4 Replies Latest reply on Jan 27, 2009 9:40 PM by pravin2650

    pcnet32,vmxnet information

    pravin2650 Novice





      Can anyone please point out to documentation or information material on pcnet32, vmxnet?



      I am intrested in knowing how these modules help guest machine to communicate with actual NIC card etc.



      So information on how these modules are really handled by VMWare etc .. will be of really help to me..






      Thanks in Advance..!






        • 1. Re: pcnet32,vmxnet information
          AWo Guru



          Available Network Adapters


          The following network adapters might be available for your virtual machine, depending on the factors discussed above:



          • Vlance — Vlance (also called PCNet32) is a faithful virtual implementation of a common, if now somewhat aging, physical network adapter. Most 32-bit guest operating systems, except for Windows Vista, have built-in support for this card so a virtual machine configured with this network adapter can use its network immediately.


          • vmxnet — The vmxnet virtual network adapter has no physical counterpart. VMware makes vmxnet available because Vlance, a faithful implementation of a physical card, is far from optimal for network performance in a virtual machine. Vmxnet is highly optimized for performance in a virtual machine. Because there is no physical card of type vmxnet, operating system vendors do not provide built-in drivers for this card. You must install VMware Tools to have a driver for the vmxnet network adapter available.


          • Flexible — The Flexible network adapter identifies itself as a Vlance adapter when a virtual machine boots, but initializes itself and functions as either a Vlance or a vmxnet adapter, depending which driver initializes it. VMware Tools versions recent enough to know about the Flexible network adapter include the vmxnet driver but identify it as an updated Vlance driver, so the guest operating system uses that driver. When using the Flexible network adapter, you can have vmxnet performance when sufficiently recent VMware tools are installed. When an older version of VMware Tools is installed, the Flexible adapter uses the Vlance adapter (with Vlance performance) rather than giving no network capability at all when it can’t find the vmxnet adapter.


          • e1000 — e1000 is a faithful virtual implementation of a physical network adapter that is broadly supported by newer operating systems, specifically most 64-bit operating systems and both 32- and 64-bit Windows Vista. e1000 performance is intermediate between Vlance and vmxnet.


          • Enhanced vmxnet — The enhanced vmxnet adapter is based on the vmxnet adapter but provides some high-performance features commonly used on modern networks, such as jumbo frames. This virtual network adapter is the current state-of-the-art device in virtual network adapter performance, but it is available only for some guest operating systems on ESX Server 3.5. This network adapter will become available for additional guest operating systems in the future.


                Enhanced VMXNET is supported only for a limited set of guest operating systems:

                    o 32/64-bit versions of Microsoft Windows 2003 (Enterprise and Datacenter Editions). You can use enhanced vmxnet adapters with other versions of the Microsoft Windows 2003 operating system, but a workaround is required to enable the option in the VI Client. See http://kb.vmware.com/kb/1007195.

                    o 32/64-bit versions Red Hat Enterprise Linux 5.0

                    o 32/64-bit versions SUSE Linux Enterprise Server 10

                    o 64-bit versions Red Hat Enterprise Linux 4.0


          If you found this information useful, please consider awarding points for "Correct" or "Helpful" answers/replies. Thanks!!

          • 2. Re: pcnet32,vmxnet information
            vmroyale Guru
            vExpertUser Moderators



            These two docs should help:


            Networking Performance

            Performance Comparison of Virtual Network Devices


            Good Luck!

            1 person found this helpful
            • 3. Re: pcnet32,vmxnet information
              pravin2650 Novice

              Thanks for the information.. 

              • 4. Re: pcnet32,vmxnet information
                pravin2650 Novice

                Thanks !