BGP Dampening

BGP route dampening can be used to reduce the propagation of unstable routes throughout a network. When a prefix flaps it will be assigned a penalty of 1000 and moved into the dampening state “history”. Each flap incurs another penalty (of 1000), which is applied cumulatively. If the penalty reaches the suppress-limit, the route is dampened, meaning it won’t be advertised to any neighbors. The default values for each dampening criteria are stated below:

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Active-active router redundancy using VARP

In most of Leaf-Spine deployments, redundancy in Spine layer is required to achieve high availability and to prevent network service disruption. Modern layer 2 networks adopted loop-free and balanced path networks using Multi Chassis Link Aggregation topologies with LACP port channels, leaving loop control methods (STP) as second protection layer. Spines also supports layer 3 networks, using ECMP in a scalable network topology. For unicast redundancy in layer 3, a common method is use First Hop Router Redundancy (FHRR) to provide a simple and unique gateway for Leaf level. VRRP and HRSP are popular FHRR protocols and supported in most equipments today. Although HSRP and VRRP provide redundancy, they are active-standby FHRR protocols and do not provide a balanced data traffic distribution over Multi Chassis Link Aggregated topologies. The following figure show show data traffic is handled using active-standby FHRR protocol topology.

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