XOS Network Virtualization (XNV) is Extreme's foray into supporting virtualization in the data center. XNV, the company claims, provides visibility, control and automation to a virtual infrastructure by tracking virtual machines and applying port policies as VMs move from hypervisor to hypervisor. Not only do port policies ensure that virtual machines are properly supported on the network, but they can also be used to stop virtual server sprawl by restricting unauthorized VMs from coming on-line.
Port policies define the characteristics that are applied to switch ports. In a data center where there is a 1:1 relationship of a server to a port, administrators can apply QoS and access controls at the access port that grooms ingress traffic from the server. Data centers relying on physical servers are largely static and don't move. In a virtualized data center, not only can there be multiple servers on a physical port, but each virtual server can move from physical server to physical server. The servers' port profiles should move with them. Virtual port profiles apply QoS and access controls to virtual servers and should move with the server.
When a new VM is provisioned and assigned a port profile, XNV performs the server identification and assigning port profiles automatically. XNV was designed to be automated. Working with Extreme's Epicenter management system, the switches will detect VM moves and will apply the port profile wherever it lands, even if that is on a different switch. Many vendors have virtual port profile capabilities, so this is a must have feature. XNV works with both VMware's vCenter and Microsoft Hyper-V.
Many infrastructure vendors profess a move to flatten the physical network and remove multiple switch tiers. For example, data center switching often uses a top of rack switch to connect servers to the network, then top of rack switches connect to end or row switches or directly to core switches. The number of tiers largely depends on the amount of physical aggregation required to get hosts onto the network. Direct Attach is Extreme's attempt to remove one or more tiers, reducing capital and operational costs with additional tiers and improving network performance by reducing hop-by-hop latency.