Neterion, Inc. announced today a new set of high-capacity network interface cards designed to let customers set bandwidth and performance guarantees for specific applications running on specific virtual machines within one physical server. The capability, whichNeterion calls I\/O Quality of Service, is built into a new generation of network interface cards (NIC) designed specifically for servers hosting many virtual machines. Network interfaces can become a bottleneck for VM hosts as many virtual servers jockey for a limited amount of bandwidth, according to Chris Wolf, analyst at the Burton Group. One solution is to add not just one, but sometimes three, four or five NICs to the same machine and let the increase in raw bandwidth open the bottleneck, according to Ravi Chalaka, VP of marketing at Neterion.That makes each host far more complex and difficult to manage than a server with just one NIC, however, not to mention the additional cabling, heat and power requirements, he said. A number of other companies are also addressing theI\/O congestion problemin virtual machines.Neterion's solution, originally announced in February is to configure a server with just one 10 Gbit\/sec interface card that has quality of service functions built in. The NICs, which are priced between $1,000 and $2000 apiece, depending on configuration, are designed to give customers the ability to guarantee bandwidth to specific applications or virtual machines. That has the dual effect of limiting the number of cables and NICs in the data center, and allowing customers to virtualize applications such as transaction servers that have had too high an I\/O requirement to run on virtual servers before, he said. The problem is real and the approach makes a certain amount of sense, Wolf says. But building I\/O quality of service functionality only into the NIC will have a tendency to lock the customer in to network interface cards from just one vendor. Adding a device driver to the VM to enable it to take advantage of another layer of intelligence to the network interface which already has to pass from applications and guest operating systems and hypervisors and the host operating system can increase the complexity of a single server's interface.On the other hand, Wolf says, specialized security appliances, which are virtually stapled to a virtual machine and are given responsibility for firewalling, intrusion detection and other functions, could benefit from guaranteed bandwidth."If you're trying to funnel traffic through a security appliance that's doing some heavy packet inspection, that could really benefit from the increase in bandwidth," Wolf says. Neterion will demonstrate the technology at next week's VMworld in Las Vegas.