Chapter 21 Flashcards
2-way state
2-way state
In OSPF, a neighbor state that implies that the router has exchanged Hellos with the neighbor and that all required parameters match.
Area Border Router (ABR)
Area Border Router (ABR)
A router using OSPF in which the router has interfaces in multiple OSPF areas.
backbone area
backbone area
In OSPFv2 and OSPFv3, the special area in a multiarea design, with all nonbackbone areas needing to connect to the backbone area, area 0.
convergence
convergence
The time required for routing protocols to react to changes in the network, removing bad routes and adding new, better routes so that the current best routes are in all the routers’ routing tables.
distance vector
distance vector
The logic behind the behavior of some interior routing protocols, such as RIP. Distance vector routing algorithms call for each router to send its entire routing table in each update, but only to its neighbors. Distance vector routing algorithms can be prone to routing loops but are computationally simpler than link-state routing algorithms.
Dead Interval
In OSPF, a timer used for each neighbor. A router considers the neighbor to have failed if no Hellos are received from that neighbor in the time defined by the timer.
designated router (DR)
In OSPF, on a multiaccess network, the router that wins an election and is therefore responsible for managing a streamlined process for exchanging OSPF topology information between all routers attached to that network.
Dijkstra Shortest Path First (SPF) algorithm
Dijkstra Shortest Path First (SPF) algorithm
The name of the algorithm used by link-state routing protocols to analyze the LSDB and find the least-cost routes from that router to each subnet.
full state
full state
In OSPF, a neighbor state that implies that the two routers have exchanged the complete (full) contents of their respective LSDBs.
fully adjacent
fully adjacent
In OSPF, a characterization of the state of a neighbor in which the two neighbors have reached the full state.
Hello Interval
Hello Interval
With OSPF and EIGRP, an interface timer that dictates how often the router should send Hello messages.
interior gateway protocol (IGP)
interior gateway protocol (IGP)
A routing protocol designed to be used to exchange routing information inside a single autonomous system.
link-state
link-state
A classification of the underlying algorithm used in some routing protocols. Link-state protocols build a detailed database that lists links (subnets) and their state (up, down), from which the best routes can then be calculated.
internal router
internal router
In OSPF, a router with all interfaces in the same nonbackbone area.
link-state advertisement (LSA)
link-state advertisement (LSA)
In OSPF, the name of the data structure that resides inside the LSDB and describes in detail the various components in a network, including routers and links (subnets).
link-state database (LSDB)
link-state database (LSDB)
In OSPF, the data structure in RAM of a router that holds the various LSAs, with the collective LSAs representing the entire topology of the network.
Link-State Update
Link-State Update
An OSPF packet used to send an LSA to a neighboring router.
metric
metric
A unit of measure used by routing protocol algorithms to determine the best route for traffic to use to reach a particular destination.
multiarea OSPF
multiarea OSPF
In OSPFv2 and OSPFv3, a design that uses more than one area within one OSPF domain (typically a single company).
neighbor
neighbor
In routing protocols, another router with which a router decides to exchange routing information.
routed protocol
routed protocol
A protocol that defines packets that can be routed by a router. Examples of routed protocols include IPv4 and IPv6.
router ID (RID)
router ID (RID)
In EIGRP and OSPF, a 32-bit number, written in dotted-decimal notation, that uniquely identifies each router.
router LSA
router LSA
In OSPF, a type of LSA that a router creates to describe itself and the networks connected to it.
shortest path first (SPF) algorithm
shortest path first (SPF) algorithm
The name of the algorithm used by link-state routing protocols to analyze the LSDB and find the least-cost routes from that router to each subnet.
single-area OSPF
single-area OSPF
In OSPFv2 and OSPFv3, a design that uses a single area within one OSPF domain (typically a single company).
summary LSA
summary LSA
In OSPFv2, a type of LSA, created by an Area Border Router (ABR), to describe a subnet in one area in the database of another area.
