The challenge of virtualization

Insightful analysis by consultants Steve Taylor and Jim Metzler, plus links to the latest WAN news headlines

In the last newsletter we discussed the impending perfect storm in which IT organizations implement three key initiatives, each of which are extremely beneficial, and yet end up in a place where for all practical purposes applications cease to function. In this newsletter, we will discuss primarily the first of those initiatives - virtualization. We will, however, also allude to some other closely related changes that are impacting the IT infrastructure.

At the hundred thousand foot level, there are two approaches to virtualization. In one approach, a given resource is made to look like it is multiple resources of the same type. Running multiple virtual LANs (VLAN) over the same LAN infrastructure is an example of this type of virtualization. Running multiple VPNs over a given WAN link is another. The other type of virtualization calls for combining a number of resources of the same type and having them perform as if they were one larger resource. It is a bit of a stretch, but inverse multiplexing is an example of this form of virtualization.

While we have had network virtualization for a long while, there is growing enthusiasm to virtualize a wide range of other types of IT resources, including desktops, servers and storage (Compare Storage Virtualization products). Given this trend, in the not too distant future, the information flow in the n-tier applications that are so common today will be notably different. For starters, the branch office user will be on a virtualized desktop that actually runs on servers in the data center. The user will access the branch office router over a VLAN, which may or may not be a change from the current approach. 

The branch office router, however, may well have changed. In addition to routing, the router may also host some applications or Web services. Also, since the deployment of WAN Optimization Controllers (WOC) (Compare Application Acceleration and WAN Traffic Optimization products) is increasing, in the near future it will be much more likely that the data flow transits a WOC. However, this will not be the type of WOC that we have all come to know and love. For example, in addition to providing standard WOC functions such as caching, compression and protocol acceleration, this WOC will also provide virtualized network services such as DNS and DHCP. Given the ever-increasing concern about security, in the near future it will be even more likely than it is today that there will also be a firewall in the branch office. This may be a traditional firewall, or firewall software running on a virtualized server.

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In the last newsletter we discussed the impending perfect storm in which IT organizations implement three key initiatives, each of which are extremely beneficial, and yet end up in a place where for all practical purposes applications cease to function. In this newsletter, we will discuss primarily the first of those initiatives - virtualization. We will, however, also allude to some other closely related changes that are impacting the IT infrastructure.

At the hundred thousand foot level, there are two approaches to virtualization. In one approach, a given resource is made to look like it is multiple resources of the same type. Running multiple virtual LANs (VLAN) over the same LAN infrastructure is an example of this type of virtualization. Running multiple VPNs over a given WAN link is another. The other type of virtualization calls for combining a number of resources of the same type and having them perform as if they were one larger resource. It is a bit of a stretch, but inverse multiplexing is an example of this form of virtualization.

While we have had network virtualization for a long while, there is growing enthusiasm to virtualize a wide range of other types of IT resources, including desktops, servers and storage (Compare Storage Virtualization products). Given this trend, in the not too distant future, the information flow in the n-tier applications that are so common today will be notably different. For starters, the branch office user will be on a virtualized desktop that actually runs on servers in the data center. The user will access the branch office router over a VLAN, which may or may not be a change from the current approach. 

The branch office router, however, may well have changed. In addition to routing, the router may also host some applications or Web services. Also, since the deployment of WAN Optimization Controllers (WOC) (Compare Application Acceleration and WAN Traffic Optimization products) is increasing, in the near future it will be much more likely that the data flow transits a WOC. However, this will not be the type of WOC that we have all come to know and love. For example, in addition to providing standard WOC functions such as caching, compression and protocol acceleration, this WOC will also provide virtualized network services such as DNS and DHCP. Given the ever-increasing concern about security, in the near future it will be even more likely than it is today that there will also be a firewall in the branch office. This may be a traditional firewall, or firewall software running on a virtualized server.

The data flow next transits a WAN link that today is virtually always a terrestrial link. However, for both backup and performance reasons, we will see the deployment of 3G links, which will exacerbate the WAN performance issues. Upon entering the data center, the traffic hits a virtualized application front end (AFE) which is often referred to as an application device controller (ADC). It is interesting to note that some vendors such as Cisco are taking a given AFE and turning it into a number of virtualized AFEs. Other vendors, such as A10, are combining individual AFEs into a single more powerful virtualized AFE. 

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Jim Metzler is vice president of Ashton, Metzler & Associates.