In-Service Software program Upgrades eradicate downtime from wi-fi community upgrades

In collaboration with Vishal Gupta

Cisco IT has designed Wi-Fi networks with overlapping Entry Level (AP) protection and stateful, redundant Wi-fi Controllers for years. Nevertheless, our AP upgrades have at all times required system reboots outdoors of enterprise hours – creating scheduling complications for IT, and probably disruptive downtime for finish customers.

Happily, due to the In-Service Software program Upgrades (ISSU) functionality in Cisco Catalyst 9800 Collection Wi-fi Controllers, an possibility exists the place IT doesn’t need to schedule an after-hours improve, and finish customers gained’t expertise any downtime throughout work hours.

ISSU leverages Stateful Switchover (SSO) redundancy and clever AP reboots to reduce or eradicate downtime for finish customers. Protocols like 802.11v assist gracefully transition shoppers from rebooting APs to neighboring APs. When mixed with the controllers’ Radio Useful resource Monitoring (RRM) neighbor relationship intelligence, and a information of the place every consumer is related, the Catalyst 9800 is uniquely able to lowering or eliminating service interruptions throughout AP reboots.

After Cisco DNA Heart triggers and screens the ISSU workflow, right here’s the way it works:

  1. First, Cisco DNA Heart sends the golden picture to the Catalyst 9800 from its inside picture repository. The Catalyst 9800 installs it on each chassis within the SSO pair, and DNAC initiates the AP pre-download.
  2. Subsequent, Cisco DNA Heart begins ISSU on the Catalyst 9800. The Catalyst 9800 leverages SSO to improve each chassis,  periods to the APs or disrupting any shoppers.
  3. Lastly, the controller begins a “staggered” rebooting of APs in small increments. Community directors choose the share of whole APs to reboot in every iteration. The controller additionally avoids rebooting neighboring APs and makes use of 802.11v to gracefully roam shoppers. Cisco DNA Heart screens the progress and commits the software program improve when accomplished.

Buyer Zero crew assesses ISSU’s impression 

To measure ISSU’s impression on wi-fi community upgrades, the Cisco IT’s Buyer Zero crew examined and validated this characteristic by upgrading two campus wi-fi networks (comprising about 725 APs). We then validated the success of the software program improve by measuring the next metrics:

  • Shopper depend and consumer well being: AP reboots didn’t trigger any disruption to consumer well being or consumer depend. Shopper well being was inside our regular vary (higher eightieth percentile to decrease ninetieth percentile). Shopper depend was similar to days on which no software program improve was performed.
Diagram of In-Service Software Upgrades for network upgrades
ISSU timeline overlayed on consumer well being (high) and consumer depend per SSID (backside)
  • The Cisco DNA Heart machine studying (ML) engine securely learns the baseline state of a community throughout a number of parameters. We selected to give attention to onboarding time and onboarding failures. The Cisco DNA Heart ML engine didn’t register any deviations from baseline community onboarding occasions and onboarding failures. Additional, the baseline was similar to that of the 2 earlier days.
in service software upgrade machine learning
No deviations from anticipated Cisco DNA Heart machine studying baselines
  • Staggered AP reboots distribution: We regarded on the output of “present AP improve” from the Catalyst 9800 to see which APs rebooted throughout every iteration of the staggered AP reboots. We needed to make sure the distribution was balanced throughout all buildings and flooring. The Catalyst 9800’s execution of staggered reboots intently matched predictions. We selected to reboot 5% of all APs throughout every iteration and anticipated reboot counts of three APs/flooring/iteration within the first community, and two APs/flooring/iteration within the second community. Beneath are the detailed numbers for the second community:
    • Predicted: (278 APs x .05) / 7 flooring = 1.98 APs/flooring/iteration
    • Precise:86 APs/flooring/iteration

Testing validates a number of ISSU advantages

Cisco IT has dedicated to a NetDevOps method, through which we attempt for automated adjustments with predictable danger. As we method this purpose, we acquire the power to make community adjustments at any time – with out compromising our service stage to finish customers or overburdening our community engineers.  Cisco DNA Heart, Catalyst 9800, and ISSU enable us to interchange “worry of change” with newfound confidence primarily based on extra predictable outcomes.

Buyer Zero additionally performed an in depth evaluation to validate the advantages of ISSU, with the next findings:

  • Enhanced end-user expertise: We acquired no complaints or helpdesk tickets throughout this improve. Moreover, no incidents have been retroactively tied to the improve. In truth, for so long as we’ve been utilizing ISSU on the Catalyst 9800, we’ve by no means acquired a single end-user grievance.
  • Improved IT expertise: With ISSU, there is no such thing as a must schedule wi-fi infrastructure upgrades outdoors enterprise hours, or to schedule Wi-Fi community downtime.
  • Ease of improve: Cisco DNA Heart and the Catalyst 9800 work collectively to automate the ISSU course of. Community engineers can set off upgrades with just some clicks inside the Catalyst 9800’s Software program Picture Administration (SWIM) characteristic and monitor progress within the SWIM dashboard.
  • Improved safety: Simpler upgrades assist be certain that the wi-fi infrastructure is at all times present, eliminating safety vulnerabilities resulting from outdated software program.
  • Community downtime avoidance: Clever, staggered rebooting of APs reduces or eliminates Wi-Fi community downtime for finish customers.

Smoother course of. Happier engineers and finish customers. Enhanced safety. ISSU and the Catalyst 9800 mix to take the dread out of wi-fi community upgrades.

Inside Cisco IT Weblog



[1] Management and Provisioning of Wi-fi Entry Factors


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