Zocalo coffee shop migrated to digital registers with a solution from square. While these devices are able to process transactions off-line, some types of transactions need the square registers to be on-line. At the time the coffee shop had only one up-link provided by Comcast. Comcast was providing good service at the time, but with the increased demand for the registers to be on-line they needed higher availability. Attempts at getting better service from Comcast were pursued; all of the supported routers were tried, technicians came out and audited the wiring, but we still saw a few < 10 minute outages throughout the day. According to Comcast these were not counted as outages because the lasted less then 10 minutes which is the threshold. A goal of less then 7 downtime per outage was set. To accomplish this a custom solution was crafted leveraging the existing Nagios infrastructure, a custom Perl daemon, a FTDI UMR245R, and a power tail. As soon as an external target server becomes unreachable for greater then a configured threshold then the default gateway is switched from the Comcast link to the ATT link, and the power-tail power-cycles the Comcast modem (triggered from an event service handler which calls a custom c binary that communicates with the FTDI UMR245R via calls to libftdi). Once the Comcast link is detected to be up for longer then the configured threshold the default gateway is switched back to the Comcast link.

Start: 
2016