Distributed network monitoring with IP SLA!
The Cisco IP Service Level Agreement (IP SLA) technology is nothing new to network engineers. In its basic operations, IP SLA enables routers and switches to use a protocol like ICMP to check end-to-end response time between the device itself and a destination IP device.
As stated in the Cisco IP SLA configuration guide, “IP SLAs uses active traffic monitoring—the generation of traffic in a continuous, reliable, and predictable manner—for measuring network performance”.
One of the most common uses of IP SLA is configuring floating static routes to determine the preferred active link or, in HSRP, to assure that the router with the highest priority to take over that gateway function has access to the default route.