Voice/Data Integration Technologies - Advances in Applications

Advances in Applications

Real cost savings are sufficient for deployment of voice/data integration technologies. However, there are added benefits, which will become more evident in the future. As applications evolve, organizations will gain increased user productivity from the integration of voice and computer applications. Computer telephony integration (CTI) was begun by PBX vendors in the 1980s to integrate computers with PBXs to provide applications such as advanced call center features (for example, "screen pops" for agents).

However, as voice/data integration continues, the line between voice and data applications will continue to blur. For example, Unified Messaging systems are now available that combine voice mail, e-mail, and fax messaging into a single, convenient system. With these advanced systems, users can have e-mail read to them over the phone or can add document attachments to voice mail. At the enterprise level, new applications such as virtual call centers allow call center agents to be distributed anywhere within reach of the data network, while still receiving the full suite of call center functions and features. They can even receive calls over their computers rather than using a traditional telephone instrument, and they can provide "blended contact center" support to answer Web user questions with electronic chat capability and e-mail between voice calls. These capabilities go far beyond simple cost savings and will ultimately make organizations much more effective and profitable.

The strong pressures driving the integration of voice and data networks have resulted in various solutions to the problem, each with its own strengths and weaknesses. Three general approaches exist:

•Voice over ATM

•Voice over Frame Relay

•Voice over IP

There are also mixed solutions, including voice over IP, over Frame Relay, and so on. These are illustrated in Figure 19-1 The figure shows that voice over ATM and voice over Frame Relay are primarily transport mechanisms between PBXs, while voice over IP can connect all the way to the desktop. More details are available later in this chapter.

Figure 19-1 Mixed Solutions Including Voice over IP, Voice over Frame Relay, and so on.

Voice/Data Integration Technologies - Introduction

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Introduction

Voice/data integration is important to network designers of both service providers and enterprise. Service providers are attracted by the lower-cost model—the cost of packet voice is currently estimated to be only 20 to 50 percent of the cost of a traditional circuit-based voice network. Likewise, enterprise network designers are interested in direct cost savings associated with toll-bypass and tandem switching. Both are also interested in so-called "soft savings" associated with reduced maintenance costs and more efficient network control and management. Finally, packet-based voice systems offer access to newly enhanced services such as Unified Messaging and application control. These, in turn, promise to increase the productivity of users and differentiate services.

Integration of voice and data technologies has accelerated rapidly in recent years because of both supply- and demand-side interactions. On the demand side, customers are leveraging investment in network infrastructure to take advantage of integrated applications such as voice applications. On the supply side, vendors have been able to take advantage of breakthroughs in many areas, including standards, technology, and network performance.

Standards

Many standards for interoperability for voice signaling have finally been ratified and matured to the point of reasonable interoperability. This reduces the risk and costs faced by vendors offering components of a voice/data system, and it also reduces the risk to consumers. Standards such as H.323 (approved by the ITU in June 1996), are now evolving through their third and fourth iterations, while products based on initial standards still enjoy strong capabilities and interoperability. The general maturity of standards has in turn generated robust protocol stacks that can be purchased "off the shelf" by vendors, further ensuring interoperability.

Technology

Recent advances in technology have also enabled voice integration with data. For example, new Digital Signal Processor (DSP) technology has allowed analog signals to be processed in the digital domain, which was difficult or impossible only a few years earlier. These powerful new chips offer tremendous processing speeds, allowing voice to be sampled, digitized, and compressed in real time. Further breakthroughs in the technology allow as many as four voice conversations to be managed at the same time on a single chip, with even greater performance in development. These technologies greatly reduce the cost and complexity of developing products and deploying voice over data solutions.

In other areas, the industry has also enjoyed breakthroughs in voice codec (coder/decoder) technology. Previously, it was assumed that voice quality would suffer as bandwidth was decreased in a relatively linear fashion. However, new, sophisticated algorithms employed in new codecs have changed that view. It is now possible to obtain reasonably good-sounding voice at a fraction of the bandwidth once required. More importantly, these new algorithms have been incorporated into the standards to allow interoperability of highly compressed voice.

