Bug in Cisco 3650 and 3850 firmware that could affect Livewire multicast

Updated by Bryan Jones

As of the date of this writing (June - 2019), some of our customers have made us aware of an anomaly in certain Cisco firmware for their Catalyst 3850 and 3650 switches. The situation we have been informed of relates to memory usage that can lead the switch to crash, which will stop all Livewire multicast traffic.

There are very few specific details available, however, research suggests that this problem is in the Denali version of their switch software (noted as version 16.3.X) and the specific version of firmware is 16.3.6. Cisco forums and Google indicates this was introduced in 16.3.5b. There is no specific information as to what dates this particular version was shipped or what serial number ranges are affected.  

Customers who have Cisco 3650 or 3850 switches are encouraged to check their versions and update accordingly.  We have information from a number of Axia customers who have already done this and have been advised by Cisco to update to version 16.3.8 so we recommend all users consider this advice.

Please note that Telos is NOT a Cisco partner and this information is being provided “as is” in an effort to head off any possible problems. Telos strives to regularly provide information to our customers where possible problems could exist, even though they may not be our systems to begin with or one that we can directly solve.  Not being a Cisco partner means we do not have access to the versions of Cisco software. If you have a valid Cisco serial number, you should be able to create a free account and have access to the download for your switch.

Cisco Forums suggest several options:

  1. Wait for the crash
  2. Periodic reload
  3. Update the software

Please note that all of these options need to be carefully considered as they will impact your AoIP system’s ability to operate.

Customers should contact their IT group or Cisco directly for more information on this issue.  

How did we do?