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In OSPF, what is a grouping of contiguous networks and routers called?
OSPF area
How do OSPF routers become neighbours/adjacent?
When each router sees the other\\\'s HELLO packets.
Commands to enable OSPF process 1 on router connected to 10.0.0.0 in area 0?
router ospf 1 network 10.0.0.0 0.255.255.255 area 0 (If single area, area is always 0)
What is OSPF routers in area 0 called?
Backbone router.
1) What is OSPF router connecting area 0 and other area called?
1) ABR (Area Border Router).
2) What is OSPF router connecting to other AS called?
2) ASBR (Autonomous System Boundary Router).
What is OSPF router which is elected to spread /receive routing info to/from remaining routers called?
DR (Designated Router)
What is OSPF router which is standby for DR called?
BDR (Backup Designated Router)
What is OSPF data packet containing link-state and routing information to maintain topological database?
LSA (Link State Advertisement)
What is algorithm OSPF use to calculate best/shortest path?
SPF (Shortest Path First)
What is default OSPF Hello and Dead timers?
OSPF Hello - 10 secs OSPF Dead - 40 secs
What is OSPF Hello multicast address?
224.0.0.5 224.0.0.6 (DR)
Commands to change priority of int f0/1 to 2?
int f0/1 ip ospf priority 2
Commands to configure a loopback int using 172.16.10.1?
int loopback 0 ip address 172.16.10.1 255.255.255.255 no shutdown (255.255.255.255 is Host Mask)
In OSPF, what is list of all OSPF routers for which Hello packets have been seen, i.e. adjacency table?
Neighbor table.
In OSPF, what is list of all of LSA packets received for an area, i.e. link-state table?
Topology table.
What is OSPF forwarding table called?
Routing table.
What 2 types of network have DR and BDR assigned?
Broadcast & NBMA (no Point-to-Point/Multipoint types)
Commands to set OSPF cost 10 for both f0/1 and f0/2 to load-balance?
int f0/1 ip ospf cost 10 int f0/2 ip ospf cost 10
Commands to configure OSPF plain-text authentication using password cisco on s0/0?
int s0/0 ip ospf authentication-key cisco ip ospf authentication ! router ospf 1 area 0 authentication
Commands to configure OSPF MD5 authentication for key 1 using password cisco on s0/0?
int s0/0 ip ospf message-digest-key 1 md5 cisco ip ospf authentication message-digest ! router ospf 1 area 0 authentication message-digest
Command to display lists the OSPF area in which the interface belongs, neighbors adjacent on the interface, DR/BDR election process, and if authentication is configured?
show ip ospf interface
Command to show list of OSPF neighbors per inteface basis and adjacency state including DR/BDR?
show ip ospf neighbor
Command to analise OSPF events, showing messages for each OSPF packet?
debug ip ospf events
Command to show log messages that describe the contents of all OSPF packets?
debug ip ospf packets
Command to display messages describing OSPF Hello packets and Hello failures?
debug ip ospf hello
Command to show the authentication process if OSPF authentication is configured. Hello packet options match.
debug ip ospf adj (adj = adjacencies)
Command to display topology database (number of routers in AS and nighbouring router\\\'s ID), showing only OSPF routers unlike EIGRP topology table.
show ip ospf database
Command to change RID to 1.1.1.1 in OSPF 1?
router ospf 1 router-id 1.1.1.1 (loopback int will not overide this)
What is OSPF metric?How to calculate it?
Bandwidth/cost10*8/bandwidth (10*8/64000=1562)
What is the state of a route when Hold Down Timer is set?
Possibly down
How often does OSPF send routing updates?
Only when changes are made.
Command to restart OSPF process without rebooting router?
clear ip ospf process
How many LSAs exist in OSPF?What are Type1 and Type2?
8.Type1 = Router LSA generated by routerType2 = network LSA generated by DR/BDR
What does AuType set to 0/1/2 mean?
0) Authentication is Null1) Authentication is Plain-text2) Authentication is MD5
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