Network Performance

Finally, data-networking technology has improved to the point that voice can be carried reliably. Over the last few years, growth in voice traffic has been relatively small, while data traffic has grown exponentially. The result is that data traffic is now greater than voice traffic in many networks. In addition, the relative importance of data traffic has grown, as businesses and organizations come to base more business practices and policies on the ubiquity of data networks. This increase in importance of data networks has forced a fundamental change in the way data networks are engineered, built, and managed. Typical "best-effort" data modeling has given way to advanced policy-based networking with managed quality of service to support an even greater range of applications. Voice traffic, as an application on a data network, has benefited greatly from these technologies. For example, support of delay-sensitive SNA traffic over IP networks resulted in breakthroughs in latency management and queuing prioritization, which was then applied to voice traffic.

As stated previously, deployment of new technologies and applications must also be driven by greater demand from users. Breakthroughs in technology don't necessarily result in increased deployment unless they fill a real user need at a reasonable cost. For example, digital audio tape (DAT) technologies never enjoyed widespread use outside the audiophile community because of the high cost and only marginally better perceived performance than analog tapes. Voice/data integration, however, provides users with very real benefits, both now and in the future. Most users of voice/data integration technologies gain in two ways: Packet voice technologies are less expensive, and, in the future, they will offer much greater capabilities compared to today's circuit-based voice systems.

Economic Advantages

It has been estimated that packet voice networking costs only 20 to 30 percent of an equivalent circuit-based voice network. This is true for both carriers (service providers) and enterprise (private) users. Logically, this implies that enterprise users can operate long-distance voice services between facilities at less cost than purchasing long-distance voice services from a carrier, and it's often true. For example, many enterprise users have deployed integrated voice/data technologies to transport voice over data wide-area networks (WANs) between traditional PBXs across different geographical locations. The resulting savings in long-distance toll charges often provide payback in as little as six months (especially if international calls are avoided). Using data systems to carry voice as "virtual tie lines" between switches is also useful to service providers. In fact, many new carriers have started to embrace packet-based voice technologies as their primary network infrastructure strategy going forward.

However, savings associated with packet voice technologies don't stop with simple transport. It is also possible to switch voice calls in the data domain more economically than traditional circuit-based voice switches. For large, multisite enterprises, the savings result from using the data network to act as a "tandem switch" to route voice calls between PBXs on a call-by-call basis. The resulting voice network structure is simpler to administer and uses a robust, nonblocking switching fabric made up of data systems at its core.

IPv6

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One of the newest major standards on the horizon is IPv6. Although IPv6 has not officially become a standard, it is worth some overview. It is very possible that this information will change as we move closer to IPv6 as a standard, so you should use this as a guide into IPv6, not the definitive information.

A number of books are now being published that cover in detail this emerging standard; if you are looking for more details you should refer to these books. All the RFCs available on the Internet have the raw details on how this standard is developing. However, these documents are difficult to interpret at first glance and require some commitment to going through any number of RFCs pertaining to many subjects all related to IPv6 development.

Internet Protocol Version 4 is the most popular protocol in use today (see Chapter 31, "Internet Protocols"), although there are some questions about its capability to serve the Internet community much longer. IPv4 was finished in the 1970s and has started to show its age. The main issue surrounding IPv6 is addressing—or, the lack of addressing—because many experts believe that we are nearly out of the four billion addresses available in IPv4. Although this seems like a very large number of addresses, multiple large blocks are given to government agencies and large organizations. IPv6 could be the solution to many problems, but it is still not fully developed and is not a standard—yet!

Many of the finest developers and engineering minds have been working on IPv6 since the early 1990s. Hundreds of RFCs have been written and have detailed some major areas, including expanded addressing, simplified header format, flow labeling, authentication, and privacy.

Expanded addressing moves us from 32-bit address to a 128-bit addressing method. It also provides newer unicast and broadcasting methods, injects hexadecimal into the IP address, and moves from using "." to using ":" as delimiters. Figure 32-1 shows the IPv6 packet header format.

Figure 32-1 IPv6 Packet Header Format

Description of IPv6 Packet Header

The simplified header is 40 bits long and the format consists of Version, Class, Flow Label, Payload Length, Next Header, Hop Limit, Source Address, Destination Address, Data, and Payload fields.

