Chapter 3 Networking

Front 1

what is the first critical function of the transport layer?

Back 1

The internet's transport layer transports application layer messages between application endpoints.

Front 2

What two protocols are repsponsible for givng the transport layer additional delivery service beyond the network layer's IP protocol?

Back 2

TCP/UDP

Front 3

True or False? transport layer protocols are implemented by network devices such as routers and switches?

Back 3

False

Front 4

Breaking application messages into smaller chunks and adding a transport layer header to each chunk describes the creation of what?

Back 4

segment

Front 5

The transport layer sends a segment to the network layer.what does the network layer do with the segment? what does this result in?

Back 5

in a source host passes a transport-layer segment and a destination address to the network layer. The network layer then provides the service of delivering the segment to the transport layer in the destination host.

Front 6

A network router use what fields in the datagram?

Back 6

network routers only act on the network layer fields of the datagram, that is they do not examine the fields of the transport layer segment encapsulated with the datagram. On the receiving side, the network layer extracts the transport layer segment from the datagram and passes the segment up to the transport layer. The transport layer then processes the received segment, making the data in the segment available to the receiving application.

Front 7

The network layer provides logical communication between___________?

Back 7

hosts

Front 8

The transport layer provides logical communication between__________?

Back 8

between application processes running on different hosts.

Front 9

what is the most fundamentally responsibility between the transport layer and the network layers?

Back 9

TCP is used where a reliable connection is required while UDP is used in case of unreliable connections.

Front 10

In a few sentences describe the IP protocol layer

Back 10

celebrated IP Protocol, which defines

the fields in the datagram as well as how the end systems and routers act on these

fields. There is only one IP protocol, and all Internet components that have a net-
work layer must run the IP protocol. The Internet’s network layer also contains rout-
ing protocols that determine the routes that datagrams take between sources and

destinations. Although the network layer contains both the IP protocol and numerous routing protocols, it is often simply referred to as the IP layer, reflecting the fact that IP is the glue that binds the Internet together.

Front 11

Extending host to host delivery to process to process delivery is called?

Back 11

called transport-layer multiplexing and

demultiplexing.

Front 12

what two services does UDP provide?

Back 12

The UDP protocol provides a con-
nectionless service to its applications. This is a no-frills service that provides no

reliability, no flow control, and no congestion control.

Front 13

What two services does TCP provide?

Back 13

TCP provides a

connection-oriented service to its applications. This service includes guaranteed

delivery of application-layer messages to the destination and flow control (that is,

sender/receiver speed matching). TCP also breaks long messages into shorter seg-
ments and provides a congestion-control mechanism, so that a source throttles its

transmission rate when the network is congested.

Front 14

what is demuliplexing?

Back 14

demultiplexing, that is,

extending the host-to-host delivery service provided by the network layer to a

process-to-process delivery service for applications running on the hosts. In order to

keep the discussion concrete,

Front 15

what is multiplexing?

Back 15

to create segments, and passing the segments to the network

layer is called multiplexing.

Front 16

A UDP socket is fully identified by what two fields?

Back 16

no handshake and is connectionless

Front 17

A TCP socket is identifiable by what four fields?

Back 17

header, source,destination,IP address

Front 18

what is the utility of NMAP?

Back 18

Determining which applications are listening on which ports is a relatively easy

task.

Front 19

how would a web server utilize "Threads"?

Back 19

Web servers often use only

one process, and create a new thread with a new connection socket for each new

client connection. (A thread can be viewed as a lightweight subprocess.)

Front 20

Why is UDP described as a connectionless service?

Back 20

is a data transmission method used in packet switching networks by which each data unit is individually addressed and routed based on information carried in each unit, rather than in the setup information of a prearranged, fixed data channel as inconnection-oriented communication.

Front 21

how many bytes of overhead is the TCP segment?

Back 21

20 bytes

Front 22

how many bytes of overhead is UDP?

Back 22

8 bytes

Front 23

what are the four fields of the in the UDP segment?

Back 23

source port, dest port, length, checksum

Front 24

Describe the GBN protocol

Back 24

the sender is allowed to transmit multiple packets

(when available) without waiting for an acknowledgment, but is constrained to have no

more than some maximum allowable number, N, of unacknowledged packets in the

pipeline. We describe the GBN protocol in some detail in this section. But before read-
ing on, you are encouraged to play with the GBN applet (an awesome applet!) at the

companion Web site.

Front 25

what are three events must a GBN sender respond to?

Back 25

invocation from above,receipt of an ACK, a timeout event

Front 26

how does the SR protocol differ from the GBN protocol?

Back 26

With selective repeat, the sender sends a number of frames specified by a window size even without the need to wait for individual ACK from the receiver as in go-back-n ARQ.

Front 27

who is Vinton Cerf?

Back 27

Vinton Cerf and Robert Kahn,

recognized the importance of interconnecting these networks and invented a cross-
network protocol called TCP/IP, which stands for Transmission Control

Front 28

describe the 3 way handshake

Back 28

The TCP three-way handshake in Transmission Control Protocol (also called the TCP-handshake; three message handshake and/or SYN-SYN-ACK) is the method used by TCP set up a TCP/IP connection over an Internet Protocol based network.

Front 29

Describe MSS and MTU and how they are used?

Back 29

is a standardized technique incomputer networking for determining the maximum transmission unit (MTU) size on the network path between two Internet Protocol (IP) hosts, usually with the goal of avoiding IP fragmentation.

Front 30

The ethernet MSS is of what size?

Back 30

1,500 bytes

Front 31

Describe/identify fields in the TCP segment structure

Back 31

1.TCP Header Length

2.URG(urgent)

3.The sequence number field

4.The flag field

5.Source and Destination

6.Reveive Window

7.Checksum

Front 32

Describe the TCP sequence number and how it is created

Back 32

TCP has a 32-bit sequence number

field, where TCP sequence numbers count bytes in the byte stream rather than packets.

.

Front 33

describe the TCP Acknowledgement number

Back 33

idk

Front 34

What is meant by cumulative acknowledgement in TCP?

Back 34

In our GBN protocol, an acknowledgment for a packet with sequence number n will be taken to be a cumulative acknowledgment, indicating that all packets with a sequence number up to and including n have been correctly received at the receiver.

Front 35

Why and how is doubling the timeout interval used in TCP?

Back 35

who knows