Module 1 Flashcards
What does OSPF mean
Open Shortest Path First
A link-state routing protocol that was developed as an alternative for the distance vector Routing Information Protocol (RIP)
OSPF
an interface on a router, a network segment that connects two routers, or a stub network such as an Ethernet LAN that is connected to a single router
link
What are the five types of OSPF Packets?
- Hello packet
- Database description packet
- Link-state request packet
- Link-state update packet
- Link-state acknowledgment packet
OSPF database which lists of all neighbor routers to which a router has established bi-directional communication
Adjacency Database
OSPF database which lists information about all other routers in the network.
Link-state Database (LSDB)
OSPF database which lists the routes generated when an algorithm is run on the link-state database
Forwarding Database
5 link-state routing steps that are completed by a router
- Establish Neighbor Adjacencies
- Exchange Link-State Advertisements
- Build the Link State Database
- Execute the SPF Algorithm
- Choose the Best Route
OSPF implementation where all routers are in one area
Single-Area OSPF
OSPF implementation where OSPF is implemented using multiple areas, in a hierarchical fashion. All areas must connect to the backbone area (area 0)
Multiarea OSPF
Routers interconnecting the areas are referred to as ____
Area Border Routers (ABRs)
OSPF packet which discovers neighbors and builds adjacencies between them
Hello Packet
OSPF packet which checks for database synchronization between routers
Database Description (DBD)
OSPF packet which requests specific link-state records from router to router
Link-State Request (LSR)
OSPF packet which sends specifically requested link-state records
Link-State Update (LSU)
OSPF packet which acknowledges the other packet types
Link-State Acknowledgment (LSAck)
What are the 7 states of OSPF operation?
- Down state
- Init state
- Two-way state
- ExStart state
- Exchange state
- Loading state
- Full state
Operational State where no Hello packets are received; therefore the router sends Hello packets
Down State
Operational State where Hello packets are received from the neighbor containing the Router ID of the sending router
Init State
Operational State that communicates between the two routers
Two-way State
Operational State where the two routers seen in point-to-point networks decide which router will initiate the DBD packet exchange and decide upon the initial DBD packet sequence number
ExStart State
Operational State where routers exchange DBD packets
Exchange State
Operational State where LSRs and LSUs are used to gain additional route information.
Loading State
Operational State wherein the link-state database of the router is fully synchronized
Full State
A router that is neither the DR nor the BDR.
DROTHER
