JAN2012 - Chapter 1 CCNA Exploration 4.0 EWAN Answer and Question

1. Which statement is true about the differences between a WAN and a LAN?
WANs generally support higher bandwidth than LANs support.
A WAN link typically traverses shorter geographic distances than a LAN link traverses.
A WAN often relies on the services of carriers, such as telephone or cable companies, but a LAN does not.
All WAN implementations generally use the same Layer 2 protocol but there are many accepted LAN Layer 2 protocols in use.

2. A U.S. company requires a WAN connection used only to transfer sales data from individual stores to the home office. All transfers will occur after business hours. The required bandwidth for this connection is estimated to be less than 38 kbps. Which type of connection requires the least investment for this company?
ATM
ISDN
analog dialup
T1 Leased Line

3. What are two advantages of an analog PSTN WAN connection? (Choose two.)
low cost
availability
traffic encryption
available bandwidth
support for voice and video

4. Which WAN technology uses a fixed payload of 48 bytes and is transported across both switched and permanent virtual circuits?
ATM
ISDN
Frame Relay
metro Ethernet

5. Which three WAN devices can be found in the cloud? (Choose three.)
ATM switches
core routers
CSU/DSU
Ethernet switches
Frame Relay switches
repeaters

6. Which term describes a device that will put data on the local loop?
DLCI
DTE
DCE
BRI
PRI

7. What is an advantage of packet-switched technology over circuit-switched technology?
Packet-switched networks are less susceptible to jitter than circuit-switched networks are.
Packet-switched networks can efficiently use multiple routes inside a service provider network.
Packet-switched networks do not require an expensive permanent connection to each endpoint.
Packet-switched networks usually experience lower latency than circuit-switched networks experience.

8. Which statement is true about data connectivity between a customer and a service provider?
Normally the CSU/DSU is the designated demarcation point for the service provider but not the customer.
The segment between the demarcation point and the central office is known as the “last mile.”
The local loop is the segment between the CSU/DSU and the serial port on a router.
Putting data on the local loop is the responsibility of the DTE.

9. A company needs a WAN connection that is capable of transferring voice, video, and data at a minimum data rate of 155 Mbps. Which WAN connection is the best choice?
X.25
DSL
ATM
ISDN BRI
ISDN PRI

10. Which statement is true of the functionality of the layers in the hierarchical network model?
The purpose of the access layer is to provide very high bandwidth communications between network devices.
Most security screening to prevent unauthorized entry to the network happens at the core layer.
Untrusted external connections are segmented from the rest of the network at all three levels.
The distribution layer aggregates WAN connections at the edge of the campus.

11. Why is the call setup time of a circuit-switched WAN implementation considered a drawback?
Routing protocols are incompatible with this function.
It restricts the communication sent to voice traffic only.
A telephone must be used to initially start transferring data.
Data cannot be transferred until a circuit has been established.

12. For digital lines, which device is used to establish the communications link between the customer equipment and the local loop?
CSU/DSU
Frame Relay switch
ISDN switch
modem
PBX switch

13. Which packet-switched WAN technology offers high-bandwidth connectivity capable of managing data, voice, and video all on the same infrastructure?
Time Division Multiplexing (TDM)
metro Ethernet
Integrated Services Digital Network (ISDN)
Public Switched Telephone Network (PSTN)

14. Which networking device is typically used to concentrate the dial-in and dial-out traffic of multiple users to and from a network?
core router
access server
Frame Relay switch
ATM switch

15. Which two devices are commonly used as data communications equipment? (Choose two.)
modem
router
CSU/DSU
ISDN switch
Ethernet switch

16. Which two features are identified with Frame Relay connections? (Choose two.)
53-byte cells
DLCI
DSLAM
PVC
SPID

17. Which statement about WAN protocols is correct?
ATM differs from other WAN protocols in that it uses variably sized packets.
Most WAN protocols use HDLC or a variant of HDLC as a framing mechanism.
The frame header consists of the frame check sequence and cyclic redundancy check.
ISDN differs from Frame Relay, HDLC, and ATM in that it is packet-switched rather than circuit-switched technology.

