Device, link or hardware component redundancy at strategic points in the
network leads to High Availability. HSRP provides router redundancy to network
hosts and can be optimized in several ways. VRRP and GLBP were derived from
HSRP providing additional redundancy features. Cisco uses redundant Supervisor
Engines as well as software features to optimize network resiliency upon
component failure. SRM is a Cisco High Availability solution facilitating
failover to a second MSFC. Highly available networks are those configured to
provide infrastructure paths and access to key devices at all times.