ENetwork Chapter 4

1 Refer to the exhibit. Host1 is in the process of setting up a TCP session with Host2. Host1

has sent a SYN message to begin session establishment. What happens next?

Host1 sends a segment with the ACK flag = 0, SYN flag = 0 to Host2.

Host1 sends a segment with the ACK flag = 1, SYN flag = 0 to Host2.

Host1 sends a segment with the ACK flag = 1, SYN flag = 1 to Host2.

Host2 sends a segment with the ACK flag = 0, SYN flag = 1 to Host1.

Host2 sends a segment with the ACK flag = 1, SYN flag = 0 to Host1.

*Host2 sends a segment with the ACK flag = 1, SYN flag = 1 to Host1.

2 Why is flow control used for TCP data transfer?

to synchronize equipment speed for sent data

to synchronize and order sequence numbers so data is sent in complete numerical order

*to prevent the receiver from being overwhelmed by incoming data

to synchronize window size on the server

to simplify data transfer to multiple hosts

3 Refer to the exhibit. What two pieces of information can be determined from the output that

is shown? (Choose two.)

*The local host is using three client sessions.

*The local host is using web sessions to a remote server.

The local host is listening for TCP connections using public addresses.

The local host is using well-known port numbers to identify the source ports.

The local host is performing the three-way handshake with 192.168.1.101:1037.

4 Which event occurs during the transport layer three-way handshake?

The two applications exchange data.

*TCP initializes the sequence numbers for the sessions.

UDP establishes the maximum number of bytes to be sent.

The server acknowledges the bytes of data received from the client.

5 During a TCP communication session, if the packets arrive to the destination out of order,

what will happen to the original message?

The packets will not be delivered.

The packets will be retransmitted from the source.

*The packets will be delivered and reassembled at the destination.

The packets will be delivered and not reassembled at the destination.

6 Which OSI model layer is responsible for regulating the flow of information from source to

destination, reliably and accurately?

application

presentation

session

*transport

network

7 Which is an important characteristic of UDP?

acknowledgement of data delivery

*minimal delays in data delivery

high reliability of data delivery

same order data delivery

8 With TCP/IP data encapsulation, which range of port numbers identifies all well-known

applications?

0 to 255

256 to 1022

*0 to 1023

1024 to 2047

49153 to 65535

9 What mechanism is used by TCP to provide flow control as segments travel from source to

destination?

sequence numbers

session establishment

*window size

acknowledgments

10 Based on the transport layer header shown in the diagram, which of the following

statements describe the established session? (Choose two.)

This is a UDP header.

*This contains a Telnet request.

This contains a TFTP data transfer.

The return packet from this remote host will have an Acknowledgement Number of 43693.

This is a TCP header.

11 Which transport layer protocol provides low overhead and would be used for applications

which do not require reliable data delivery?

TCP

IP

*UDP

HTTP

DNS

12 Refer to the exhibit. In line 7 of this Wireshark capture, what TCP operation is being

performed?

*session establishment

segment retransmit

data transfer

session disconnect

13 Which information is found in both the TCP and UDP header information?

sequencing

flow control

acknowledgments

*source and destination port

14 Why are port numbers included in the TCP header of a segment?

to indicate the correct router interface that should be used to forward a segment

to identify which switch ports should receive or forward the segment

to determine which Layer 3 protocol should be used to encapsulate the data

*to enable a receiving host to forward the data to the appropriate application

to allow the receiving host to assemble the packet in the proper order

15 Which two options represent Layer 4 addressing? (Choose two.)

identifies the destination network

identifies source and destination hosts

*identifies the communicating applications

*identifies multiple conversations between the hosts

identifies the devices communicating over the local media

16 Which three features allow TCP to reliably and accurately track the transmission of data

from source to destination? (Choose three.)

*flow control

urgent pointer

best effort delivery

*session establishment

connectionless services

*numbering and sequencing

17 What is dynamically selected by the source host when forwarding data?

destination logical address

source physical address

default gateway address

*source port

18 After a web browser makes a request to a web server that is listening to the standard port,

what will be the source port number in the TCP header of the response from the server?

13

53

*80

1024

1728

19 What are two features of the User Datagram Protocol (UDP)? (Choose two.)

flow control

*low overhead

*connectionless

connection-oriented

sequence and acknowledgements

20 Refer to the exhibit. Host A is using FTP to download a large file from Server 1. During the

download process, Server 1 does not receive an acknowledgment from Host A for several

bytes of transferred data. What action will Server 1 take as a result?

create a Layer 1 jam signal

*reach a timeout and resend the data that needs to be acknowledged

send a RESET bit to the host

What actions will occur after RouterA loses connectivity to network 114.125.16.0? (Choose two.)