18. Which switching type will allow the communication devices in the provider network to be shared and only allocated to an individual subscriber during data transfer?
circuit-switched
dedicated switched lines
frame-switched
packet-switched

19. What can cause a reduction in available bandwidth on a cable broadband connection?
smaller cells
number of subscribers
committed information rate
distance from the central office of the provider

20. What three terms are associated with ISDN PRI? (Choose three.)
cell
DLCI
circuit switching
packet switching
data bearer channels
time-division multiplexing

21. At which two layers of the OSI model does a WAN operate? (Choose two.)
Physical Layer
Data Link Layer
Network Layer
Transport Layer
Presentation Layer
Application Layer

22. What type of connectivity is established when VPNs are used from the remote site to the private network?
PVCs
DLCIs
tunnels
dedicated Layer 2 links

Update : Links

UCEN 3133 Advanced Computer Networks - Tutorial 4 - Year 2012

Tutorial 4 – QOS and RSVP

1. List and briefly describe the activities that a router or switch is likely to engage in to provide a certain QOS guarantee in a network.

     (i)            Policing: verifying that incoming traffic conforms to its agreed specification

   (ii)            Admission control: checking to see if there are enough resources to meet a request for QoS

 (iii)            Classification: recognizing those packets that need particular levels of QoS 

 (iv)            Queuing and scheduling: making decisions about when packets are transmitted and which packets are dropped that are consistent with the QoS guarantees

2. What is the primary difference between IntServ and DiffServ approaches to allocating resources for QOS purposes ? Which approach scales better for a large IP network and why ?

IntServ enables end-to-end QoS guarantees for a single flow (microflow) from one sender to one or more receivers through a signalling protocol like RSVP

DiffServ a coarse-grained model groups traffic of many different flows into several small classes and provides QOS guarantees on a per-class basis

DiffServ scales better. In a large IP network, the number of microflows is very large and to keep QOS and state information about each one provides a heavy burden on the routers in the network, making it difficult to scale. Grouping flows into classes allows easier management of QOS information.

3. In what way does the deficit round robin (DRR) approach provide for a more fairer QOS allocation of transmission resources on a router as compared to the weighted round robin approach ? Briefly explain how it works.

It computes weights allocated to different flows in terms of total bytes rather than number of packets. This is fairer QOS allocation because IP packets vary in size

DRR allocates a number of bytes to each flow. When a flow is selected, DRR transmits as many packets as possible without exceeding the allotted number of bytes.

The remainder (i.e. the difference between the number of bytes that was allocated and the size of the packets actually sent) becomes a deficit which is added to the amount that will be sent in the next round

4. Explain briefly how RSVP works with reference to the PATH and RESV messages.

     (i)            PATH messages travel from a sender to one or more receivers (explicitly designed to support multicast)  and include TSpecs and classification information provided by the sender.

   (ii)            When a receiver gets a PATH message, it can send a RESV message back toward the sender. The RESV message identifies the session for which the reservation is to be made and indicates the level of QoS required by this receiver.

 (iii)            Messages are intercepted by every router along the path, so that resource allocation can take place at all the necessary hops.

 (iv)            Each router must agree to reserve the resources the request specifies. Reservation is unidirectional for a single flow direction

5. Three clients are receiving shared multicast video traffic flow across a MPLS network from a media server. The routes from these different client converge on a router that the server is directly connected to. All 3 clients make a QOS reservation requests for a delay latency of 30ms, 15 ms and 10 ms respectively to this router.

     (i)            How would RSVP handle these requests in the router ?

   (ii)            How does RSVP ensure that these reservation requests are propagated correctly across the MPLS network to this router at the transmitting end ?

i) These requests are merged into a single reservation request for the common flow, to which the router will select the smallest latency of 10ms

ii) When a path message in RSVP is sent to a client, each router at each hop inserts its own IP address as the message’s last hop. Each router can look at the last hop field to learn where the flow came from. Should it later receive a reservation request for this flow, this last hop information tells it where to send the reservation request next.

6. Explain briefly what the term soft state means within the context of RSVP. Consider an ongoing video conference involving 2 clients receiving multicast traffic  from a central server. A new client wishes to join this multicast group. Outline the series of steps that it will undergo to achieve this, and show how soft state helps in this registration process.

