Technical Articles
F5 SMEs share good practice.
Showing results for 
Search instead for 
Did you mean: 
Custom Alert Banner
F5 Employee
F5 Employee

Greg Ness calls it "connectivity intelligence" but it seems that we're really talking about is the ability of network infrastructure to both be agile itself and enable IT agility at the same time. Brittle, inflexible infrastructures - whether they are implemented in hardware or software or both - are not agile enough to deal with an evolving, dynamic application architecture.

Greg says in a previous post

The static infrastructure was not architected to keep up with these new levels of change and complexity without a new layer of connectivity intelligence, delivering dynamic information between endpoint instances and everything from Ethernet switches and firewalls to application front ends. Empowered with dynamic feedback, the existing deployed infrastructure can evolve into an even more responsive, resilient and flexible network and deliver new economies of scale.

The issue I see is this: it's all too network focused. Knowing that a virtual machine instance came online and needs an IP address, security policies, and to be added to a VLAN on the switch is very network-centric. Necessary, but network-centric. The VM came online for a reason, and that reason is most likely an application specific one. Greg has referred several times to the Trusted Computing Group's IF-MAP specification, which provides the basics through which connectivity intelligence could certainly be implemented if vendors could all agree to implement it. The problem with IF-MAP and, indeed, most specifications that come out of a group of network-focused organizers is that they are, well, network-focused. In fact, reading through IF-MAP I found many similarities between its operations (functions) and those found in the more application-focused security standard, SAML.

While IF-MAP allows for custom data to be included, which could be used by application vendors to IF-MAP enable application servers through which more application specific details could be included in the dynamic infrastructure feedback loop, that's not as agile as it could be because it doesn't allow for a simple, standard mechanism through which application developers can integrate application specific details into that feedback loop. And yet that's exactly what we need to complete this dynamic feedback loop and create a truly flexible, agile infrastructure because the applications are endpoints; they, too, need to be managed and secured and integrated into the Infrastructure 2.0 world.

While I agree with Greg that IP address management in general and managing a constantly changing heterogeneous infrastructure is a nightmare that standards like IF-MAP might certainly help IT wake up from, there's another level of managing the dynamic environments associated with cloud computing and virtualization that generally isn't addressed by very network-specific standards like IF-MAP: the application layer.

In order for a specification like IF-MAP to address the application layer, application developers would need to integrate (become an IF-MAP client) the code necessary to act as part of an IF-MAP enabled infrastructure. That's because knowing that a virtual machine just came online is one thing; understanding which application it is, what application policies need to be applied, and what application-specific processing might be necessary in the rest of the infrastructure is another. It's all contextual, and based on variables we can't know ahead of time. This can't be determined before the application is actually written, so it can't be something written by vendors and shipped as a "value add". Application security and switching policies are peculiar to the application; they're unique and the only way we, as vendors, can provide that integration without foreknowledge of that uniqueness is to abstract applications to a general use case. That completely destroys the concept of agility because it doesn't take into consideration the application environment as it is at any given moment in time. It results in static, brittle integration that is essentially no more useful than SNMP would be if it were integrated into an application.

We can all sit around and integrate with VMWare, and Hyper-V, and Xen. We can learn to speak IF-MAP or (some other common standard) and integrate with DNS and DHCP servers, with network security devices and with layer 2-3 switches. But we are still going to have to manually manage the applications that are ultimately the reason for the existence of such virtualized environments. While we are getting our infrastructure up to speed so that it is easier and less costly to manage is necessary, let's not forget about the applications we also still have to manage.   0151T000003d8HgQAI.jpg

Dynamic feedback is great and we have, today, the ability to enable pieces of that dynamic feedback loop. Customers can, today, use tools like iControl and iRules to build a feedback loop between their application delivery network and applications, regardless of whether those applications are in a VM or a Java EE container, or on a Microsoft server. But this feedback is specific to one vendor, and doesn't necessarily include the rest of the infrastructure. Greg is talking about general dynamic feedback at the network layer. He's specifically (and understandably) concerned with network agility, not application agility. That's why he calls it infrastructure 2.0 and not application something 2.0.

Greg points as an example to the constant levels of change introduced by virtual machines coming on and off line and the difficulties inherent in trying to manage that change via static, infrastructure 1.0 products. That's all completely true and needs to be addressed by infrastructure vendors. But we also need to consider how to enable agility at the application layer, so the feedback loop that drives security and routing and switching and acceleration and delivery configurations in real-time can adapt to conditions within and around the applications we are trying to manage in the first place.

It's all about the application in the end. Endpoints - whether internal or external to the data center - are requesting access and IP addresses for one reason: to get a resource served by an application. That application may be TCP-based, it may be HTTP-based, it may be riding on UDP. Regardless of the network-layer transport mechanisms, it's still an application - a browser, a server-side web application, a SOA service - and its unique needs must be considered in order for the feedback loop to be complete. How else will you know which application just came online or went offline? How do you know what security to apply if you don't know what you might be trying to secure?

Somehow the network-centric standards that might evolve from a push to a more agile infrastructure must broaden their focus and consider how an application might integrate with such standards or what information they might provide as part of this dynamic feedback loop that will drive a more agile infrastructure. Any such standard emerging upon which Infrastructure 2.0 is built must somehow be accessible and developer-friendly and take into consideration application-specific resources as well as network-resources, and provide a standard means by which information about the application that can drive the infrastructure to adapt to its unique needs can be shared.  

If it doesn't, we're going to end up with the same fractured "us versus them" siloed infrastructure we've had for years. That's no longer reasonable. The network and the application are inexorably linked now, thanks to cloud computing and the Internet in general. Managing thousands of instances of an application will be as painful as managing thousands of IP addresses. As Greg points out, that doesn't work very well right now and it's costing us a lot of money and time and effort to do so. We know where this ends up, because we've seen it happen already. The same diseconomies of scale that affect TCP/IP are going to affect application management. We should be more proactive in addressing the same management issues that will arise with trying to manage thousands of applications and services rather than waiting until it, too, can no longer be ignored.

0151T000003d4HeQAI.png 0151T000003d4HfQAI.gif0151T000003d4HmQAI.png0151T000003d4HvQAI.gif 0151T000003d4HwQAI.png 0151T000003d4IgQAI.png AddThis Feed Button Bookmark and Share

F5 Employee
F5 Employee
How VM sprawl will drive the urgency of the network evolution
Version history
Last update:
‎29-Oct-2008 04:08
Updated by: