Cs 456

Front 1

All the devices such as computers, webcams, TVs, connected to the internet are called ____ or _____.

Back 1

hosts, end systems

Front 2

Fiber, copper, radio,
satellite are ____.

Back 2

communication links

Front 3

transmission rate is also known as

Back 3

bandwidth

Front 4

What does a packet switch do?

Back 4

A packet switch takes a packet arriving on one of its incoming communication links and forwards that packet on one of its outgoing communication links.

Front 5

the two most prominent types in
today’s Internet are ____

Back 5

routers and link-layer switches.

Front 6

The sequence of__________ and___________ traversed by a packet from the sending end system to the receiving end system is known as a route or path.

Back 6

communication links

packet switches

Front 7

What does the IP protocol specify?

Back 7

specifies the format of the packets that are sent and received among routers and end systems

Front 8

Internet standards are developed by the_____

Back 8

Internet Engineering Task Force

Front 9

The IETF standards documents are called ______

Back 9

requests for comments (RFCs)

Front 10

They define protocols such as TCP, IP,
HTTP (for the Web), and SMTP (for e-mail). What are they?

Back 10

RFCs

Front 11

Some applications are said to be_______ , since they involve multiple
end systems that exchange data with each other

Back 11

distributed applications

Front 12

What does a protocol define?

Back 12

defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event

Front 13

Hosts are devided into

Back 13

clients and servers

Front 14

Servers usually reside in large _____.

Back 14

data centers

Front 15

the network that physically connects an end
system to the first router is called a

Back 15

access network

Front 16

applications and end systems are at the

Back 16

edge of the network

Front 17

DSLAM stands for

Back 17

digital subscriber line access multiplexer

Front 18

The analog signals from many such houses are translated back into digital format at the ___

Back 18

DSLAM

Front 19

the customer side, a ____ separates the data and telephone signals arriving to the home and forwards the data signal to the DSL modem

Back 19

splitter

Front 20

What is an HFC?

Back 20

Because both fiber and coaxial cable are employed in this system, it is often referred to as hybrid fiber coax

Front 21

At the cable head end, the ______ serves a similar function as the DSL network’s DSLAM

Back 21

cable modem termination system (CMTS)

Front 22

In HFC system, at the _____ , the ______ serves a similar function as the DSL network’s DSLAM.

Back 22

cable head end

Front 23

Why is DSL and cable asymmetric?

Back 23

Because the downstream and upstream rates are different

Front 24

How does DSL connect to the CO?

Back 24

dedicated access to central office

Front 25

In HFC, how are homes connected to cable headends?

Back 25

homes share access network to cable headend

Front 26

Central office is for ____ and headend is for ___.

Back 26

DSL,

Cable internet

Front 27

What is guided media?

Back 27

signals propagate in solid
media: copper, fiber, coax

Front 28

What is unguided media?

Back 28

signals propagate freely,
e.g., radio

Front 29

_______ can be used as a guided shared medium

Back 29

Coaxial cable

Front 30

coaxial cable are made of two_____ copper
conductors

Back 30

concentric

Front 31

coaxial cable are made of two concentric ____

Back 31

copper conductors

Front 32

What are two types of satellites?

Back 32

geosynchronous and low
altitude

Front 33

What is the time to transmit a packet?

Back 33

L bits

R bits/sec

L/R seconds = time sec

So, if a source end system or a packet
switch is sending a packet of L bits over a link with transmission rate R bits/sec, then
the time to transmit the packet is L/R seconds.

Front 34

What is Store-and-forward?

Back 34

Store-and-forward transmission means that the packet switch must receive
the entire packet before it can begin to transmit the first bit of the packet onto the
outbound link

Front 35

What is the end-to-end delay when using store-and-forward and having N links (N-1 routers)

Back 35

N*(L/R)

Front 36

If arrival rate (in bits) to link exceeds transmission rate of link for a period of time:

Back 36

 packets will queue, wait to be transmitted on link
 packets can be dropped (lost) if memory (buffer) fills up

Front 37

what are the two core-network functions?

Back 37

routing and forwarding

Front 38

What is forwarding?

Back 38

forwarding: move packets from
routerʼs input to appropriate
router output

Front 39

What is routing?

Back 39

determines source-destination route taken by
packets

Front 40

In______ networks, the resources needed along a path (buffers, linktransmission rate) to provide for communication between the end systems are
reserved for the duration of the communication session between the end systems.

Back 40

circuit-switched

Front 41

In______ networks, the resources needed along a path (buffers, link transmission rate) to provide for communication between the end systems are
NOT reserved for the duration of the communication session between the end systems.

Back 41

packet-switched

Front 42

In _____ a session’s messages
use the resources on demand, and as a consequence, may have to wait (that is,
queue) for access to a communication link

Back 42

packet-switched network

Front 43

Tier-1 ISPs are similar to ______

Back 43

our (imaginary)
global transit ISP

Front 44

a third-party company can create an Internet Exchange Point (IXP) (typically in a stand-alone building with its own switches), which is a
____________ .

Back 44

meeting point where multiple ISPs can peer together.

Front 45

a third-party company can create an _______ (typically in a stand-alone building with its own switches), which is a meeting point where multiple ISPs can peer together.

Back 45

Internet Exchange Point (IXP)