Part 2: Consolidate Network Appliances with Virtualization

Virtualization has transformed the economics of running data centers. Indeed one could say that without virtualization, data centers would have faced a serious power consumption dilemma. With virtualization, it is now possible to make more efficient use of physical resources and thereby space and power consumption, which lead to cost savings.
Part one of this series explored how. In Part two, learn how distribute and share data between multiple clients, plus gain insight into the performance expectations and the benefits of network appliance virtualization.
Distributing data on a per physical or virtual port basis
One method of distributing data to multiple client virtual machines is by physical port:

In the example above, data on each port of the network adapter is mapped to a separate client virtual machine. However, this limits the solution by the number of physical ports on the network adapter.
A more interesting solution is to use logical ports:

Some intelligent network adapters are capable of identifying flows and thus defining logical ports providing specific flow data. These logical ports can be mapped to VMCI ports allowing specific data to be distributed to dedicated network appliances running on client virtual machines. The number of virtual ports that can be supported is limited by the implementation on the network adapter, but can be up to 32.
Sharing data between multiple virtual machine clients
As mentioned earlier, it is not uncommon for multiple network appliances to need to access the same data at the same point in the network at the same time. The captured data needs to be shared and replicated to multiple network appliances.

The data distribution virtual machine can be used to replicate the data captured by the intelligent network adapter to each virtual machine that requires that data. The only limitation is the bandwidth of the VMCI interface itself, which is dependent on the processing power of the supported CPU chipset.
Performance expectations
Implementations of the solutions thus far have been made providing a benchmark for expected performance. Napatech has successfully demonstrated that the VMCI interface can support up to 30 Gbps of data replication and distribution to multiple virtual machines. This allows any combination of port speeds and number of virtual clients to be implemented as long as the total consumed VMCI bandwidth does not exceed 30 Gbps.
Benefits of network appliance virtualization
As stated previously, not all network appliances can be virtualized, especially high-speed, high-performance appliances that require all the processing resources available. However, for less processing intensive appliance applications, there is an opportunity for consolidation that is compelling.
One of the advantages of using virtualization for consolidation is that each network appliance can be re-used to a large extent with the same operating system and environment. This also means that it is possible to upgrade the physical hardware without needing to upgrade the supported network appliance virtual machines. As physical servers continue to increase in power and performance, even more appliances can be consolidated onto a single physical server.
As network interface speeds change, it is possible to upgrade the intelligent network adapter to support a higher speed interface without having to change the support network appliance virtual machines. This possibility can also be used to upgrade existing network appliances to support higher speed interfaces in a fast and effective way.
For example, a 10 Gbps network appliance can be upgraded to support 40 Gbps by porting four instances of the network appliance software to four virtual machines running on a single server supported by a single 40 Gbps intelligent network adapter. Four logical ports are created to distribute the data between the four virtual machines making sure that none of the virtual machines receive more than the expected 10 Gbps of data. Thus, a 10 Gbps network appliance becomes a 40 Gbps network appliance without having to re-haul the network appliance application software.
This approach can also be used to upgrade older network appliances supporting legacy operating systems or where resources to update the network appliance application software no longer are available.
Virtualization enables consolidation of network appliances
Consolidation of network appliances is the last frontier of virtualization in the data center. Cost, space and power demands require that network appliances are as effectively and efficiently utilized as their application server counterparts. While many high-speed, high-performance network appliances already make optimal use of the server resources available to them, there are a number of opportunities for network appliance consolidation that can be exploited, especially as we move to higher network speeds and ever more powerful physical servers.

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