. Within 1min communication need to be restored otherwise,all machine operation will stopped. Due to that we are facing large production loss.

To avoid production loss I'm planning to make the network in a redundant .

Kindly find the existing network, new planning networks routing as per the attachment. Kindly suggest which network will provide Redundant to avoid communication loss in between machines.