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Hyper-V Network Adapters Legacy vs. Virtual
Hyper-V Network Adapters Legacy vs. Virtual
- This is more a curious question. I looked around for the answer, but couldn't find specifics. I currently have a Windows 2008 R2 Enterprise server setup hosting Hyper-V. Currently I have only 1 VM (Windows 2008 R2 Standard) installed. It seems I can ONLY get network connectivity by using the Legacy adapter and NOT the regular Network Adapter for the setup of the VM. The question is, am I LOSING anything by using the Legacy adapter or am ok by using it? And I have setup the Integration Services, and still had no luck being able to use the regular Network Adapter for the VM.
Answers
- The "Network Adapter" is also known as the synthetic network adapter. It working 100% is dependant upon the Integration Components of the Host and the VM matching. This is generally accomplished by installing the "Integration Services" into the VM.
Beginning with Server 2008 and Vista (some service pack) these have been built into the OS. And they are either updated through patches or through again installing them into the VM through the VM console.
The real fun begins when Server 2008 (Hyper-V v1) and Server 2008 R2 (Hyper-V R2) get combined. The newer can support the older, but the older cannot support the newer. So a strange mish-mash of incompatibility begins.
Now, you ask if you are losing anything by using the "Legacy Network Adapter"
The technical answer is yes.
The Legacy adapter is emulated therefore it requires greater host overhead, additional data hand offs between each layer - and thus the potential throughput is lower.
Contrast this with the Synthetic adapter - this virtual network adapter is actually 'closer' to the physical adapter and can take advantage of some features of the physical adapter - thus allowing some of the processing work to move away from the Hyper-V hypervisor and into the NIC hardware itself. Also fewer data hand-offs because of fewer layers. Thus a higher potential throughput.
Now for the big question: Will you notice a throughput difference? Possibly.
Whether or not you experience a difference between the two depends on the applicaitons being run and frankly their amount of traffic on the network. The higher throughput required the greater the difference.
In your case - of both your Host and your VM are Server 2008 R2 (regardless of any flavor) and they are both at the RTM (release) level - then they 'should just work'. The only way they wouldn't is if they are not both at the RTM level, or one has installed a Hyper-V patch that is newer than the other (and I don't beleive that there have been any patches fr Hyper-V R2 yet).
Does that help?
Brian Ehlert (hopefully you have found this useful)- Marked As Answer byKeith D. Thursday, November 05, 2009 4:23 PM
All Replies
- The "Network Adapter" is also known as the synthetic network adapter. It working 100% is dependant upon the Integration Components of the Host and the VM matching. This is generally accomplished by installing the "Integration Services" into the VM.
Beginning with Server 2008 and Vista (some service pack) these have been built into the OS. And they are either updated through patches or through again installing them into the VM through the VM console.
The real fun begins when Server 2008 (Hyper-V v1) and Server 2008 R2 (Hyper-V R2) get combined. The newer can support the older, but the older cannot support the newer. So a strange mish-mash of incompatibility begins.
Now, you ask if you are losing anything by using the "Legacy Network Adapter"
The technical answer is yes.
The Legacy adapter is emulated therefore it requires greater host overhead, additional data hand offs between each layer - and thus the potential throughput is lower.
Contrast this with the Synthetic adapter - this virtual network adapter is actually 'closer' to the physical adapter and can take advantage of some features of the physical adapter - thus allowing some of the processing work to move away from the Hyper-V hypervisor and into the NIC hardware itself. Also fewer data hand-offs because of fewer layers. Thus a higher potential throughput.
Now for the big question: Will you notice a throughput difference? Possibly.
Whether or not you experience a difference between the two depends on the applicaitons being run and frankly their amount of traffic on the network. The higher throughput required the greater the difference.
In your case - of both your Host and your VM are Server 2008 R2 (regardless of any flavor) and they are both at the RTM (release) level - then they 'should just work'. The only way they wouldn't is if they are not both at the RTM level, or one has installed a Hyper-V patch that is newer than the other (and I don't beleive that there have been any patches fr Hyper-V R2 yet).
Does that help?
Brian Ehlert (hopefully you have found this useful)- Marked As Answer byKeith D. Thursday, November 05, 2009 4:23 PM
- Hi,
try to search emulated vs synthetic network adapter. here is one of the site which explain about the different.
http://trycatch.be/blogs/roggenk/archive/2008/11/04/hyper-v-and-virtual-devices-vdev-synthetic-versus-emulated-devices.aspx
By right, you should get Synthetic device when the VM is running Win 2k8 R2.
try again without network teaming / upgrade your BIOS/driver.
laiys Hi,
I think BrianEh had provided the most helpful information.
By the way, I have a post discussed the similar issue with yours, you can refer to:
Network Adapter (not Legacy) does not work on Virtual Machine after installation through ISO
Vincent Hu
- That is a great informative answer. Thank you for the in-depth response. I will possibly try and test server and install from scratch again and see if I get get it to see it like it should. I will re-download the ISO, as that is how I was installing it. Could possibly be the issue. Thanks again for the information.
- I will check that post out. Thanks!
