Final Exam

Question 1

The receiving side encapsulates segments
into datagrams.

Answer

true

Question 2

The receiving side delivers
segments to the transport
layer.

Answer

true

Question 3

Network layer protocols
are in

Accepted Answer

every host, router

Answer

most hosts, but all routers

Answer

not in routers but in end systems

Answer

edge routers between ISPs

Question 4

A router examines header
fields in all IP datagrams
passing through it.

Answer

true

Question 5

Network-layer functions:

Accepted Answer

forwarding: move packets
from router’s input to
appropriate router output

Accepted Answer

routing: determine route
taken by packets from
source to destination

Answer

routing: multiplexing and
demultiplexing

Answer

forwarding: use header info to deliver
received segments to correct
socket

Question 6

Traditional routing algorithms on a Per-router control plane:

Routing algorithm components can be (are almost always) different in each and every router within the control plane.

Answer

true

Question 7

Software-defined networking
(SDN): implemented in
(remote) servers:

Logically centralized control plane
A distinct (typically remote) controller interacts with local
control agents (CAs)

Answer

true

Question 8

DCHP does not stand for Dynamic Host Configuration Protocol.

Answer

true

Question 9

Physical network ports are the same ports as in the transport layer.

Answer

true

Question 10

Transport layer uses software ports which are different from the physical ports of the network layer.

Answer

true

Question 11

IP headers include:

Accepted Answer

source IP address

Accepted Answer

destination IP address

Accepted Answer

metadata needed to route and deliver the datagram

Answer

multi-hop router addresses

Answer

MAC address of the source

Question 12

DHCP (Dynamic Host Configuration Protocol) uses:

Accepted Answer

UDP

Accepted Answer

IP

Answer

TCP

Answer

MX

Answer

DASH

Question 13

A DHCP (Dynamic Host Configuration Protocol) server enables computers to request IP addresses and networking parameters automatically from the Internet service provider (ISP).

Answer

true

Question 14

IP Broadcast:

Accepted Answer

Request for IP address is broadcast

Accepted Answer

Response for IP address is unicast

Answer

Response for IP address is broadcast

Answer

Request for IP address is unicast

Question 15

The types of switching fabrics:

Accepted Answer

memory

Accepted Answer

bus

Accepted Answer

crossbar

Answer

storage

Answer

buffer

Question 16

Switching rate: rate at which packets can be
transferred from inputs to outputs

Answer

true

Question 17

What do Switching Fabrics do?

Accepted Answer

transfer packet from input buffer to appropriate
output buffer

Answer

transfer datagrams from transport layer to network layer

Answer

send frames between access points

Question 18

Devices within a subnet can't physically reach
each other without an
intervening router.

Answer

true

Question 19

Different subnets require a router to reach each other.

Answer

true

Question 20

An isolated network is called a:

Accepted Answer

subnet

Answer

access point

Answer

gateway

Answer

edge system

Question 21

CIDR: Classless InterDomain Routing

What part of an address is the number of bits for the subnet portion of an address, when the address format is "a.b.c.d/x"?

Accepted Answer

x

Answer

d

Answer

b

Answer

c.d

Question 22

DHCP: Dynamic Host Configuration Protocol

When an host dynamically obtains its IP address from the network sever is keeps that address and stores it in memory.

Answer

true

Question 23

DCHP can return more than just allocated IP address on a subnet.

Answer

true

Question 24

DHCP can return:

Accepted Answer

address of first-hop router for client

Accepted Answer

name and IP address of DNS sever

Accepted Answer

network mask (indicating network versus host portion
of address)

Accepted Answer

IP address for host

Answer

name and IP address of MAC

Answer

address of lost-hop router for client

Question 25

NAT stands for Network Address Translation

Answer

true

Question 26

NAT: Local network uses different IP addresses for each device as far as outside wold is concerned.

Answer

true

Question 27

NAT: network address translation

Accepted Answer

Range of addresses not needed from ISP: just one
IP address for all devices

Accepted Answer

Can change ISP without changing addresses of
devices in local network

Accepted Answer

devices inside local net not explicitly addressable,
visible by outside world (a security plus)

Answer

Range of addresses is needed from ISP: 
IP addresses for all devices

Question 28

WAN stands for wide area network and LAN stands for Local Area Network

Answer

true

Question 29

IPv6 motivation:

Accepted Answer

32-bit address space soon to be
completely allocated. 128 bit addresses (16 bytes) in IPv6

Accepted Answer

header format helps speed up
processing/forwarding
• fixed-length 40 byte header
• no fragmentation allowed
• checksum removed entirely to reduce processing time at
each hop

Answer

32-bit address space soon to be
completely allocated. 64 bit addresses (16 bytes) in IPv6

Answer

header format helps speed up
processing/forwarding
• fixed-length 32 byte header
• no fragmentation allowed
• checksum removed entirely to reduce processing time at
each hop

Question 30

IP datagrams have only the destination IP address

Answer

true

Question 31

Tunneling: An IPv6 datagram can be carried as a payload in an IPv4 datagram on IPv4 routers.

Answer

true

Question 32

A logically centralized (SDN) routing controller distributes:

Accepted Answer

flow table: headers, counters, actions

Answer

forwarding table

Answer

return table

Question 33

Network layer functions:

forwarding: move packets
from router’s input to
appropriate router output

data plane

Answer

true

Question 34

Network layer functions:

routing: determine route
taken by packets from source
to destination

control plane

Answer

true

Question 35

A sequence of routers' packets will traverse in
going from a given initial source host to a given final
destination host. This is called:

Accepted Answer

path

Answer

network

Answer

graph

Answer

vector

Question 36

Global or decentralized?