Soft state means that PATH and RESV messages in RSVP must be sent periodically to refresh a reservation. If they are not sent for some interval (the time-out period), then the reservation is automatically torn down

1. The client sends an IGMP group membership report message to join this multicast group.
2. The local router receives this message and to update the rest of the network, the router builds an OSPF link state advertisement and floods it through the network.   Once all routers are updated, multicast traffic begins to flow to the new client.
3. Path messages for the flow can reach it as well, and soft state assures that a periodic path message from the sender will eventually reach the new client.
4. With this path message in hand, the client can identify the flow and place its own reservations.

7.  How does label distribution in MPLS assist in the creation of a RSVP reserved flows ? Describe briefly the steps involved in this process which lead to the creation of a label switched path (LSP).

Labels are bound between flows that have RSVP reservations (through the use of a FEC) and then distributed through the MPLS network.

When an LSR wants to send a RESV message for a new RSVP flow:

     (i)            It allocates a label from its pool of free labels

   (ii)            Creates an entry in its LFIB with the incoming label set to the allocated label

 (iii)            Sends out the RESV message containing this label to the upstream LSR.

 (iv)            Upon receipt of a RESV that contains this label, an LSR populates its LFIB with this label as the outgoing label

   (v)            It then allocates a new label to use as the incoming label and inserts that in the RESV message before sending it upstream.

 (vi)            As RESV messages propagate upstream, an LSP is established along the path.

8. What is meant by Per Hop Behaviour (PHB) in the context of the DiffServ approach to QOS allocation and how is it indicated ? Briefly describe the 3 main types of PHBs

DiffServ allows each node along the path to define the service that a given class will receive and this can vary from node to node along a given path, therefore DiffServ does not provide QOS end-to-end guarantees. Each of the standard PHBs is indicated by a recommended DSCP value, and each router has a table that maps the DSCP found in a packet to the PHB that will determine how that packet is treated

Default - No special treatment, equivalent to best effort.

Expedited forwarding (EF) - Packets marked EF should be forwarded with minimal delay and experience low loss.

Assured forwarding (AF) - Packets go into different priority queues where they have different drop preferences if congestion occurs

9. Briefly describe the standard approach towards congestion avoidance in TCP and state two disadvantages with this approach.   Explain how Explicit Congestion Notification (ECN) overcomes these disadvantages.

Congestion avoidance in TCP assumes that packet losses in the network are an indication of congestion, and reduce their sending rates when they experience packet loss.

Disadvantages:

     (i)            For real time applications, the lost packet will need to be transmitted and its late arrival will cause degradation

   (ii)            A lost packet consumes resources up to the point it is lost, it would be preferable not to send the packet at all if it is just going to be thrown away

Router sets “congestion experienced” (CE) bit in packet header when it detects congestion, and then forward the packets rather than dropping it. The router must have some form of queue management to actively monitor congestion. When a packet with the CE bit arrives at its destination, the receiver must send a signal back to the sender that will cause the sender to reduce its sending rate.

10. A multimedia network that provides QOS guarantees uses a leaky bucket policer in one of its routers to ensure that the incoming packet traffic does not exceed the TSpec specification agreed upon during an initial session of Integrated Services (IntServ). The following are the features of this policer:

·         The token buffer can hold at most three (3) tokens, and is initially filled with two (2) tokens at time slot t = 0.

·         New tokens arrive into the bucket at a rate of two (2) tokens per time slot. Packets arrive at the beginning of a time slot and enter the packet queue, where they are processed and transferred to the output link in a First In First Out (FIFO) manner.

·         The size of the packet queue is four  (i.e. it can queue a maximum of 4 packets at any given time slot); any extra arriving packets are dropped.

·         Packets that obtain available tokens in a given time slot go together on the same time slot in the output link.             

Time slot	Incoming Packets
0	A B C D
1	E F
2	G
3	-
4	-
5	H I J K
6	L M N O
7	P Q
8	-
9	R S T

The table shows incoming packets from the network into the router with the policer, from time slot t = 0 to time slot t = 9. Based on this information, construct a new table with columns showing the packets in queue, tokens in bucket and packets on output link from time slot t = 0 to t = 9.                                            

Time slot	Packets in queue	Tokens in bucket	Packets at output
0	A B C D	2	A B
1	C D E F	2	C D
2	E F G	2	E F
3	G	2	G
4	-	3	-
5	H I J K	3	H I J
6	K L M N	2	K L
7	M N P Q	2	M N
8	P Q	2	P Q
9	R S T	2	R S

Year 2010 EWAN Final Exam : Accessing the WAN (Version 4.0)

1
Which encapsulation protocol when deployed on a Cisco router over a serial interface is only compatible with another Cisco router?

