Having completed all of the previous strategy elements, you are ready to deploy. Is that all there is to it? Not quite. In this post, I’ll highlight strategies you can use for a smooth post-deployment.
In one of my past experiences, deployment of our branch routers went off without a hitch and we patted ourselves on the back and went home. In the morning, operations noted a reload on two of the routers we had upgraded the night before. It appeared that one of the defects we evaluated had not discovered “all” of the traffic that could force the reload. So what was the impact of all this? As part of our change management strategy, we were certain to ensure that we could back out on our changes. Additionally, we set the device to load the old software and configuration if the device reloaded. This resulted in less than a minute outage for those devices that did reload and the design allowed for seamless failover between the two switches. Failure to do so would have resulted in the router continuously reloading as these packets were encountered -, which would unlikely be noticed. It is important to note that there was no impact on the production network or business services.
To implement effective change management at your company, you must initiate process and leverage tooling to automate where possible. It’s not really feasible to update 1,100 devices with a “no ip http-server” command to resolve a security advisory or deploy a new software image to 1,100 closet switches -- manually. The best planning is of little use if it cannot be implemented. Once validation has been completed, you are left with two specific areas that need to be addressed:
- Policy Management: This is where the “gold” standard configuration and software image for a class of devices is documented and compliance is tracked. When it comes to configuration, a policy could be a single value, command line, or a full configuration template. What makes a recommendation a policy is that it has been researched and validated via testing. Having a tool where the software and configuration policies can be entered and compliance tracked is critical to success. Cisco Prime LAN Management Solution provides many capabilities in this area via baseline templates that will allow you to create your own custom policies.
- Change Automation: This represents the final execution stage where you bring your network into compliance with the new or updated policy standards. There are customers with some real horror stories surrounding using tools to automate their changes. In each of these cases, the real problem was not the automation of the change but rather the validation of the change to be made. One particular instance involved a customer that read a security advisory recommending to turning off CDP to mitigate the specific vulnerability. The customer decided this was a good idea (no research or validation) and automated this change. The challenge was that this caused all of the WAN links to go down and back up (flap) instituting a rolling outage as the change job ran across the network -- during working hours! It is very tempting to “roll-the-dice” and implement a change without validating but eventually you lose and this results in outages.
Once you have executed all strategies and successfully deployed your changes to the network, you need to be able to monitor to ensure that the network is performing correctly. This is the ultimate validation of the changes and can also preemptively identify where adjustments or changes to need to be applied. It is a best practice to capture CPU, Memory and other KPI’s from a device both pre and post change to validate that the device is performing as expected post change. Every company should develop an overall network management architecture and design that captures the relevant metrics and KPI’s need to measure their business services.
In summary, to get the most ROI from your network and effectively implement change, it requires a holistic approach. I’ve outlined the strategies developed by Cisco Services including design, hardware, software, change management and network management. The Network Optimization Service (NOS) can help you implement these strategies with dedicated engineers that use these best practices and the latest smart tools to support and guide your team. To learn more, view this video or contact your account manager to see how this service can help you achieve your goals.
Now I’d like to hear from you, what’s been your experience? How do you prepare for changes to your network ?