Module 9 Flashcards
What is the IPv4 address range reserved for multicast?
224.0.0.0 to 239.255.255.255.
What does OSPF stand for?
Open Shortest Path First.
What does the OSPF protocol do? (Routers share)
OSPF is a standard routing protocol that allows routers to share information about any new routes they have learned and their efficiency.
What is the reserved OSPF multicast address?
224.0.0.5.
What does IETF stand for?
Internet Engineering Task Force.
Which layer does OSPF work on?
The network layer.
What does SPF stand for, and what does it do?
Short Path First is an algorithm that uses the Neighbour Table, Topology Table and the Routing Table to find the shortest, most efficient path between nodes in a network backbone.
Great article about it: https://www.learncisco.net/courses/icnd-2/an-overview-of-ospf/ospf-data-overview.html
What is a neighbour table?
It’s a table that each router keeps to track the IP addresses of adjacent routers that it has a direct physical connection to. Routers that are connected indirectly (i.e. through another router) are not recorded because they’re not considered neighbours.
It’s not a table of every node on adjacent networks - just the routers.
What does the topology table do?
The topology table stores routes that have been learned from neighbour routing tables/EIGRP neighbours. It’s copied to the routing table, but it’s never used by the router to forward traffic.
The topology table doesn’t store all the routes - only the routes that have been determined by EIGRP. It also records the metrics for each of the EIGRP.
What does EIGRP stand for?
Enhanced Interior Gateway Routing Protocol.
What is EIGRP, and what does it do?
EIGRP is a network protocol that enables routers to share routing information efficiently for automating routing decisions. It was developed by Cisco Systems.
Say router 10 times fast!
What is the primary difference between OSPF and EIGRP?
The metric used to calculate the best path. EIGRP uses a metric based on internet bandwidth only, while EIGRP uses a composite metric based on different properties that are weighted, primarily bandwidth and delay.
Another key difference is EIGRP is a Cisco proprietary protocol, while OSPF is an open standard supported by multiple vendors. They are two of the most widely deployed standardised routing protocols.
But which one gets used and when? It just depends on the scenario and which protocol will work best for the application, they both have advantages and disadvantages.
What metric does OSPF use to calculate the best path?
Internet bandwidth only.
What metric does EIGRP use to calculate the best path?
A composite metric based on different properties that are weighted, primarily bandwidth and delay.
Other properties are available but aren’t always necessary to be taken into account (i.e. load, reliability, MTU, etc.)
What does IANA stand for?
Internet Assigned Numbers Authority. They manage and allocates blocks of IP addresses to the Regional Internet Registries throughout the world.
