LTE subscription plans tend to provide for an amount of monthly traffic that can be sent and received as part of the monthly rate plan. When that amount of traffic is exceeded within a monthly period, overage charges may be applied, or those bytes may be subtracted from a pool of bytes allowed for an organization with multiple subscriptions.
An organization may wish to track and be advised when an LTE attached device approaches the byte count provided with that device’s monthly subscription. This may be simply for informational purposes, or to allow for a change to the routing policy. This could include using an alternate last mile access for communications for the remainder of the period.
This “Byte Count Monitor” EEM sample solution provides a way to track monthly usage of 4G LTE interfaces on an ISR. The script logs (to syslog and console) the amount of traffic sent and received on an LTE interface at the end of each monthly period. Also, if the amount of traffic within the monthly period exceeds a configurable threshold (percentage) of the monthly usage plan, a (syslog/console) message is logged on the ISR.
The app has been enhanced to optionally reroute traffic from the cellular interface (by automatically “shutting” the cell interface) if the monthly data usage plan has been exceeded. This option would be available if there is an alternate WAN interface. On the date of the month that the subscription’s byte count refreshes, the interface would be re-enabled automatically by the app. If this option is not enabled, the app will operate as described above.
If the app is enabled along with the "commandoversms" app (allows out-of-band ISR management via text message available here: https://supportforums.cisco.com/document/12316801/commands-over-sms), texting the word "usage" to the ISR returns the current number of bytes used during the current monthly subscription period and the percentage of the byte plan used.
The attached zip file includes the TCL file and a word document that explains the details of the logic used to monitor the amount of traffic over a 4G interface and present alarms when the byte count percentage goes over a given threshold.