Layer 3 Strategies
There are several Layer 3 availability design options. Layer 3 availability designs are desirable because there could be a fault at the IP layer, but not at the lower layers. By implementing a Layer 3 availability strategy, we can infer the status of the network at all layers below, but not at the layers above. The fault detection and recovery can be relatively slower than Layer 2 strategies, depending on the strategy.
In this section we explain the operation and recovery times for three approaches:
VRRP and IPMP – proven to be very useful at the server-to-default router network connectivity segment of the data center network
OSPF – a proven and effective link-state routing protocol, suitable for inter-switch connectivity ...