ospf Flashcards
protocols that define packet structure are known as
routed protocols
protocols design for use in one AS
interior gateway protocol
protocols intended for use between AS
exterior gateway protocol BGP
have ASNs assigned by IANA
Kinds of IGPs
Distance Vector
Advanced Distance Vector i.e. eigrp
Link state i.e ospf
what metric does rip v2 use
hops
what metric used by ospf
the sum of all interface costs in a route, and bandwidth
metric used by eigrp
uses bandwidth and delay
Convergence of RIP, EIGRP and OSPF
slow fast fast
does ripv1 support vlsm
no but ripv2 does
what is ad
the believability of the routing protocol. WHich takes precendence. lower better
default ad connected
0
default ad static
1
default ad bgp ext
20
default ad eigrp internal
90
default ad igrp
100
default ad ospf
110
default ad is-is
115
default ad rip
120
default ad eigrp ext
170
default ad bgp iint
200
default ad shcp default
254
3 state ospf
becoming neighbours via Hellos
exchanging dbs
adding best routes (using spf)
command to show neighbors
show ip ospf neighbor
multicast addr for ospf speakers
224.0.0.5
do they check their lists for LSAs they already have
yes
how do you know if neighbor has failed
hasnt sent hello for longer than the dead interval
do neighbors reflood every 25 mins
no 30 mins you dumb fuk
OSPF use DR and BDR on ethernet links true or false
true
multicast address to all DRs
224.0.0.6
why do we use ospf areas
larger topology requires more memory
processing power required frows exponentially
Types of LSAs in ospf area
Router LSA for each in the area
Network LSA for each with a DR + 1 neighbor
Summary LSA for subnet IDs in other areas
Type 1 LSA
RID, ints, IP, mask, int status
Type 2 LSA
DR/BDR, IPs, subnet id, mask
Type 3 LSA
sub ids, mask, RID of bridge router