PPP
SLIP
HDLC
Frame Relay

2
What is a characteristic feature of a worm?

exploits a known vulnerability
attaches to executable programs
masquerades as a legitmate program
lies dormant until triggered by an event, time, or date

3
An administrator is configuring a dual stack router with IPv6 and IPv4 using RIPng. The administrator receives an error message when trying to enter the IPv4 routes into RIPng. What is the cause of the problem?

When IPv4 and IPv6 are configured on the same interface, all IPv4 addresses are over-written in favor of the newer technology.
Incorrect IPv4 addresses are entered on the router interfaces.
RIPng is incompatible with dual-stack technology.
IPv4 is incompatible with RIPng.

4
Which statement accurately describes a characteristic of a security policy?

It creates a basis for legal action if necessary.
It should not need altering once it is implemented.
It provides step-by-step procedures to harden routers and other network devices.
It is kept private from users to prevent the possibility of circumvention of security measures.

5
Which characteristic of VPN technology prevents the contents of data communications from being read by unauthorized parties?

QoS
latency
reliability
confidentiality

6
Refer to the exhibit. A network administrator is configuring Frame Relay on router HQ. It is desired that each Frame Relay PVC between the routers be in a separate subnet. Which two commands on HQ will accomplish this task for the connection to R1? (Choose two.)

HQ(config)# interface S0/0/0
HQ(config)# interface S0/0/0.1 multipoint
HQ(config)# interface S0/0/0.1 point-to-point
HQ(config-subif)# frame-relay interface dlci 103
HQ(config-subif)# frame-relay interface dlci 301
HQ(config-if)# frame-relay map ip 172.16.1.1 255.255.255.0 301 broadcast

7
Refer to the exhibit. Router1 and Router2 are directly connected over a point-to-point serial link. Router1 initiates a PPP session with Router2. Which statement is true based on the configuration?

The password is sent in clear text.
The routers are unable to authenticate.
The username and password are sent encrypted.
A hash value of the username and password are sent.

8
A technician has been asked to run Cisco SDM one-step lockdown on the router of a customer. What will be the result of this process?

Traffic is only forwarded from SDM-trusted Cisco routers.
Security testing is performed and the results are saved as a text file stored in NVRAM.
The router is tested for potential security problems and any necessary changes are made.
All traffic entering the router is quarantined and checked for viruses before being forwarded.

9
Which two statements are true about creating and applying access lists? (Choose two.)

There is an implicit deny at the end of all access lists.
One access list per port, per protocol, per direction is permitted.
Access list entries should filter in the order from general to specific.
The term "inbound" refers to traffic that enters the network from the router interface where the ACL is applied.
Standard ACLs should be applied closest to the source while extended ACLs should be applied closest to the destination.

10
Refer to the exhibit. Company ABC expanded its business and recently opened a new branch office in another country. IPv6 addresses have been used for the company network. The data servers Server1 and Server2 run applications which require end-to-end functionality, with unmodified packets that are forwarded from the source to the destination. The edge routers R1 and R2 support dual stack configuration. What solution should be deployed at the edge of the company network in order to successfully interconnect both offices?

a new WAN service supporting only IPv6
NAT overload to map inside IPv6 addresses to outside IPv4 address
a manually configured IPv6 tunnel between the edge routers R1 and R2
static NAT to map inside IPv6 addresses of the servers to an outside IPv4 address and dynamic NAT for the rest of the inside IPv6 addresses

11
A company uses a PVC with a committed information rate (CIR) of 128 kb/s and a committed burst information rate (CBIR) of 64 kb/s. The link is used to periodically send updates at a rate of 144 kb/s. What will happen to the update traffic?

The traffic will be sent, but the company will be charged a penalty.

The traffic will be sent using the additional CBIR and will be guaranteed delivery.

The traffic will be dropped at the CO for exceeding the committed information rate.

