The next three problems are based on this assumption:

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Chapter 8.

1.

ARP cache contains…

a list of IP addresses and their corresponding MAC addresses

2.

FFFFFFFFFFFF
… is the broadcast MAC address.

3.

ARP cache uses the broadcast MAC address to …

find the corresponding MAC address of a given IP address in
the local netw
ork

4.

Whenever a switch receives a frame with the broadcast MAC address, it will …

forward the frame to all other
ports in the switch

5.

Whenever a router receives a frame with the broadcast MAC address, it will …

block the frame

6.

A routing table contains …

info
rmation that is used by the router to route a packet it receives

The next three problems are based on this assumption:

Given the following routing table of a router:

Destination


Subnet Mask


Gateway

0.0.0.0



0.0.0.0



202.202.100.
1

202.202.1.0


255.255.2
55.0


0.0.0.0

202.202.2.0


255.255.255.0


0.0.0.0

202.202.3.0


255.255.255.0


0.0.0.0

202.202.4.0


255.255.255.0


0.0.0.0

7.

If the router receives a frame with destination IP address:
1
.
1
.
1
.1, where will the router forward the frame?

Gateway 202.202.100.1

8.

If

the router receives a frame with destination IP address: 202.202.
1
.144, where will the router forward the
frame?

A port connected to network
202.202.1.0

9.

If the router receives a frame with destination IP address: 202.202.
100
.1, where will the router forwa
rd the
frame?

Gateway 202.202.100.1

10.

Where does the metric value come from?

Determined and entered manually by the network administrator OR
computed and entered automatically by a dynamic routing algorithm

11.

What will a router do if it finds more than one rou
te to get to the same place? (3)

It will use the route whose
subnet mask has the most 1s. If that does not work, it will use the route with the lowest metric value. If that
does not work, it will use one of them arbitrarily.

12.

Assuming that route A has a met
ric value of 10 and route B has a metric value of 1. Assuming that both routes
go to the same place, which route will be used by the router to route a packet?

Route B since it has the lower
cost.

13.

What does a NAT do?

It will replace the private IP address i
n a packet with the public IP address.

14.

What is static NAT? What is dynamic NAT? What is overloaded NAT? In the overloaded NAT, … is used by the
NAT to forward a response/reply to the right computer behind the NAT.

Static NAT:

One private IP address is mapp
ed to a particular public IP address, and vice versa
. 100 computers
will need 100 public IP addresses


Dynamic NAT:

A number of computers are dynamically mapped to a pool of public IP addresses
. 100
computers can dynamically use 10 public IP addresses.

Ove
rloaded NAT:

A number of computers are dynamically mapped to a single public IP address
. 100
computers can dynamically use 1 public IP address.

Port number is used by the NAT to forward a response to the right computer behind the NAT.

15.

In an overloaded NAT,

to connect a Web server behind the NAT, we can use a technique called …

Port
forwarding.

16.

What are six major differences between static routing and dynamic routing?


Static

Dynamic

Manual

Using prescribed route

The chosen route may not be the
most

effi
cient

More secure due to path

predictability

Small network

Cannot adapt to the network
change or network failure

Automatic

Using routing metrics

The chosen route is the most efficient

Less secure because the chosen route
may include unknown, unsecured
path

Medium to large network

Can adapt to the network change or
network failure

17.

What dynamic routing protocols are included in the distance vector?

RIPv1, RIPv2, BGP

18.

True or False. The maximum number of routers in a network that uses RIP is 15.

19.

True or False.

The maximum number of hops in a network that uses RIP is 15.

20.

What is autonomous system?

A

group of routers that are controlled by a single administrator
, e.g., ISP,
and
that use a single routing protocol

21.

What is IGP?
Protocols used by r
outers WITHIN an Au
tonom
ous System
to
communicate
to one another
.
What is EGP?
Protocols used by r
outers BETWEEN Autonomous Systems (edge routers)
to
communicate
to
each other.
What is edge router?

R
outers connecting two Autonomous Systems
.

22.

What dynamic routing protocols are

included in the link state?

OSPF , IS
-
IS

23.

What are the advantages of the link state relative to the distance vector? (2)
Shari
ng the route change/update
only
mainly
w
hen there is a route change/update
, hence (1) f
ast to converge
, and (2) s
aving the network

bandwidth

24.

What dynamic routing protocol is hybrid of distance vector and link state?

EIGRP

25.

What is the meaning of “convergence” in the context of dynamic routing?

The state where the updating of the
routing tables for all the routers has completed

26.

What is

rollover/yost cable?

A cable to connect a computer to a router

t
o configure the router

27.

To connect a computer to a router, we can use … or … program.

PuTTY and HyperTerminal

28.

What is NMS?
Program displaying an overall view of a network (e.g., routers, switc
hes, nodes)
t
o monitor and
configure elements in the network

29.

What is traceroute?

Application software that sends a single packet to a host. As it progresses, it returns
information about every router between them

30.

TRUE or FALSE. A frame always contains MAC
address of the next hop. It does not always contain the MAC
address corresponding to the final destination IP address.

31.

TRUE or FALSE. A packet always contains the final destination IP address, not the “next hop” IP address

32.

TRUE or FALSE. The destination MA
C address always changes in every hop, while destination IP address stays
the same.