**RouterB will include network 123.92.76.0 and 136.125.85.0 in its update to RouterA.During the next update interval, RouterB will send a RIP update out both ports that includes the inaccessible network.During the next update interval, RouterC will send an update to RouterB stating that network 114.125.16.0 is accessible in 2 hops.**Router C will learn of the loss of connectivity to network 114.125.16.0 from RouterB.RouterB will include network 123.92.76.0 and 136.125.85.0 in its update to RouterC.

2What does a router running RIP do first with a new route that is received from an advertisement?

places it immediately in the routing table**adjusts the metric for the new route to show the added distance for the routeadvertises this route out all other interfaces except the one that it came in onsends a ping packet to verify that the path is a feasible route

3

Refer to the exhibit. If all routers are using RIP, how many rounds of updates will occur before all routers know all networks?

12**3456

4Which of the following methods does split horizon use to reduce incorrect routing information?

Routing updates are split in half to reduce the update time.**Information learned from one source is not distributed back to that source.New route information must be learned from multiple sources to be accepted.The time between updates is split in half to speed convergence.New route information is suppressed until the system has converged.

5

Refer to the exhibit. The routers in this network are running RIP. Router A has not received an update from Router B in over three minutes. How will Router A respond?

The Holddown timer will wait to remove the route from the table for 60 seconds.**The Invalid timer will mark the route as unusable if an update has not been received in 180 seconds.The Update timer will request an update for routes that were learned from Router B.The Hello timer will expire after 10 seconds and the route will be flushed out of the routing table.

6

The graphic shows a network that is configured to use RIP routing protocol. Router2 detects that the link to Router1 has gone down. It then advertises the network for this link with a hop count metric of 16. Which routing loop prevention mechanism is in effect?

split horizonerror conditionhold-down timer**route poisoningcount to infinity

7Which two statements describe EIGRP? (Choose two.)

EIGRP can be used with Cisco and non-Cisco routers.**EIGRP sends triggered updates whenever there is a change in topology that influences the routing information.EIGRP has an infinite metric of 16.**EIGRP sends a partial routing table update, which includes just routes that have been changed.EIGRP broadcasts its updates to all routers in the network.

8Which event will cause a triggered update?

an update routing timer expiresa corrupt update message is received**a route is installed in the routing tablethe network is converged

9Which of the following statements are correct about RIP?

uses a broadcast to update all other routers in the network every 60 secondsuses a multicast address to update other routers every 90 seconds**will send out an update if there is a failure of a linkupdates only contain information about routes that have changed since last update

10Which two statements are true regarding the function of the RIPv1 routing updates? (Choose two).

updates are broadcast only when there are changes to the topology**updates are broadcast at regular intervalsbroadcast are sent to 0.0.0.0**broadcasts are sent to 255.255.255.255updates contain the entire network topologyonly changes are included in the updates

11A network administrator is evaluating RIP versus EIGRP for a new network. The network will be sensitive to congestion and must respond quickly to topology changes. What are two good reasons to choose EIGRP instead of RIP in this case? (Choose two.)

EIGRP uses periodic updates.**EIGRP only updates affected neighbors.EIGRP uses broadcast updates.**EIGRP updates are partial.EIGRP uses the efficient Bellman-Ford algorithm.

12Which two conditions are most likely to cause a routing loop? (Choose two.)

random jitterimplementation of classful addressing**inconsistent routing tables**incorrectly configured static routesa network converging too quickly

13What metric does the RIP routing protocol consider to be infinity?

015**16224255

14What does the RIP holddown timer do?

ensures an invalid route has a metric of 15prevents a router from sending any updates after it has introduced a routing loop into the networkensures every new route is valid before sending an update**instructs routers to ignore updates, for a specified time or event, about possible inaccessible routes

15

Refer to the exhibit. What path will packets from the 192.168.1.0/24 network travel to reach the 10.0.0.0/8 network if RIP is the active routing protocol?

The path will be router A -> router B -> router C -> router E.**The path will be router A -> router D -> router ERouter A will load balance between the router A -> router D -> router E and router A -> router B -> router C -> router E pathPackets will alternate paths depending on the order they arrive at router A.

16Three routers running a distance-vector routing protocol lost all power, including the battery backups. When the routers reload, what will happen?

