Which of the following are characteristics of Open Shortest Path First (OSPF)? (Choose three.)
A.
Administrative distance of OSPF is 90
B.
Administrative distance of OSPF is 110
C.
OSPF uses the Dijkstra algorithm to calculate the SPF tree
D.
OSPF uses the Diffusing Update algorithm (DUAL) algorithm to calculate the SPF tree
E.
OSPF uses 224.0.0.5 as multicast address for ALLDRouters
F.
OSPF uses 224.0.0.6 as multicast address for ALLDRouters
Explanation:
The following are characteristics of Open Shortest Path First (OSPF) routing protocol:
The default administrative distance is 110.
It uses 224.0.0.6 as the multicast address for ALLDRouters.
It uses the Dijkstra algorithm to calculate the Shortest Path First (SPF) tree.
It uses Internet Protocol (IP) protocol 89.
OSPF supports Non-Broadcast Multi-Access (NBMA) networks such as Frame Relay, X.25, and
Asynchronous Transfer Mode (ATM). The default hello interval for NBMA networks is 30 seconds.
OSPF supports point-to-point and point-to-multipoint connections.
It also supports authentication.
OSPF uses 224.0.0.5 as the multicast address for ALLSPFRouters.
It uses link-state updates and SPF calculations that provides fast convergence.
OSPF is recommended for large networks due to good scalability.
It uses cost as the default metric.
There is no maximum hop count as with distance vector routing protocols. The number of hops to a network
can be unlimited.
The option stating that AD of OSPF is 90 is incorrect because 90 is the default administrative distance for an
internal Enhanced Interior Gateway Routing Protocol (EIGRP) route.
The option stating that OSPF uses the Diffusing Update algorithm (DUAL) algorithm to calculate the SPF tree is
incorrect. The DUAL algorithm is used by EIGRP to calculate the SPF tree.
Keep the following in mind when comparing OSPF and EIGRP:
EIGRP is vendor specific; OSPF is not
EIGRP has an AD of 90; OSPF has an AD of 110
OSPF elects a DR on each multi-access network; EIGRP does not
OSPF uses cost as its metric, and EIGRP uses bandwidth as its metric
The option stating that OSPF uses 224.0.0.5 as multicast address for ALLDRouters is incorrect because OSPF
uses 224.0.0.6 as multicast address for ALLDRouters, and 224.0.0.5 as multicast address for ALLSPFRouters.
Objective:
Routing Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot single area and multi-area OSPFv2 for IPv4 (excluding authentication,
filtering, manual summarization, redistribution, stub, virtual-link, and LSAs)Cisco > Support > IP > IP Routing > Technology Information > Technology White Paper > OSPF Design Guide
> Document ID: 7039
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Multicast Technology