Hexadecimal "Hex"

At its simplest, hex numbers are base 16. Decimal is base 10, counting from 0 to 9, as we do in decimal, and then adding a column to make 10. Counting in hex goes from 0 to F before adding a column. The characters A through F represent the decimal values of 10 through 15, as illustrated in Figure 32-2.

Figure 32-2 Hex Characters A Through F Represent the Numbers 10 Through 15

Counting in hex goes as follows: 0 1 2 3 4 5 6 7 8 9 A B C D E F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 and up, as far as you want to go.

Addressing Description

Let's look at an example of IPv6 address. The address is an eight-part hex address separated by colons (" :"). Each part n can equal a 16-bit number and is eight parts long, providing a 128-bit address length (16 ¥ 8 = 128),

Addresses are n:n:n:n:n:n:n:n n = 4 digit hexadecimal integer, 16 ¥ 8 = 128 address.

1080:0:0:0:8:800:200C:417A Unicast address

FF01:0:0:0:0:0:0:101 Multicast address

Broadcasting Methods

Included in IPv6 are a number of new broadcasting methods:

•Unicast

•Multicast

•Anycast

Unicast

Unicast is a communication between a single host and a single receiver. Packets sent to
a unicast address are delivered to the interface identified by that address, as seen in
Figure 32-3.

Figure 32-3 Unicast Sends Packets to a Specified Interface

Multicast

Multicast is communication between a single host and multiple receivers. Packets are sent to all interfaces identified by that address, as seen in Figure 32-4.

Figure 32-4 Multicast Sends Packets to a Subnet, and Defined Devices Listen for Multicast Packets

Anycast

Packets sent to an anycast address or list of addresses are delivered to the nearest interface identified by that address. Anycast is a communication between a single sender and a list of addresses, as shown in Figure 32-5.

Figure 32-5 Anycast Sends Packets to Specified Interface List and Can Contain End Nodes and Routers

Summary

Some of the benefits of IPv6 seem obvious: greater addressing space, built-in QoS, and better routing performance and services. However, a number of barriers must be overcome before the implementation of IPv6. The biggest question for most of us will be what the business need is for moving from current IPv4 to IPv6. The killer app has not appeared yet, but it may be closer than we think. The second consideration is the cost—it may not have much to do with hardware replacement cost. All the larger routers have upgradable OSs IOS; the only necessity is the commitment to upgrading IOS. More likely to do with training and support of minor IP devices such as printers and network faxes, they will support the new address space. IPv6 has schemes to support old and new, however, so this may not even be a barrier. The last issue to consider is training: This will need to happen sooner or later because we all need to start thinking about 128-bit addressing based on MAC addresses in HEX. This involves all new ways of addressing and will be an uncomfortable change for many people.

This conclusion may seem negative, but the greater good will overpower all the up-front issues. The issue is not whether you will have to move to IPv6, but when! We all need IPv6; the increased address space is needed for the growth of IP appliances that we are starting to hear about weekly. IP-ready cars are already shipping today. This requires mobility, which is addressed in IPv6.

Of course, a number of very important features have not been discussed in this section, including QoS, mobile IP, autoconfiguration, and security. All these areas are extremely important, and until IPv6 is finished, you should keep referring to the IETF Web site for the most current information. Several new books on IPv6 also are starting to show up on bookstore shelves and should provide the deeper technical detail on address headers and full packet details.

Review Questions

Q—What is the current standard?

A—IPv4.

Q—What is the main reason for IPv6 being developed?

A—The main issue surrounding IPv6 is addressing, or the lack of addressing. Many people believe that we are nearly out of the four billion addresses available in IPv4. IPv6 could be the solution to many problems, but IPv6 is still not fully developed and is not yet a standard.

Q—How many bits does the new expanded addressing provide?

A—The expanded addressing moves us from 32-bit address to a 128-bit addressing method.

Q—What other benefits does expanded addressing provide?

A—It provides newer unicast and broadcasting methods. Expanded addressing also injects hexadecimal into the IP address and moves from using "." to using ":" as delimiters.

Q—What are the new broadcast methods included in IPv6?

A—Unicast, multicast, and anycast.

Q—What is unicast?

A— Unicast is a communication between a single host and a single receiver.