They will share all routes saved in NVRAM prior to the power loss with their directly connected neighbors.They will multicast hello packets to all other routers in the network to establish neighbor adjacencie**They will send updates that include only directly connected routes to their directly connected neighborThey will broadcast their full routing table to all routers in the networ

17What is a routing loop?

a packet bouncing back and forth between two loopback interfaces on a routea condition where a return path from a destination is different from the outbound path forming a "loop**a condition where a packet is constantly transmitted within a series of routers without ever reaching its intended destinatiothe distribution of routes from one routing protocol into another

18Which statement is true regarding cisco’s RIP_JITTER variable?

It prevents the synchronization of routing updates by buffering the updates as they leave the router interface**It prevents the synchronization of routing updates by subtracting a random length of time ranging from 0% to 15% of the specified interval time from the next routing updateIt prevents the synchronization of routing updates by causing the router to skip every other scheduled update timIt prevents the synchronization of routing updates by forcing the router to listen when its time for other updates on the lines before sending it

19Which three routing protocols are distance vector routing protocols? (Choose three).

**RIPv**EIGROSPIS-I**RIPv

20Which of the following can exist in a distance vector network that has not converged? (Choose three).

**routing loops**inconsistent traffic forwarding

no traffic forwarding until system converges**inconsistent routing table entriesrouting table updates sent to wrong destinations

21What is the purpose of the TTL field in the IP header?

used to mark routes as unreachable in updates sent to other routersprevents regular update messages from reinstating a route that may have gone badprevents a router from advertising a network through the interface from which the update came**limits the time or hops that a packet can traverse through the network before it should be discardeddefines a maximum metric value for each distance vector routing protocol by setting a maximum hop count

Refer to the exhibit. What two pieces of information can be determined from the output that is shown? (Choose two.)The local host is using well-known port numbers to identify the source ports.**A termination request has been sent to 192.135.250.10.**Communication with 64.100.173.42 is using HTTP Secure.The local computer is accepting HTTP requests.192.168.1.101:1042 is performing the three-way handshake with 128.107.229.50:80.

2 After a web browser makes a request to a web server that is listening to the standard port, what will be the source port number in the TCP header of the response from the server?1353**8010241728

3 Which information is found in both the TCP and UDP header information?sequencingflow controlacknowledgments**source and destination

4 Which is an important characteristic of UDP?acknowledgement of data delivery**minimal delays in data deliveryhigh reliability of data deliverysame order data delivery

5

Refer to the exhibit. Host A is using FTP to download a large file from Server 1. During the download process, Server 1 does not receive an acknowledgment from Host A for several bytes of transferred data. What action will Server 1 take as a result?create a Layer 1 jam signal**reach a timeout and resend the data that needs to be acknowledgedsend a RESET bit to the hostchange the window size in the Layer 4 header

6

Refer to the exhibit. In line 7 of this Wireshark capture, what TCP operation is being performed?**session establishment

segment retransmitdata transfersession disconnect

7

Refer to the exhibit. The initial TCP exchange of data between two hosts is shown in the exhibit. Assuming an initial sequence number of 0, what sequence number will be included in Acknowledgment 2 if Segment 6 is lost?2361850**34313475

8 Why is flow control used for TCP data transfer?to synchronize equipment speed for sent datato synchronize and order sequence numbers so data is sent in complete numerical order**to prevent the receiver from being overwhelmed by incoming datato synchronize window size on the serverto simplify data transfer to multiple hosts

9 During a TCP communication session, if the packets arrive to the destination out of order, what will happen to the original message?The packets will not be delivered.The packets will be retransmitted from the source.**The packets will be delivered and reassembled at the destination.The packets will be delivered and not reassembled at the destination.

10 With TCP/IP data encapsulation, which range of port numbers identifies all well-known applications?0 to 255256 to 1022**0 to 10231024 to 204749153 to 65535

11 Which transport layer protocol provides low overhead and would be used for applications which do not require

reliable data delivery?TCPIP**UDPHTTPDNS

12 What are two features of the User Datagram Protocol (UDP)? (Choose two.)flow control**low overhead**connectionlessconnection-orientedsequence and acknowledgements

13 What mechanism is used by TCP to provide flow control as segments travel from source to destination?sequence numberssession establishment**window sizeacknowledgments

14 What is dynamically selected by the source host when forwarding data?destination logical addresssource physical addressdefault gateway address**source port

