On the network shown in the figure, if all links are Ethernet links and all routers run OSPF, how many DRs will be elected on the entire network?
On the network shown in the figure, if all links are Ethernet links and all routers run OSPF, how many DRs will be elected on the entire network?
In an OSPF network, a Designated Router (DR) is elected in every broadcast and non-broadcast multi-access network. In the given network, there are four Ethernet links, each connecting two routers. Each Ethernet link is a separate broadcast domain, so a DR will be elected for each of these four links. However, the figure shows pairs of routers connected via point-to-point Ethernet links and not multi-access segments. As a result, there will be one DR for each multi-access segment. Analyzing the network, we can see only three multi-access networks: 10.0.12.0/24, 10.0.24.0/24, and 10.0.34.0/24. Therefore, the total number of DRs elected on the entire network will be 3.
Correct answer B: A multi-access segment can have only one DR and no more than one BDR. Depending on how many multi-access segments may be in an OSPF area, the area can have many DRs and many BDRs.