Virtually Prepared

…leaving your physical world virtually behind

Browsing Posts tagged nic

Having built a Windows 2003 or Windows 2008 virtual machine you realise the network adapter type isn’t the preferred model. After powering down, removing and adding a new adapter you’re unable to apply the IP address to the new NIC.

You’re presented with this friendly message, “The IP address x.x.x.x you have entered for the network adapter is already assigned to another adapter…”.

[The screenshot below explains]

IP address assigned to an orphaned adapter


What should I do about this?

Simple, you should remove the ‘missing’ adapter and here’s how.

  • Login with an account that has Administrative rights.
  • Open a Command Prompt.
  • Type set devmgr_show_nonpresent_devices=1
  • Type start compmgmt.msc

[The screenshot below shows the commands]

Environment variable to reveal more 'Hidden' devices

  • In the Computer Management MMC expand out the Device Manager branch.
  • Expand out the Network adapters branch.

[The screenshot below explains]

A single NIC, where's the other?

  • On the MMC toolbar click View
  • Select Show Hidden Devices

[The screenshot below explains]

Show Hidden Devices

  • Looking in the Network adapters category now you should notice a few devices appear

[The screenshot below explains]

As if by magic, the missing NIC appears.

You’ll notice the orphaned adapter is ‘greyed out’.

  • Right-click the greyed out adapter and select Uninstall.

[The screenshot below explains]

Remove the redundant entry

  • Close the Computer Management MMC and Command Prompt windows.
  • Well done.

During a recent Q&A session regarding a HP Blade implementation (BL460G6 & 490G6) much confusion was had surrounding the presentation of NICs to the individual Blade servers, how the host operating system would see them and what the throughput would be.

Here’s a very brief summary of how things are:
  • Each server has 2 x 10Gb LOMs (LAN on motherboard). Conceptually I find it easier to think of this as having a single switch on either side of the rack <- Something you would normally do in standard rack server implentations.
  • Each LOM is divided into 4 x NICs via a PCIe function of Flex-10. Think of it as having 2 x Quad Port NICs installed which means the operating system will see 8 x NICs. These NICs are referred to as Flex-NICs. It’s worth mentioning here that 8 x NICs are the maximum, you can have less.
  • Balance across the Flex-NICs are you would normally do taking into considering resilience by teaming the networks across both LOM1 and LOM2.
  • Flex-10 configuration permits different bandwidth presentation to each Flex-NIC, the increments for allocation are in 100m/bit.
Caveats
  • You cannot present the same VLANs across 2 different Flex-NICs on the same LOM.
  • The sum of bandwidth must not exceed 10Gb per LOM.
  • Maximum VLANs per Flex-NIC cannot (currently) exceed 28.

This may be of help when planning your next VMware implementation.

[Many thanks to Alex H for his insight and simplistic explanations]