The traffic will be sent, but the burst traffic will be marked for discard if congestion is encountered.

12
Refer to the exhibit. All devices are configured as shown in the exhibit. PC1 is unable to ping the default gateway. What is the cause of the problem?

The default gateway is in the wrong subnet.
STP has blocked the port that PC1 is connected to.
Port Fa0/2 on S2 is assigned to the wrong VLAN.
S2 has the wrong IP address assigned to the VLAN30 interface.

13
A system administrator must provide Internet connectivity for ten hosts in a small remote office. The ISP has assigned two public IP addresses to this remote office. How can the system administrator configure the router to provide Internet access to all ten users at the same time?

Configure DHCP and static NAT.
Configure dynamic NAT for ten users.
Configure static NAT for all ten users.
Configure dynamic NAT with overload.


14
Refer to the exhibit. From the output of the show interfaces and ping commands, at which layer of the OSI model is a fault indicated?

application
transport
network
data link
physical

15
Refer to the exhibit. Results of the show vlan and show vtp status commands for switches S1 and S2 are displayed in the exhibit. VLAN 11 was created on S1. Why is VLAN 11 missing from S2?

There is a Layer 2 loop.

The VTP domain names do not match.

Only one switch can be in server mode.

S2 has a higher spanning-tree priority for VLAN 11 than S1 does.

16
Refer to the exhibit. What is the effect of the extended ACL when applied inbound on the S0/0/0 interface on R2?

All IP traffic will be permitted during the specified days and time range.

Both IP and Telnet traffic will be permitted during the specified days and time range.

Only Telnet traffic destined for 172.16.10.0/24 will be permitted during the specified days and time range.

Telnet traffic will be permitted only during the specified days and time range. All other network traffic will be permitted any time.


17
Which three guidelines would help contribute to creating a strong password policy? (Choose three.)

Once a good password is created, do not change it.
Deliberately misspell words when creating passwords.
Create passwords that are at least 8 characters in length.
Use combinations of upper case, lower case, and special characters.
Write passwords in locations that can be easily retrieved to avoid being locked out.
Use long words found in the dictionary to make passwords that are easy to remember.

18
Refer to the exhibit. How is the TCP/IP configuration information specified by the default-router and dns-server commands made available?

The TCP/IP information is forwarded to a 10.0.1.3 to be supplied to DHCP clients.

The TCP/IP information is used by DNS clients to forward all data to the default gateway on R1 of 10.0.1.3.

The TCP/IP information is supplied to any DHCP client on the network connected to the FastEthernet 0/0 interface of R1.

The TCP/IP information is applied to each packet that enters R1 through the FastEthernet 0/0 interface that are hosts on the 10.0.1.0 /24 network except packets from addresses 10.0.1.2, 10.0.1.16, and 10.0.1.254.


19
Which variable is permitted or denied by a standard access control list?

protocol type
source IP address
source MAC address
destination IP address
destination MAC address

20
When configuring a Frame Relay connection, what is the purpose of Inverse ARP?

to assign a DLCI to a remote peer
to disable peer requests from determining local Layer 3 addresses
to negotiate LMI encapsulations between local and remote Frame Relay peers
to create a mapping of DLCI to Layer 3 addresses that belong to remote peers

OCT 2009 CCNA Exploration 4.0 EWAN Chapter 8 - Accessing the WAN

 updated: OCT 2009 by bluefiz 100%  

1. Which two pieces of information are typically found on a logical network diagram? (Choose two.)
- cable types
- connector types
- interface identifiers
- DLCI for virtual circuits
- operating system versions

2. Excessive broadcasts are generally a symptom of a problem at which layer?
- physical
- data link
- network
- transport

3. What is one example of a physical layer problem?
- incorrect encapsulation
- incorrect STP configuration
- incorrect ARP mapping
- incorrect clock rate

4. Which two components should be taken into consideration when establishing a network baseline? (Choose two.)
- information about the network design
- IP addressing allocation on the network
- requirements about the service provider setup
- requirements for access control lists to regulate traffic
- expected performance under normal operating conditions

5. Refer to the exhibit. Which two steps should be taken during the process of creating network documentation? (Choose two.)


