Stretch's Hierarchy of Network Needs

Remember Maslow's hierarchy of needs from school? The theory asserts that every human shares the same set of basic physical and psychological needs in order to be happy, with more primal needs like food and shelter taking precedence over emotional needs like love and companionship.

A while back, I was pondering what would be necessary to fully automate a network, and it occurred to me that a very similar hierarchy of needs can be laid out for a computer network to achieve its optimal state.

1. A Functioning Network

At the very bottom of the hierarchy is everything a network requires to function: Routers, switches, cabling, power, and so on, just as tier one of Maslow's hierarchy encompasses everything a human needs to stay alive. At this stage, a network can function, and can even function well, but it cannot adapt or grow.

Many small businesses operate their networks at this stage for years with no major problems. After all, when left alone, computers and networks tend to just keep chugging along. And if your entire network comprises a cable modem, a switch, and a few access points, it's entirely possible that it will run for years without needing any tweaking.

2. Someone to Operate the Network

Of course, more advanced networks need a human operator to make changes and address faults. At this stage, a network is associated with some human operator capable of inspecting and manipulating network components to modify the network's overall behavior. This could be a full-time network staff or just a systems administrator who pokes at a router every now and then.

At this stage, a network can grow and adapt. However, every change imposes a substantial overhead, as the human operator must first research the network's state (ascertaining the network topology, routing table, etc.) and apply all configuration changes by hand. I think it's fair to say that most networks today exist at this stage.

3. Abstraction of Network State

This is where things start to get interesting. This stage entails defining all of the network's components and how they should interoperate, in some entity separate from the network itself. As an illustration, consider running show lldp neighbors on a switch. The output will tell you what's currently connected to that switch and via which interfaces. However, it doesn't tell you what should be connected. Similarly, just reviewing the running configuration on a router doesn't tell you whether that configuration is correct, only that it exists.

But, if we employ IP address and infrastructure management systems and configuration templating, we can form some assertions indicating how the network should function. This model becomes the "source of truth" for the network: If some attribute doesn't exist in the model, it shouldn't exist in the real world. We can compare the real-word state of the network to the source of truth to identify and resolve any discrepancies.

4. Automated Provisioning

At this stage, we abandon manual configuration changes in favor of deployments driven through automation. For example, instead of loading a configuration into a new switch by hand, we simply hook the switch up to the network and it downloads the appropriate configuration — generated according to our source of truth established in stage three — through an automated provisioning service. Humans no longer need to be involved in the process.

Extending this idea further, we can develop systems to automatically apply configuration changes to keep the network synchronized with its abstracted state. If we want to add a link between two nodes, we simply update the model through some human-friendly UI, and the system automatically configures the relevant interface on either node in anticipation of the new link.

5. Automated Remediation

This is really the holy grail of our field: networks that fix themselves. And I don't mean routing traffic via an alternate path when a link goes down. I mean things like:

• External monitoring alerts for sub-SLA performance of traffic via a certain Internet provider. Edge routers are automatically reconfigured to de-preference links for that provider to restore performance to acceptable levels.

• A router detects that one of its line cards is experiencing hardware failures. The line card is taken offline and a TAC case (complete with logs and inventory data) is raised automatically with the vendor to initiate an RMA.

• A rack loses one of its two redundant access switches. The network detects the hazardous condition and begins migrating virtual machines to racks that have full connectivity.

Networks that reach this stage are truly awesome. And here's the best part: All of these things are easily in reach with modern technology. We just need to build it.