Server Virtualization May Complicate Network Management
Server virtualization may reduce TCO but it can also complicate network management.
Server virtualization is a growing reality in data centers, but as this Computer World report claims, it may also be responsible for complicating network management. Noted in this report is the problem in assigning QoS and enforcing network policies, such as access control lists (ACLs).
"The second problem is assigning QoS and enforcing network policies, such as access control lists (ACLs). Traditionally this is done in the network switch connected to the server running the application. With server virtualization there's a software switch running under the hypervisor in the physical server -- not the traditional physical network switch that connects to the physical server.
"It is still important that policy be enforced in the the software switch. For example, if two VMs running on the server are not allowed to communicate with each other, someone who gained control of VM1 could open connections to VM2 and steal its data. If ACLs are applied by the soft switch in the server then this would be blocked."