Question 10 - Routers and Routing Flashcards
EIGRP and OSPF are both routing protocols. List the characteristics that define each.
Characteristics of OSPF:
● It supports classless interdomain routing (CIDR).
● It is a link-state routing protocol.
● The shortest path first algorithm is used to find the lowest cost path.
● Routing updates are flooded as topology changes occur.
Characteristics of EIGRP:
● It is a Cisco proprietary protocol.
● It uses enhanced distance-vector routing that includes elements of distance-vector and link state.
● It uses diffusing update algorithm (DUAL) to calculate the shortest path.
● Routing updates are multicast using 224.0.0.10 triggered by topology changes.
● It uses unequal cost load balancing.
Explain the essential features that enable a router to learn about other networks and then forward packets towards their destination.
Routing is the process that a router uses to forward packets toward the destination network. Routing decisions are made by comparing destination IP addresses with a routing table and forwarding the packet on the designated interface. To make the correct decisions, routers must learn how to reach remote networks by sharing information with other routers. Routing protocols (such as EIGRP) are used to learn about other networks. Routes can be determined dynamically or statically.
Explain what you understand by the term ‘discontiguous network’. Why is RIP v1 unable to handle these networks correctly?
A discontiguous network is one in which a classful major address is separated by one or more other major networks. Routing protocols such as RIP, which do not include subnet information in their routing updates, summarise routes upon the basis of classful address boundaries. As a consequence the router will ‘see’ two networks with the same classful address and it will not route packets consistently to the correct sub-networks.