15 Why are port numbers included in the TCP header of a segment?to indicate the correct router interface that should be used to forward a segmentto identify which switch ports should receive or forward the segmentto determine which Layer 3 protocol should be used to encapsulate the data**to enable a receiving host to forward the data to the appropriate applicationto allow the receiving host to assemble the packet in the proper order

16 Which two options represent Layer 4 addressing? (Choose two.)identifies the destination networkidentifies source and destination hosts**identifies the communicating applications**identifies multiple conversations between the hostsidentifies the devices communicating over the local media

17 Which three features allow TCP to reliably and accurately track the transmission of data from source to destination?encapsulation**flow controlconnectionless services**session establishment**numbering and sequencingbest effort delivery

18 Which OSI model layer is responsible for regulating the flow of information from source to destination, reliably and accurately?applicationpresentationsession**transportnetwork

19

Based on the transport layer header shown in the diagram, which of the following statements describe the established session? (Choose two.)This is a UDP header.**This contains a Telnet request.This contains a TFTP data transfer.The return packet from this remote host will have an Acknowledgement Number of 43693.**This is a TCP header.

20 Which event occurs during the transport layer three-way handshake?The two applications exchange data.**TCP initializes the sequence numbers for the sessions.UDP establishes the maximum number of bytes to be sent.The server acknowledges the bytes of data received from the client.

21

Refer to the exhibit. Host1 is in the process of setting up a TCP session with Host2. Host1 has sent a SYN message to begin session establishment. What happens next?

Host1 sends a segment with the ACK flag = 0, SYN flag = 0 to Host2.Host1 sends a segment with the ACK flag = 1, SYN flag = 0 to Host2.Host1 sends a segment with the ACK flag = 1, SYN flag = 1 to Host2.

Host2 sends a segment with the ACK flag = 0, SYN flag = 1 to Host1.Host2 sends a segment with the ACK flag = 1, SYN flag = 0 to Host1.**Host2 sends a segment with the ACK flag = 1, SYN flag = 1 to Host1.

_______

CCNA1 Chapter 4

1. Based on the transport layer header shown in the diagram, which of the following statements describe the established session? (Choose two.)

This contains a Telnet request.

This is a TCP header.

2. With TCP/IP data encapsulation, which range of port numbers identifies all well-known applications?

0 to 1023

3. Why are port numbers included in the TCP header of a segment?

to enable a receiving host to forward the data to the appropriate application

4. Which OSI model layer is responsible for regulating the flow of information from source to destination, reliably and accurately?

transport

5. Refer to the exhibit. Host A is using FTP to download a large file from Server 1. During

the download process, Server 1 does notreceive an acknowledgment from Host A for several bytes of transferred data. What action will Server 1 take as a result?

reach a timeout and resend the data that needs to be acknowledged

6. Why is flow control used for TCP data transfer?

to prevent the receiver from being overwhelmed by incoming data

7. Which two options represent Layer 4 addressing? (Choose two.)

identifies the communicating applications

identifies multiple conversations between the hosts

8. Refer to the exhibit. In line 7 of this Wireshark capture, what TCP operation is being performed?

session establishment

9. Refer to the exhibit. What two pieces of information can be determined from the output that is shown? (Choose two.)

A termination request has been sent to 192.135.250.10.

Communication with 64.100.173.42 is using HTTP Secure.

10. Refer to the exhibit. The initial TCP exchange of data between two hosts is shown in the exhibit.Assuming an initial sequence number of 0, what sequence number will be included in Acknowledgment 2 if Segment 6 is lost?

3431

11. What is dynamically selected by the source host when forwarding data?

source port

12. What are two features of the User Datagram Protocol (UDP)? (Choose two.)

low overhead

connectionless

13. What mechanism is used by TCP to provide flow control as segments travel from source to destination?

window size

14. Which transport layer protocol provides low overhead and would be used for applications which do not require reliable data delivery?

UDP

15. Which information is found in both the TCP and UDP header information?

source and destination

16. Which three features allow TCP to reliably and accurately track the transmission of data from source to destination? (Choose three)

flow control

session establishment

numbering and sequencing

17. During a TCP communication session, if the packets arrive to the destination out of order, what will happen to the original message?

The packets will be delivered and reassembled at the destination.

18. Which is an important characteristic of UDP?

minimal delays in data delivery

19. After a web browser makes a request to a web server that is listening to the standard port,what will be the source port number in the TCP header of the response from the server?

80

20. Which event occurs during the transport layer three-way handshake?

TCP initializes the sequence numbers for the sessions.