The management imperative: Change

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

The last newsletter discussed some of the factors related to server virtualization that are causing networks to undergo fundamental change. This newsletter will discuss some related factors that are also causing IT organizations to fundamentally rethink their approach to network management. This newsletter will also encourage readers to attend the forthcoming Interop session that Jim is moderating that is entitled "Why Networking Must Fundamentally Change." This session will be referred to in this newsletter as The Session.

One of the many benefits of server virtualization is that it is now possible to move virtual machines between servers either in the same or in disparate data centers. However, this creates some significant management challenges. For example traffic routing to and from a virtual machine may need to be modified so that any traffic flows in an optimized way to the virtual machine's new location once it has been moved. If the user traffic to the virtual machine originates in the same Layer 2 domain, then a Layer 2 extension may well suffice. The networking vendors who participate on The Session will discuss the role of a Layer 2 extension.

However, if the user traffic to the virtual machine is traversing a Layer 3 network or the Internet, then granular routes need to be advertised by the destination data center for migrated virtual machines. If these changes are not provisioned, sub-optimal routing may result in additional delay, which may not be acceptable for some applications. To help ensure that the traffic from the virtual machine is optimally routed, the IP addresses of the default gateways of the data subnets in both the primary and secondary data centers need to be identical. Where remote clients are accessing VM-resident applications front ended by a load balancing device, the DNS lookup of the application server has to return the virtual IP address of the load balancer where the VM currently resides. These two factors require that the configurations of the DHCP server, DNS server, load balancer and virtual server management systems be kept in synchronization. While all of this is doable, it is not easy and it really can not be done with manual, narrowly-focused network management tools.

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The last newsletter discussed some of the factors related to server virtualization that are causing networks to undergo fundamental change. This newsletter will discuss some related factors that are also causing IT organizations to fundamentally rethink their approach to network management. This newsletter will also encourage readers to attend the forthcoming Interop session that Jim is moderating that is entitled "Why Networking Must Fundamentally Change." This session will be referred to in this newsletter as The Session.

One of the many benefits of server virtualization is that it is now possible to move virtual machines between servers either in the same or in disparate data centers. However, this creates some significant management challenges. For example traffic routing to and from a virtual machine may need to be modified so that any traffic flows in an optimized way to the virtual machine's new location once it has been moved. If the user traffic to the virtual machine originates in the same Layer 2 domain, then a Layer 2 extension may well suffice. The networking vendors who participate on The Session will discuss the role of a Layer 2 extension.

However, if the user traffic to the virtual machine is traversing a Layer 3 network or the Internet, then granular routes need to be advertised by the destination data center for migrated virtual machines. If these changes are not provisioned, sub-optimal routing may result in additional delay, which may not be acceptable for some applications. To help ensure that the traffic from the virtual machine is optimally routed, the IP addresses of the default gateways of the data subnets in both the primary and secondary data centers need to be identical. Where remote clients are accessing VM-resident applications front ended by a load balancing device, the DNS lookup of the application server has to return the virtual IP address of the load balancer where the VM currently resides. These two factors require that the configurations of the DHCP server, DNS server, load balancer and virtual server management systems be kept in synchronization. While all of this is doable, it is not easy and it really can not be done with manual, narrowly-focused network management tools.

On Tuesday, April 27 from 2:45 to 5 p.m. Jim is moderating a deep-dive panel at Interop entitled "Why Networking Must Fundamentally Change." There will be two groups of vendors on the panel. One is network centric and the other is network management centric. The management centric panelists come from LineSider, InfoBlox and Egenera. The session will begin with these panelists identifying the factors that are driving network management to fundamentally change and their suggested changes. There will be lots of time for questions from the audience. If you will be at Interop, you really should attend this session.

Read more about lans & wans in Network World's LANs & WANs section.

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