How to recover from switch failure? [closed]

Suppose there is only one switch within a system and it is connected to a bunch of machines to form a network. If this switch goes down, the entire network goes down. Chances of this happening are unlikely. I would like to know... what are the ways to increase the availability of these machines?

Would I need to have a second switch connected to each machine (so each machine needs 2 network adapters)? Or could I somehow obtain a switch that is able to failover to another backup switch? Is there other recommended ways to do this?

Thank you for your guidance.

You will need the multiple NICs in each box and the two switches, with each box plugged into both switches. Then setup NIC Teaming/NIC Bonding.

For most modern operating systems it is a pretty simple setup, and in most basic environments it will just work. In Windows Server 2012 you have to use Switch Independent mode and the OS will take care of everything.

Assuming Windows Server 2012:

• In Server Manager click Local Server.
• Click Disabled next to NIC Teaming.
• In the Teams area, click Tasks - New Team.
• Provide a name for the NIC Team.
• Choose the adapters you want to add to the team.
• Default settings under Additional Settings should be fine. If you have trouble you can try changing the Load Balancing Mode.

You have just created a logical interface that contains the other physical interfaces. Now you can provide the Team interface an IP, Default Gateway, etc. just like you would any network interface.

Very interesting question. The more I think of an answer to this problem them more road blocks I am hitting.

Here is a few possible solutions that I can think of:

Two NICs in Each Machine + Two Switches

This is obviously what you suggested but you might run into problems with each computer on your network taking 2 IP address's. What I would suggest for this scenario is to have the computers connected to both switches but make sure you only have one switch on at a time. So if one fails you can manually flick the second switch on with minimum down time.

Problems:

• You'll have to remember to keep a copy of any changes made to the config of the first switch so you can duplicate them on the second switch.
• Someone in the know will have to be physically present to do the change over.

Keep a Spare Switch

If you are going to have two swtiches, instead of going through the effort of buying a second NIC for each computer and then running the cable, just keep a spare switch that has the exact config. You could easily rack mount it or sit it on top of the production switch. If the switch goes down, just unplug one port at a time from faulty switch to backup switch.

Problems:

• If you have tons of computers on the network this may take a long time, or not be possible space wise
• You'll have to remember to keep a copy of any changes made to the config of the first switch so you can duplicate them on the second switch, or make the changes on both
• Someone will have to be present to do the change over

Failover Switching

This is much more complicated than the above but companies like Cisco have Failover features on some switches. I would images you would have to get the right switches that support it. Have a read of these links:

• Configuring Failover Cisco
• Switch Failover HP

This stuff is over my head but might give you some ideas.