What are two drawbacks of implementing a link-state routing protocol? (Choose two.)
A.
the sequencing and acknowledgment of link-state packets
B.
the requirement for a hierarchical IP addressing scheme for optimal functionality
C.
the high volume of link-state advertisements in a converged network
D.
the high demand on router resources to run the link-state routing algorithm
E.
the large size of the topology table listing all advertised routes in the converged network
Explanation:
Link State routing protocols, such as OSPF and IS-IS, converge more quickly than
their distance vector routing protocols such as RIPv1, RIPv2, EIGRP and so on, throught the use
of flooding and triggered updates. In link state protocols, changes are flooded immediatedly and
computed in parallel. Triggered updates improve convergence time by requiring routers to send an
update message immediately upon learning of a route change. These updates are triggered by
some event, such as a new link becoming available oor an existing link failing. The main
drawbacks to link state routing protocols are the amount of CPU overhead involved in calculating
route changes and memory resources that are required to store neighbor tables, route tables and
a complete topology table.
http://www.ciscopress.com/articles/article.asp?p=24090&seqNum=4
Answers are D and E. You say it to the explanation too..
Im confused, so B is not an answer? I dont know if its a drawback, but its defeintly true.
I think B and D are correct. Why?
A: Not relevant.
B: This is a big SHOULD when implementing LS routing protocols.
C: When the network is in a “converged” state, it means that is stable and no advertisements are being sent.
D: Big drawback while running DUAL or SPF algorithms.
E: It’s a real situation, but I think the problem is not the size of the table as much as the demand on the router’s resources caused by the LS algorithms.
I might be wrong, but IMHO B and D is the correct answer here.
I do not think OSPF has a topology table…
ChickenAdobo is correct. OSPF does not store a Topology Table.
For the record, OSPF does have a topology table. It is known as the Link State Database. It would have to have a topology table of some sort in order to converge as fast as it does. Having said that, I still think the correct answers are D and E.