Accepted Answer

“link state” algorithms: all routers have complete
topology, link cost info

Accepted Answer

Dijkstra's algorithm: all routers have complete
topology, link cost info

Accepted Answer

“distance vector” algorithms: router knows physically-connected neighbors, link
costs to neighbors

Accepted Answer

“distance vector” algorithms: iterative process of
computation, exchange of
info with neighbors

Answer

“distance vector” algorithms: all routers have complete
topology, link cost info

Answer

Dijkstra's algorithm: iterative process of
computation, exchange of
info with neighbors

Question 37

Dijkstra's algorithm is n(n+1)/2 comparisons: O(n^2)

Answer

true

Question 38

Distance vector algorithm: If any router notices link cost change:

Accepted Answer

All routers recompute.

Answer

Only the routers noticing the change recompute.

Answer

Only the changed router(s) recompute.

Question 39

Distance vector algorithm can result in transient loops because all routers try to recompute distance and incorrectly update and get stuck "correcting".

Answer

true

Question 40

Dijkstra's algorithm can result in transient loops because all routers try to recompute distance and incorrectly update and get stuck "correcting".

Answer

true

Question 41

Distance vector alogrithm:

Constantly, each node sends its own
distance vector estimate to neighbors

Answer

true

Question 42

Distance vector algorithm each node notifies
neighbors when its
DVis not changing.

Answer

true

Question 43

DV:

Accepted Answer

each node’s table used by
others

Answer

each node computes only its
own table

Question 44

AS does not stand for Autonomous System.

Answer

true

Question 45

All routers in the world must run
same intra-domain protocol.

Answer

true

Question 46

Intra-AS means between AS's.

Answer

true

Question 47

Which of these are Inter-AS protocols?

Accepted Answer

BGP

Answer

RIP

Answer

IGRP

Answer

OSPF

Question 48

Output port Buffering on a router:

How much buffering is the rule of thumb?

Accepted Answer

RTT(typical)*C(link capacity)

Answer

RTT*2

Answer

W*2

Answer

processing time + forwarding time

Question 49

What happens when a large IP datagram gets "fragmented" (divided) within a net?

Accepted Answer

one datagram becomes
several datagrams

Accepted Answer

“reassembled” only at
final destination

Accepted Answer

IP header bits used to
identify, order related
fragments

Answer

the datagram is corrupted and loss occurs

Answer

Transport header is used to determine source port

Answer

“reassembled” at each switch or connected router

Question 50

A router is designed as:

Accepted Answer

input ports, switching fabrics, output ports on the forwarding data plane and a routing processor on control plane.

Answer

switching fabrics, input ports, output ports

Answer

input ports, switching fabrics, output ports

Answer

switching fabrics, input ports, output ports, switching fabrics

Answer

input ports, output ports

Question 51

What does CIDR stand for?

Accepted Answer

Classless InterDomain Routing

Answer

Configuration InterDomain Routing

Answer

Classless InterDomain Ranging

Question 52

What is the router located at the "edge" of its own AS, with links to a router or routers in other AS'es called?

Accepted Answer

Gateway router

Answer

Edge router

Answer

Edge system

Answer

inter router

Question 53

Forwarding tables are configured by both intra and inter AS routing algorithms.

Answer

true

Question 54

Intra-AS forwarding tables determine entries for
external destinations.

Answer

true

Question 55

IGP and BGP stand for:

Accepted Answer

interior gateway protocol and border gateway protocol

Answer

inside group protocol and border gateway protocol

Answer

inter gateway protocol and beyond gateway protocol

Question 56

A home network is an AS.

Answer

true

Question 57

Common intra-AS routing protocols:

Accepted Answer

RIP

Accepted Answer

IGRP

Accepted Answer

OSPF

Answer

BGP

Answer

IP

Answer

TCP

Answer

IRYP

Question 58

OSPF (Open Shortest Path First) intra-AS routing protocol uses Dijkstra's algorithm, therefore a topology map is at each node.

Answer

true

Question 59

OSPF routers flood OSPF link-state advertisements to all other routers in entire AS.

Answer

true

Question 60

BGP (Border Gateway Protocol):

Accepted Answer

inter-domain

Accepted Answer

Only tells you which AS to go through and nothing actually about the 
AS

Accepted Answer

allows subnet to advertise its existence to the rest of the Internet

Accepted Answer

propagate reachability information to all AS internal routers

Answer

intra-domain

Question 61

The protocol that makes the internet possible is:

Accepted Answer

BGP

Answer

IP

Answer

TCP

Answer

OSPF

Question 62

BGP has two important attributes:
• AS-PATH: list of AS'es through which prefix advertisement
has passed
• NEXT-HOP: gateway router that advertised the route

Answer

true

Question 63

BGP messages use:

Accepted Answer

TCP

Answer

UDP

Answer

OSPF

Question 64

Host and routers use ICMP (Internet Control Message Protocol) to communicate network-level information. ICMP messages are carried in IP datagrams to notify of some type of networking error or something similar.

Answer

true

Final Exam

Erstelle ein kostenloses Konto, um dieses Quiz zu beenden

Fragen in diesem Quiz (81)

Informationen

Feedback

Wie gefällt dir das neue Design?