- Record the information about the devices discovered in the Campus network only.
- Record the information about the devices discovered in the entire network, including the remote locations.
- Transfer any information about the devices from the network configuration table that corresponds to a component of the topology diagram.
- Transfer only the Layer 2 and Layer 3 information about the devices from the network configuration table that corresponds to a component of the topology diagram.
- Transfer the recorded information about the devices from the network configuration table gathered during peak network utilization that corresponds to a component of the topology diagram.

6. Which two statements are true concerning logical networking models? (Choose two.)
- TCP/IP splits the lowest layer of the OSI model into two separate layers.
- The top layer of the TCP/IP model combines the functions of the top three OSI layers.
- Troubleshooting with the TCP/IP model requires different techniques than with the OSI model.
- The network access layer is responsible for exchanging packets between devices on a TCP/IP network.
- The Internet layer provides communication between applications, such as FTP, HTTP, and SMTP on separate hosts.
- The TCP/IP network access layer corresponds to the OSI physical and data link layers.

7. Clients across the company are reporting poor performance across all corporate applications running in the data center. Internet access and applications running across the corporate WAN are performing normally. The network administrator observes a continual broadcast of random meaningless traffic (jabber) on the application server LAN in the data center on a protocol analyzer. How should the administrator start troubleshooting?
- The jabber in the data center indicates a local physical layer problem. Use the protocol analyzer to determine the source of the jabber, and then check for a recent NIC driver update or bad cabling.
- Because all clients are experiencing application problems, the administrator should use a top-down approach with the application servers in the data center.
- The scope of the problem indicates a likely routing or spanning-tree problem. Begin by checking routing tables, and follow up using appropriate STP show commands to find a loop if routing is working normally.
- Poll the staff to determine if any recent changes have been made. Back out all the changes one by one until the error condition is fixed.

8. Which troubleshooting approach is suggested for dealing with a complex problem that is suspected of being caused by faulty network cabling?
- bottom up
- top down
- divide and conquer
- middle out

9. A technician has been asked to make several changes to the configuration and topology of a network and then determine the outcome of the changes. What tool can be used to determine the overall effect caused by the changes?
- baselining tool
- knowledge base
- protocol analyzer
- cable tester

10. A technician has been asked to troubleshoot an existing switched network but is unable to locate documentation for the VLAN configuration. Which troubleshooting tool allows the technician to map and discover VLAN and port assignments?
- cable analyzer
- network analyzer
- protocol analyzer
- knowledge base

11. Refer to the exhibit. Users on the Internal LAN are unable to connect to the www server. The network administrator pings the server and verifies that NAT is functioning correctly. Which OSI layer should the administrator begin to troubleshoot next?


- physical
- data link
- network
- application

12. When gathering symptoms for troubleshooting a network problem, which step could result in getting an external administrator involved in the process?
- narrowing the scope
- gathering symptoms from suspect devices - analyzing existing symptoms
- determining ownership

13. Refer to the exhibit. Which three pieces of information can be determined by analyzing the output shown? (Choose three.)
- A carrier detect signal is present.
- Keepalives are being received successfully.
- Default encapsulation is used on this serial link.
- Packets passing this interface cannot exceed 1 KB in size.
- The reliability of this link is very low.
- The LCP negotiation phase is complete.

14. Refer to the exhibit. Users at Branch B are reporting trouble accessing a corporate website running on a server that is located at HQ. HQ and Branch A users can access the website. R3 is able to ping 10.10.10.1 successfully but not 10.10.10.2. The users at Branch B can access servers at Branch A. Which two statements are true aboutthe troubleshooting efforts? (Choose two.)

- The web server should be tested for an application layer problem.
- Frame Relay at R3 and R2 should be tested to narrow the scope of the problem.
- The fact that users at Branch A are working normally proves that there is no problem at R2.
- An ACL entry error could cause the failure at Layer 4 in either R3 or R2.
- The successful ping from R3 to R1 proves that the WAN is functioning normally. Therefore, the problem has to be in the upper layers.

