What algorithm is used by OSPF if equal cost routes exist?

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Packets are then routed along the shortest path using the shortest-path-first (SPF) algorithm. If multiple equal-cost paths exist between a source and destination address, OSPF routes packets along each path alternately, in round-robin fashion.

What is the maximum number of equal cost routes that can exist in the routing table with OSPF?

OSPF can include up to 16 equal cost routes in the routing table and perform load balancing amongst them. To configure this feature, you need to use the OSPF maximum-paths command.

Does OSPF prefer higher cost?

OSPF relies on costs that are inversely proportional to the bandwidth of the link. Therefore, higher bandwidth links are preferred to lower ones. The Cost formula is reference bandwidth divided by interface bandwidth. The default reference bandwidth of 100 Mbps is used for OSPF cost calculation.

What is the cost of OSPF?

Open Shortest Path First (OSPF) uses “Cost” as the value of metric and uses a Reference Bandwidth of 100 Mbps for cost calculation. The formula to calculate the cost is Reference Bandwidth divided by interface bandwidth. For example, in the case of 10 Mbps Ethernet , OSPF Metric Cost value is 100 Mbps / 10 Mbps = 10.

What is equal cost load balancing in OSPF?

Like other dynamic routing protocols, OSPF does equal cost load balancing, and if you have routes with equal cost paths to the same destination, then OSPF will do load sharing. Unlike Enhanced Interior Gateway Routing Protocol (EIGRP), OSPF can’t do unequal cost load balancing.

What is equal cost load balancing?

Equal-cost load balancing, as its name implies, is the balancing of a traffic load across redundant links of equal cost.

What is the default number of equal cost routes for OSPF on Cisco routers?

four equal
By default, the Cisco router supports up to four equal-cost paths to a destination for OSPF.

How does OSPF increase cost?

Two methods are available to change the OSPF cost. One method is to run the ospf cost command to directly change the interface cost, and the other is to change the bandwidth reference value to indirectly change the interface cost.

How do you prioritize OSPF routes?

Setting a Priority for OSPF Routes

Run system-view. The system view is displayed.
Run ospf [ process-id ] The OSPF process view is displayed.
Run preference [ ase ] { preference | route-policy route-policy-name } * A priority is set for OSPF routes. The parameter ase specifies a priority for AS external routes.

How does unequal cost load balancing in OSPF?

In order to enable OSPF unequal-cost load balancing, you use the bandwidth command on the interface. This command might not represent the actual speed of the link, so it can be used to manipulate how data is load-shared over different links with varying speeds.

What is equal cost route?

Equal-cost multipath (ECMP) is a network routing strategy that allows for traffic of the same session, or flow—that is, traffic with the same source and destination—to be transmitted across multiple paths of equal cost.