Dual NIC question for a networking idiot

[Jeffman]

Hey,

I'm looking at going to a dual NIC setup at work. This would be 100% for redundancy, nothing else. One NIC would go to one switch, and the other NIC going to a backup switch in case of failure or power outage

Do I need to get a dual interface card, or can I just get another random NIC and install it?
Do I need to do a team, or can I just do a primary/secondary setup?
Is there anything else I should know?

I'm OK at networking, just by no means a master. My work has a 3rd party we hire our network admin functions out to, I just would prefer to do this myself. I know how to do most of it, including set up a team of NICs. I just don't know what the best option is for redundancy.

TIA

 

[GotNoRice]

Two independent network cards is fine. There are also cards like the Intel Pro/1000 PT dual-port adapter that you can get very cheap on eBay these days if you wanted to go the dual-port route.

You don't need to do teaming, unless you want or need both interfaces to share the same IP address. That can make it easier if you have certain ports manually mapped to your computers IP address via your router, but with most things using UPNP (which can map ports automatically as needed) you don't usually have to worry about that much anymore. If you are okay with each interface having a separate IP then it doesn't matter.

What is nice is that Windows 10 and later versions of Windows Server will use all of your network connections simultaneously when doing transfers, even without teaming. I have 3 network cards in both my main PC and my file server and I can transfer files between them at up to 3Gbps. No setup required, it just works, as long as all ports are connected to the same network (even if not the same switch, though that may create other bottlenecks).

 

[ComputerBox34]

Two independent network cards is fine. There are also cards like the Intel Pro/1000 PT dual-port adapter that you can get very cheap on eBay these days if you wanted to go the dual-port route.

You don't need to do teaming, unless you want or need both interfaces to share the same IP address. That can make it easier if you have certain ports manually mapped to your computers IP address via your router, but with most things using UPNP (which can map ports automatically as needed) you don't usually have to worry about that much anymore. If you are okay with each interface having a separate IP then it doesn't matter.

What is nice is that Windows 10 and later versions of Windows Server will use all of your network connections simultaneously when doing transfers, even without teaming. I have 3 network cards in both my main PC and my file server and I can transfer files between them at up to 3Gbps. No setup required, it just works, as long as all ports are connected to the same network (even if not the same switch, though that may create other bottlenecks).

I have not heard of this before. If you are trying to transfer one 50 gb file, how is windows able to take advantage of both NICs with two source IPs and one destination?

What happens when you are not in the same Layer 2 segment as your server - how does Windows figure out which NIC to use to route the traffic? (Windows has historically been HORRIBLE in figuring this out)

The only way I see those kind of scenarios working is with LACP (or "bonding") and a single IP address.

In OP's case, your setup should work however if the primary NIC fails, you will experience an interruption in traffic while you wait for Windows to figure it out and switch to the backup by modifying the local route table.

If OP wants no interruptions in traffic, you have two options:

• Setup local LACP or straight ether channel bond on PC. Connect PC to two different switches in the same logical switch stack (shared management plane) and create the LACP or etherchannel bond at switch level
• If the switches do not share the management plane, you will require MC (or multi chassis) LAG. In Cisco's world, this requires VPC functionality which is only supported on Nexus data center switches AFAIK. Arista uses MLAG. Highly doubt you will find this sort of gear in an office.

 

[GotNoRice]

I have not heard of this before. If you are trying to transfer one 50 gb file, how is windows able to take advantage of both NICs with two source IPs and one destination?

SMB Multichannel, supported in SMB 3.0 and above. A single session is broken down into multiple TCP/IP connections. That also allows for better CPU utilization (multiple TCP/IP connections can spread out among multiple CPU cores) and automatic fault tolerance since unplugging any individual NIC won't interrupt the file transfer. It's not super-new either, as it's been supported since Windows 8.1 and Windows Server 2012.

https://blogs.technet.microsoft.com...a-feature-of-windows-server-2012-and-smb-3-0/

 

[Jeffman]

Thanks, I think I can make sense of that info. I really need to learn more about networking.

No, I don't want interruptions at all. Even very minor interruptions we have seen in the past when power goes out and we switch from primary to secondary firewalls have caused our software to lose server access and crash. It's finicky software.


I do need to share the same IP address if possible. So it sounds like I'll need a team. I just wanted to make sure I could team 2 different NICs without problems. I considered just buying some PCI X4 server cards to throw in, I'm sure they'll work.

 

[ComputerBox34]

SMB Multichannel, supported in SMB 3.0 and above. A single session is broken down into multiple TCP/IP connections. That also allows for better CPU utilization (multiple TCP/IP connections can spread out among multiple CPU cores) and automatic fault tolerance since unplugging any individual NIC won't interrupt the file transfer. It's not super-new either, as it's been supported since Windows 8.1 and Windows Server 2012.

View attachment 190869

https://blogs.technet.microsoft.com...a-feature-of-windows-server-2012-and-smb-3-0/

This would only work for SMB only though - nothing else, correct?

Thanks, I think I can make sense of that info. I really need to learn more about networking.

No, I don't want interruptions at all. Even very minor interruptions we have seen in the past when power goes out and we switch from primary to secondary firewalls have caused our software to lose server access and crash. It's finicky software.


I do need to share the same IP address if possible. So it sounds like I'll need a team. I just wanted to make sure I could team 2 different NICs without problems. I considered just buying some PCI X4 server cards to throw in, I'm sure they'll work.

Make sure whatever card you buy supports LACP and has multiple interfaces. 802.1q vlan tagging may be handy as well depending on what you do day to day.