D-Link DFL-260 Product Manual - Page 166

4.4. Route Load Balancing Chapter 4. Routing done according to which algorithm is selected in the table's RLB Instance object: • Round Robin Successive routes are chosen from the matching routes in a "round robin" fashion provided that the metric of the routes is the same. This results in route lookups being spread evenly across matching routes with same metric. If the matching routes have unequal metrics then routes with lower metrics are selected more often and in proportion to the relative values of all metrics (this is explained further below). Figure 4.5. The RLB Round Robin Algorithm • Destination This is similar to Round Robin but provides "stickiness" so that unique destination IP addresses always get the same route from a lookup. The importance of this is that it means that a particular destination application can see all traffic coming from the same source IP address. • Spillover Spillover is not similar to the previous algorithms. With spillover, the first matching route's interface is repeatedly used until the Spillover Limits of that route's interface are continuously exceeded for the Hold Timer number of seconds. Once this happens, the next matching route is then chosen. The Spillover Limits for an interface are set in the RLB Algorithm Settings along with the Hold Timer number of seconds (the default is 30 seconds) for the interface. When the traffic passing through the original route's interface falls below the Spillover Limits continuously for the Hold Timer number of seconds, route lookups will then revert back to the original route and its associated interface. 166