15. Users are complaining of very long wait times to access resources on the network. The show interface command reveals collision counts far above the network baseline. At which OSI layer should the administrator begin troubleshooting?
- application
- transport
- network
- data link
- physical

16. Encapsulation errors from mismatched WAN protocols on a serial link between two routers indicate a problem at which OSI layer?
- physical
- data link
- network
- transport

17. What combination of IP address and wildcard mask should be used to specify only the last 8 addresses in the subnet 192.168.3.32/28?
- 192.168.3.32 0.0.0.7
- 192.168.3.32 0.0.0.15
- 192.168.3.40 0.0.0.7
- 192.168.3.40 0.0.0.15

18. A network administrator has received complaints that users on a local LAN can retrieve e-mail from a remote e-mail server but are unable to open web pages on the same server. Services at which two layers of the OSI model should be investigated during the troubleshooting process? (Choose two.)
- physical layer
- data link layer
- network layer
- transport layer
- application layer

19. Information about which OSI layers of connected Cisco devices can be verified with the show cdp neighbors command?
- All layers
- Layer 1, Layer 2, and Layer 3
- Layer 1, Layer 2, Layer 3, and Layer 4
- Layer 6 and Layer 7

20. Which three approaches should be used when attempting to gather data from users for troubleshooting? (Choose three.)
- Determine fault.
- Get to know the user to build trust.
- Obtain information by asking simple pertinent questions.
- Impress the user with use of technical language and skills.
- Determine if the problem is related to time or a specific event.
- Determine if the user can re-create the problem or events leading to the problem.

updated: OCT 2009 by bluefiz 100%
For image version, please send your request to lovestoryhouse@gmail.com. thx.
Disclaimer: This questionnaires are just for revision purpose! 

OCT 2009 CCNA Exploration 4.0 EWAN Chapter 7 - Accessing the WAN

  updated: OCT 2009 by bluefiz 100%

1. Refer to the exhibit. A network technician determines DHCP clients are not working properly. The clients are receiving IP configuration information from a DHCP server configured on the router but cannot access the Internet. From the output in the graphic, what is the most likely problem?

- The DHCP server service is not enabled.
- The inside interface for DCHP is not defined.
- The DHCP pool is not bound to the interface.
- The pool does not have a default router defined for the clients.
- All the host addresses have been excluded from the DHCP pool.

2. Refer to the exhibit. On the basis of the configuration shown, how should the pool of the excluded addresses be assigned to key hosts on the network, such as router interfaces, printers, and servers?

- The addresses are statically assigned by the network administrator.
- The DHCP server dynamically assigns the addresses.
- The addresses must be listed under the DHCP pool of addresses before they are available for static assignment.
- The addresses must be listed under the DHCP pool of addresses before they are available for dynamic assignment.

3. Refer to the exhibit. According to the output, how many addresses have been successfully assigned by this DHCP server?


- 1
- 6
- 7
- 8
-9

4. What are two benefits of NAT? (Choose two.)
- It saves public IP addresses.
- It adds a degree of privacy and security to a network.
- It increases routing performance.
- It makes troubleshooting routing issues easier.
- It makes tunneling with IPsec less complicated.

5. What is true regarding the differences between NAT and PAT?
- PAT uses the word "overload" at the end of the access-list statement to share a single registered address.
- Static NAT allows an unregistered address to map to multiple registered addresses.
- Dynamic NAT allows hosts to receive the same global address each time external access is required.
- PAT uses unique source port numbers to distinguish between translations.

6. What type of NAT should a network administrator use to ensure that a web server on the inside network is always available to the outside network?
- NAT overload
- static NAT
- dynamic NAT
- PAT

7. Refer to the exhibit. Which address or addresses represent the inside global address?


- 10.1.1.2
- 192.168.0.100
- 209.165.20.25
- any address in the 10.1.1.0 network

8. Refer to the exhibit. Which two statements about the configuration are true? (Choose two.)

- Traffic from the 10.1.1.0 network will be translated.
- Traffic from the 209.165.200.0 network will be translated.
- Permitted traffic gets translated to a single inside global IP address.
- A pool of inside global IP addresses from the 10.1.1.0 network will be used for translation.
- External users from the 209.165.200.0 network can reach private addresses on the 10.1.1.0 and 10.1.2.0 networks.

9. Refer to the exhibit. What is the purpose of the command marked with an arrow shown in the partial configuration output of a Cisco broadband router?


