Thursday, October 6, 2016

Big Data Analytics for Your Network

The help desk just called. Users are reporting the wireless is down in your office, and nobody can get on the network. The wireless seems fine to you. You're connected. You ask a few people nearby, and they're connected too. You log into the WLC and don't see any problems. works fine. Maybe you should just turn the controller off and then back on again. That worked last time. No, that's a bad idea. It's the middle of the day and you actually need to troubleshoot it.

After a bit of troubleshooting, you determine the cause of the issue is not the wireless. The DHCP scope is exhausted. Users could connect, but they couldn't obtain an IP address. You shorten the lease time, expand the scope, and call it a day. While you're at it, you wonder if DHCP is the reason connecting has been taking longer than usual, so you fire up Wireshark.

Discover, offer, request, acknowledge. You remember that from a CCNA class half a lifetime ago. Looks good. Well, you think it looks good. It takes about 227 milliseconds from discover to offer. That's normal, right? You realize you're not sure what normal is. You don't know your baseline, and you have no idea how long DHCP should take from discover to offer or request to acknowledge. What about dot1x? Is the RADIUS server slowing things down? You really have no idea. It works. It's lunch time. Nobody is complaining - right now.

Ok, hopefully the way you run your network is nothing like this. However, let's face it: this is an exaggerated version of the reality that many deal with on a day to day basis. There is often little insight into the individual operations that contribute to network performance as a whole. "The wireless is down" could mean any number of things, many of which may be out of the purview of the team managing the wireless network. Troubleshooting is often a reactive process. Even when there is visibility into network operations and baselines are known, it can be difficult to determine if your "normal" is actually optimal.

I recently attended a presentation by Nyansa at Networking Field Day 12. Nyansa is a startup focusing on what they call Cloudsourced Network Analytics. Their goal is to go beyond providing visibility in the form of pretty graphs and actually provide actionable insight about how to improve the end user experience.