Three different types of basic switches can be built and utilized in a Hyper-V virtual network: internal, external and private switches (Virtuatopia, 2012). An external switch at the top layer of a Hyper-V virtual network and controls access to/routes transmissions in and out of the virtual network, maintaining communication between the virtual network and the external physical network (Virtuatopia, 2012). Once inside the network, an internal switch works much like a standard virtual switch, replicating the actions and functionality of a physical switch in a traditional network and controlling/routing transmissions from terminal to terminal within the virtual network and especially between the parent partition and child partitions (Virtuatopia, 2012). A private switch creates links and controls between child partitions within the virtual network, but do not provide a route to the parent partition or the external switch and thus are more contained (Virtuatopia, 2012).
Hyper-V's switch schema offers a greater ability to partition elements in the network, with switches designed for this specific purpose (Virtuatopia, 2012). All of the switches work in similar ways, but the different controls and connections they provide are directly related to the functionality of the virtual network.
Hyper-V and Windows Server 2008
Understanding virtual networks and environments and actually putting them to use are two different things, and while in theory a great number of virtual machines could be set up on any one piece of computing hardware there is ultimately a limit in the usefulness of each of these virtual environments related to the speed and capacity of the hardware. At the same time, it is estimated that most servers typically utilize only approximately ten percent of their hardware capacity, largely as a result of the partitioning needs of many user requirements...
With Hyper-V, which is a part of the Windows Server 2008 operating system, partitioning can be achieved through the creation of multiple virtual machines or environments on a single server, each running as a virtual server fully partitioned form the others (Petri, 2009). Given the 10% figure above, it could be assumed that each server could handle ten guests, however cutting this almost half in to six will provide much greater reliability and in certain settings this number should be reduced further to allow for increased traffic from each guest (Petri, 2009).
As the setting described requires the ability to support 25 guests, there will need to be a total of five servers which would yield a total of 30 partitions -- enough to allow for some overflow or expanions. After acquiring the servers, creating the partutions and the full network is relatively straightforward. The virtual networks can be created using the existing Hyper-V application in the Windows Server 2008 OS, and external networking to user terminals completes the package.
References
Fratto, M. (2011). Virtualization. Accessed 9 October 2012. http://www.quora.com/Virtualization/How-does-virtual-environment-work
Petri, D. (2009). Implementing Hyper-V in Windows Server 2008. Accessed 9 October 2012. http://www.petri.co.il/implementing-hyper-vision-hyperv-windows-server-2008.htm
Virtuatopia. (2009). Understanding and Configuring Hyper-V Virtual Networks. Accessed 9 October 2012. http://www.virtuatopia.com/index.php/Understanding_and_Configuring_Hyper-V_Virtual_Networks
VMware. (n.d.). VMware Virtual Networking Concepts. Accessed 9 October 2012. http://www.vmware.com/files/pdf/virtual_networking_concepts.pdf
