Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ClSC0 > final review > Flashcards

final review Flashcards

1
Q

PVST hello timer?

A

2 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

LLDP hold timer?

LLDP hello timer?

A

hold - 120 secs (x4)

hello - 30 secs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Root bridge’s interfaces have what cost?

A

0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

PVST takes 50 seconds by default, because of what 3 other timers?

A

15s - learning state timer
15s - delay timer
20s - max age timer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how is EIGRP metric calculated?

A

lowest segment bandwidth

sum of segment delays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

EIGRP routing table contains only what?

A

successors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is a successor?

A

best path to destination network.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is a feasible successor?

A

best loop-free backup route with lower AD than successor’s advertised distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is a feasible distance?

A

the best metric along a path (advertised + next hop)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is an advertised distance?

A

the metric advertised by the next hop router

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how is OSPF metric calculated?

A

Cost/metric = Reference Bandwidth of 100 Mbps divided by interface bandwidth.

(For example, in the case of 10 Mbps Ethernet , OSPF Metric Cost value is 100 Mbps / 10 Mbps = 10)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the default CDP hold/announcements timer?

A

hold - 180 secs (x3)

announcement - 60 sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What kind of errors will you see in Duplex Mismatch?

A
  • The half-duplex side of the link will experience increased collision rates
  • The full-duplex side of the link will have a large number of CRC errors.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What can cause down/down?

A

bad cable/connector, speed mismatch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the difference between an OSPF ABR and ASBR?

A

ABR - Area Border Router, lets OSPF router know the edges of an OSPF area.

ASBR - Autonomous System Border Router, lets devices know end of AS and where default gateway is located.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the only dhcp command that doesn’t need ‘ip’ at the start?

A

(dhcp-config)#domain-name example.com

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which OSPF network types have a default hello/dead timer of 10/40 seconds?

A
  • broadcast

- point-to-point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which OSPF network types have a default hello/dead timer of 30/120 seconds?

A

-non-broadcast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What OSPF network type is enabled by default for FDDI and Ethernet interfaces?

A

broadcast

20
Q

What OSPF network type is enabled by default for HDLC and PPP serial interface?

A

point-to-point

21
Q

What OSPF network type is enabled by default for X.25 and frame relay interface?

A

non-broadcast

22
Q

Router stuck in exstart/exchange

A

MTU mismatch/duplicate IDs

23
Q

router stuck in loading

A

corrupted LSR/MTU mismatch

24
Q

all routers stuck in 2-way state

A

check if all have priority 0

2-way is normal state between DROTHERs

25
Q

router stuck in init state

A

has sent hellos, but can’t receive them

or cant receive neighbors’ router ID

26
Q

What is an LSDB?

A

Link state database, contains LSAs for each link in the OSPF area. Knows router IDs, the cost, and network ID/prefix for each link.

The LSDB is identical for all routers in an area, different one for each area.

27
Q

What does an LSA do?

A

Routers flood them to all neighbors until all routers in an OSPF area develop the same map of the network.

28
Q

What information does an LSA contain?

A

the router ID of the sender
the cost of the link
the network address and prefix of the advertised link

29
Q

How long do LSAs last?

A

Aging timer is 30 mins by default, LSA flooded again after expiration.

30
Q

What is the backbone area?

A

area 0; all other areas must connect to it

31
Q

What is the difference between an internal router, backbone router, and area border router?

A

Internal routers have all interfaces within a single area.

ABRs have interfaces in two or more areas.

Backbone routers are connected to the backbone area 0.

32
Q

What command should you use on an OSPF router interface that has no OSPF neighbors?
Why?

A

(if)#passive-interface
It allows the router to send LSAs out of that interface, but prevents it from sending OSPF hello messages, saving bandwidth.

33
Q

Difference between local route and connected route?

A
  • local routes are host routes, /32. They represent an exit interface.
  • connected route is an network route representing an adjacent link. /30.
34
Q

creates a new LSA for the default route and floods it to all interfaces

A

default-information originate

be sure to remember that it is ‘information’ not ‘route’

35
Q

How do you manually configure router ID, and what must you do afterwards to apply it to running config?

A

(config-router)# router-id 1.1.1.1

Afterwards use either:
reload command
clear ip ospf process (resets OSPF on the router, loses its routes)

36
Q

What is an ASBR?

Difference between ABR?

A

Autonomous system boundary router - connects the OSPF network o an external network, usually originates the default gateway to internet.

Area Backbone router is just a router in the backbone area 0.

37
Q

the OSPF network command does what?

A

specifies the interfaces to enable OSPF on, and what their area is

network 10.0.0.0 0.0.0.3 area 0

38
Q

How do you configure router id for OSPF?

A

router-id 1.1.1.1

do not specify ospf

39
Q

default reference bandwidth?

How do you change it?

A

100mbps

(config-router)# auto-cost reference-bandwidth 1000

40
Q

how do you find the cost of an interface?

A

show ip ospf interface f0/0
ref/int = cost
(ospf after ip)

41
Q

How do you calculate the cost of a route?

A

Sum of the cost of each exit interface along the path.

42
Q

Cost of loopback interface?

A

1.

Add one whenever destination is a loop back interface even though it isn’t a real exit interface.

43
Q

How do you manually configure cost, how does it interact with auto-cost reference-bandwidth?

A

ip ospf cost 100

it takes priority over auto calculated cost.

44
Q

What is an alternative way to enable OSPF on an interface?

A

(if)# ip ospf 1 area 0

if you use this command, the “routing for networks” in show ip protocols will be absent, and display interfaces explicit instead.

45
Q

What is similar about PPP and broadcast OSPF?

What is different?

A

They both have the same hello/dead timers, and can both dynamically discover neighbors.

PPP unlike broadcast does not elect DR/BDR.

46
Q

why do DROTHERs have a max of only 2 adjacency?

A

DROTHERs can only become adjacent with DR and BDR, they stay neighbors with the other DROTHERs because they cannot progress past the 2-way state.

ClSC0 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions