NIC Teaming, also known in the Microsoft world as Load Balancing/Failover (LBFO), allows you to install additional physical Ethernet network adapters (NICs) into your server and “team” or combine them together to make one virtual NIC that provides better performance and fault tolerance. Oops—I just gave away two of my reasons for using NIC Teaming! You will need at least one adapter, which can be used for separating traffic, that is using Virtual LANs (VLANs). In order to take advantage of the LBFO benefits of NIC Teaming, you will need at least two adapters, and Windows Server 2012 will support up to 32 adapters in a single team. Wireless and Bluetooth adapters are not supported, but they won’t provide the transfer speeds you typically want to see from your servers anyway.
So let’s take a look at top five reasons for using NIC Teaming:
1. Built-in support in Windows Server 2012
If you wanted to use NIC Teaming with earlier versions of Windows Server, you would have to purchase specific network adapters from a manufacturer like Intel, then download and install addition software to create and manage the team.
With Windows Server 2012, the software component to create and manage the NIC Team is built into the OS and is available in all editions, both Server Core and Full Server versions and Hyper-V.
2. Works with any Windows Server 2012 supported NIC
I mentioned that earlier versions of Windows Server required software from the manufacturer of the NIC. This meant that you could not mix NICs in a team from two different manufacturers. This could make life difficult if you need to add or replace a NIC because the original is not available or is hard to find, and if you end up with a newer NIC, you have to worry about compatibility with the NIC Teaming software.
With Windows Server 2012, you can use NICs from any manufacturer, as long as the NIC is supported by the OS or you can find a driver that will work with Windows Server 2012. A team can be made up of all NICs from one manufacturer, or you can mix manufacturers within the same team. New NICs can be added or replaced without the fear of whether or not they’ll work with the existing software. Microsoft does not support running NICs that are rated for different speeds, but it will work most of the time. So, you will want to make sure that the NICs you plan on using all support the same transfer speeds if at all possible.
My own recommendation is to stay with the same manufacturer as much as possible to maintain a common set of drivers. I’ve always hated having to search all over the Internet for different drivers. However, I do have a team running in my lab with a combination of Realtek and Intel cards and have not had any issues.
3. Adding an NIC increases available bandwidth
If one NIC is good does that mean two is better? Well, in the case of NIC Teaming, network traffic is balanced across all active NICs, providing the ability to double your available bandwidth or more depending on the number of NICs in your server. There are some catches we need to be aware of though. There are two modes you can configure: Switch Independent and Switch Dependent.
With Switch Independent, the teaming configuration will work with any network switch. This means you can use non-intelligent switches in your network and still use NIC Teaming because all of the intelligence of how outbound traffic is distributed is managed by Windows Server 2012. The downside is that all inbound traffic is sent to only one NIC and is not distributed between all active NICs. This works great for web or FTB servers with heavy outbound traffic.
With Switch Dependent, the teaming configuration involves getting your network switches involved in the NIC Teaming configuration. Yes, you will need to configure both the switch and the host to identify which links form the team. Windows Server 2012 supports Generic/Static Teaming, where you statically configure the links, or Dynamic Teaming using a protocol like Link Aggregation Control (LACP), which dynamically identifies which links are connected between the host and switch. Both modes allow both inbound and outbound traffic to approach the practical bandwidth of the team members because the team is viewed as a single pipe. This works great for any server that has heavy inbound and outbound traffic.
4. NIC Teaming provides fault tolerance
Just by adding a second NIC and creating a team, you have fault tolerance built in. One bad card or cable does not take the remaining team members down with it. As an added bonus, if you are using Switch Independent, you can plug your team members into different switches, so if a switch goes out, you still have team members that will provide network connectivity. You can even designate a NIC as a “Standby Adapter” so that when NIC fails, cable goes bad, or a port on the switch goes out, the standby adapter becomes active and takes over the workload.
5. GUI or PowerShell?
With NIC Teaming built into Windows Server 2012, you get both. So, if you like the GUI interface with the point and click configuration or prefer the “old fashioned way” of typing in commands, Microsoft has you covered. If your preference is the GUI, you can enable NIC Teaming from Server Manager and navigate to the properties screen for the server you wish to enable and configure NIC Teaming. For you PowerShell users, you can run the Get-Command –Module NetLBFO cmdlets to see a list of 13 cmdlets that can be used to manage NIC Teaming.
Now NIC Teaming is compatible with all networking capabilities in Windows Server 2012 with three exceptions: Single Root I/O Virtualization (SR-IOV), remote direct memory access (RDMA), and TCP Chimney. For SR-IOV and RDMA, data is delivered directly to the network adapter without passing through the networking stack. Therefore, it is not possible for the network adapter team to look at or redirect the data to another member of the team. TCP Chimney is not supported because the entire network stack is offloaded to the NIC.
So, those are my five reasons or benefits of using NIC Teaming with Windows Server 2012. Now, keep in mind, NIC Teaming is not for everyone. It may require you to have intelligent switches to take advantage of all team members participating in load balancing inbound traffic. But, if you have a NIC, cable or switch port go bad, you will be able to maintain access to your server. Besides, NIC Teaming is free—sort of.