- defines which addresses can be translated
- defines which addresses are allowed into the router
- defines which addresses are assigned to a NAT pool
- defines which addresses are allowed out of the router

10. A technician has been told by a supervisor to always clear any dynamic translations before attempting to troubleshoot a failed NAT connection. Why has the supervisor issued these instructions?
- The supervisor wants to clear any confidential information that may be seen by the technician.
- Because entries can be cached for long periods of time, the supervisor wants to prevent decisions being made based on old data.
- The translation table may be full and is unable to make new translations until space is available.
- Clearing the translations causes the starting configuration to be reread and may correct translation problems that have occurred.

11. Refer to the exhibit. Traffic exiting R1 is failing translation. What part of the configuration is most likely incorrect?

- ip nat pool statement
- access-list statement
- ip nat inside is on the wrong interface
- interface s0/0/2 should be a private IP address 
 

12. Refer to the exhibit. A technician used SDM to enter the NAT configuration for a Cisco router. Which statement correctly describes the result of the configuration?

- A user on the inside sees web traffic coming from 192.168.1.3 using port 8080.
- The address 172.16.1.1 is translated into an address from the pool beginning with 192.168.1.3.
- A user on the outside network sees a request addressed from 192.168.1.3 using port 80.
- A user on the outside must address traffic to port 8080 to reach the address 172.16.1.1.
 
13. Refer to the exhibit. How many IPv6 broadcast domains exist in this topology?

- 0
- 1
- 2
- 3
- 4

14. A network administrator wants to connect two IPv6 islands. The easiest way is through a public network that uses only IPv4 equipment. What simple solution solves the problem?
- Replace the devices on the public network with devices that support IPv6.
- Configure RIPng on the border routers of each IPv6 island.
- Configure the routers to take advantage of dual-stack technology.
- Use tunneling to encapsulate the IPv6 traffic in the IPv4 protocol.

15. After activating IPv6 routing on a Cisco router and programming IPv6 addresses on multiple interfaces, what is the remaining step to activate RIPng?
- Enter the interface programming mode for each IPv6 interface and enable IPng RIP.
- Enter the ipv6 router rip name command and then use network statements to activate RIPng on the interfaces.
- Enter the router rip command, and then activate RIPng using the version command. RIPng then automatically runs on all IPv6 interfaces.
- Enter the interface programming mode for each IPv6 interface and enable the multicast group FF02::9, and then activate RIPng globally using the ipv6 router rip name command.

16. Refer to the exhibit. The FTP server has an RFC 1918 private address. Users on the Internet need to connect to the FTP server on the Fa0/0 LAN of R1. Which three configurations must be completed on R1? (Choose three.)

- dynamic NAT
- NAT with overloading
- open port 20
- open port 21
- open port 23
- NAT with port forwarding

17. Refer to the exhibit. R1 is performing NAT for the 10.1.1.0/24 network, and R2 is performing NAT for the 192.168.1.2/24 network. What would be valid destination IP address for HostA to put in its IP header when communicating with the web server?



- 10.1.1.1
- 172.30.20.2
- 192.168.1.2
- 255.255.255.255

18. Refer to the exhibit. Which two addresses could be assigned to traffic leaving S0 as a result of the statement ip nat pool Tampa 179.9.8.96 179.9.8.111 netmask 255.255.255.240? (Choose two.)

- 10.0.0.125
- 179.9.8.95
- 179.9.8.98
- 179.9.8.101
- 179.9.8.112

19. Refer to the exhibit. IPv6 address 2006:1::1/64 eui-64 has been configured on the router FastEthernet0/0 interface. Which statement accurately describes the EUI-64 identifier configuration?

- It will randomly generate a 64 bit interface ID.
- It will assign an address from the pool of IPv6 private addresses to the interface.
- It will assign only the registry prefix of the IPv6 Global Unicast address to the interface.
- The configuration will derive the interface portion of the IPv6 address from the MAC address of the interface.

20. How many bits of an IPv6 address are used to identify the interface ID?
- 32
- 48
- 64
- 128

21. Your organization is issued the IPv6 prefix of 2001:0000:130F::/48 by your service provider. With this prefix, how many bits are available for your organization to create subnetworks?
- 8
- 16
- 80
- 128

 updated: OCT 2009 by bluefiz 100%
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