What is OSPF metric type?
OSPF supports two types of external metrics: Type 1 and Type 2. The difference between the two metrics is how OSPF calculates the cost of the route. Type 1 external metrics are equivalent to the link-state metric, where the cost is equal to the sum of the internal costs plus the external cost.
Which formula is used for calculating OSPF interface costs?
OSPF uses the following formula to calculate the path cost when interface bandwidth is available: OSPF path cost = ((auto-cost × reference-bandwidth + interface bandwidth) -1) / interface bandwidth.
IS IS routing protocol metric?
The Routing Information Protocol (RIP) always uses hop count as the metric. A hop means going through another router. Hop count is the number of routers the router has to go through to get to the destination network.
What is OSPF metric type1?
A type 1 route has a metric that is the sum of the internal OSPF cost and the external redistributed cost. If routes are redistributed into OSPF as type 1, then the cost to reach the external networks could vary from router to router.
What is a NSSA area?
NSSA (Not so stubby area) is an OSPF area type that allows the injection of external routes into the stub area by using a special LSA type called LSA type 7. This LSA type 7 is converted into an LSA type 5 when it leaves the NSSA area.
What is OSPF LSA?
The link-state advertisement (LSA) is a basic communication means of the OSPF routing protocol for the Internet Protocol (IP). It communicates the router’s local routing topology to all other local routers in the same OSPF area.
What is stub area in OSPF?
Stub areas are areas through which or into which OSPF does not flood AS external link-state advertisements (Type 5 LSAs).
Is metric A calculation?
Unlike OSPF, in which the link metric is calculated automatically based on bandwidth, there is no automatic calculation for IS-IS. All IS-IS links use a metric of 10 by default. Normally, IS-IS metrics can have values up to 63.
What is topology table in OSPF?
The OSPF process builds and maintains three separate tables: • A neighbor table – contains a list of all neighboring routers. • A topology table – contains a list of all possible routes to all known networks within an area. • A routing table – contains the best route for each known network.
What does OSPF use as metric?
A. OSPF uses the metric aCost, which is related to the bandwidth. If there are equal cost paths (the same bandwidth on both multilinks), OSPF installs both routes in the routing table. The routing table tries to use both links equally, regardless of the interface utilization.
What is the meaning of “routing bit set” in OSPF?
well, Routing Bit Set in ospf database means route is installed in RIB. not all routes existing in databse will have Routing Bit Set. i.e. 2 summary routes listed in database but router picks 1 as best one (lower cost) and puts into RIB.
How does OSPF protocol work?
OSPF as a link-state protocol. The router processes all data in the topology table and makes use of the Dijkstra algorithm to determine all routes to all networks, as well as the least-cost routes. All this information is stored in the SFP tree, identifying preferred and secondary routes.