OSPF Routing Protocol Q/A's Flashcards
OSPF uses link cost and speed to calculate it’s routing metric? True / False
What does OSPF stand for?
True
Open Shortest Path First
What type of advertisement does OSPF use to pass routing updates?
(LSA) Link State Advertisements
In what order does OSPF Operate from 1 - 6?
Discover What? Form What? Flood What? Compute What? Install What? Respond to What?
- Discover Neighbors
- Form Adjacencies
- Flood Link State Database (LSDB)
- Compute Shortest Path
- Install best routes in the routing table
- Respond to network changes
What do Link State Advertisements LSA advertise?
routing updates
What are Link State Updates responsible for exchanging?
topology information
What identifies a router using OSPF?
router id
What is the cost of OSPF actually derived from?
bandwidth/interface bandwidth
What is the default cost on “All OSPF” routers?
1
When making changes to OSPF it is recommended to modify the cost not what?
bandwidth
Hello interval is the time in which, what are sent out?
hello packets
What is a dead interval?
Time in which router is declared out of service.
The router priority is used to select what types of routers for OSPF?
(DR) and (BDR)
Designated Router & Backup Designated Router
What must match for OSPF to form an adjacency?
Same two what? What two intervals? What subnet? What type of flag? What type of area flag?
Same area and network Hello and dead intervals IP subnet authentication flag stud area flag
The DR and BDR establishes a full neighbor state with all routers on the network segment. True of False
The neighbor state on other neighbors remain in what state, and do not exchange what with each other?
true
2-way state and do not exchange routes
What is the Designated Router multicast IP address for (all ospf routers)
224.0.0.5
Routers in their OSPF area maintain full or summary information about it’s own area?
Routers in other OSPF area maintain full or summary information about other areas?
Full information
Summary information
What do backbone routers maintain for each area and links in their own area?
Full Link State Databases (LSDB)
An ABR Area Border Router is used to connect to what on a OSPF network?
one or more areas to the main backbone
It is ideal to have each ABR connected to how many areas only?
two
What is area ID?
Area configured in an OSPF network
Do ABR’s automatically summarize routes?
What would happen if ABR’s routers were not summarized?
No
All routes would be flooded everywhere
An External AS in OSPF is used in an Autonomous System Boundary Routers (ASBR) to do what?
advertise external routing information throughout the AS
Do routers use the lowest or highest IP address with longest or shortest prefix to elect the router ID?
highest IP address with longest prefix
OSPF is what kind of routing protocol?
Link State