Q—What is multicast?

A—Multicast is communication between a single host and multiple receivers.

Q—What is anycast?

A— Anycast is a communication between a single sender and a list of addresses.

For More Information

http://www-6bone.lbl.gov/6bone

www.cisco.com/ipv6

http://www.ietf.org/html.charters/ipngwg-charter.html

http://playground.Sun.COM:80/pub/ipng/html

CCNA Discovery 3 - Module 1 Exam Answers Version 4.0

1. What can be found at the enterprise edge?
• Internet, VPN, and WAN modules
• Internet, PSTN, and WAN services
• server farms and network management
• campus infrastructure, including access layer devices

2. In which functional area of the Cisco Enterprise Architecture should IDS and IPS be located to detect
• and prevent services from accessing hosts?
• Enterprise Campus
• Edge Distribution
• Enterprise Edge
• Service Provider Edge

3. A business consultant must use Internet websites to research a report on the e-business strategies of several firms and then electronically deliver the report to a group of clients in cities throughout the world. Which two teleworker tools can the consultant use to accomplish this project? (Choose two.)
• VoIP
• VPN
• HTTP
• Telnet
• email

4. Which two measures help ensure that a hardware problem does not cause an outage in an enterprise LAN that supports mission critical services? (Choose two.)
• providing failover capability
• installing redundant power supplies
• purchasing more bandwidth from the ISP
• implementing broadcast containment with VLANs
• installing routers that can handle a greater amount of throughput

5. Which task would typically only require services located at the access layer of the hierarchical design model?
• connecting to the corporate web server to update sales figures
• using a VPN from home to send data to the main office servers
• printing a meeting agenda on a local departmental network printer
• placing a VoIP call to a business associate in another country
• responding to an e-mail from a co-worker in another department

6. How does a VPN work to support remote user productivity?
• It uses SSL to encrypt remote user logins to the corporate intranet.
• It uses secure Telnet for remote user connections to internal network devices.
• It creates a virtual circuit that allows real-time communications between any two Internet endpoints.
• It uses encapsulation to create a secure tunnel for transmission of data across non-secure networks.****

7. A remote user needs to access a networking device on the internal network of the company. The transactions between the remote user and the device must be secure. Which protocol enables this to happen securely?
• HTTP
• SSH
• Telnet
• FTP

8. What does VoIP provide to telecommuters?
• high-quality, live-video presentations
• real-time voice communications over the Internet
• ability to share desktop applications simultaneously
• secure, encrypted data transmissions through the Internet

9. Which functional component of the Cisco Enterprise Architecture is responsible for hosting internal servers?
• enterprise campus
• enterprise edge
• service provider edge
• building distribution

10. What is the purpose of the Cisco Enterprise Architecture?
• remove the three-layer hierarchical model and use a flat network approach
• divide the network into functional components while still maintaining the concept of Core, Distribution, and Access Layers
• provide services and functionality to the core layer by grouping various components into a single
• component located in the access layer
• reduce overall network traffic by grouping server farms, the management server, corporate intranet, and e-commerce routers in the same layer

11. Which two solutions would an enterprise IT department use to facilitate secure intranet access for remote workers? (Choose two.)
• VPN
• NAT
• user authentication
• client firewall software
• packet sniffing

12. Which statement describes the difference between an enterprise WAN and an enterprise extranet?
• An enterprise WAN is designed to interconnect local LANs, while an enterprise extranet is designed to interconnect remote branch offices.
• An enterprise WAN is designed to interconnect branch offices, while an enterprise extranet is designed to give access to external business partners.
• An enterprise WAN is designed to provide remote access for its teleworkers, while an enterprise extranet is designed to provide Internet connectivity for the enterprise.
• An enterprise WAN is designed to provide Internet connectivity for the enterprise, while an enterprise extranet is designed to provide remote access to the enterprise network for teleworkers.

13. Why would a network administrator want to limit the size of failure domains when designing a network?
• reduces the effect of Ethernet collisions
• reduces the impact of a key device or service failure
• reduces the impact of Internet congestion on critical traffic
• reduces the impact of blocking broadcast packets at the edge of the local network

14. What is the main purpose of the Access Layer in a hierarchically designed network?
• performs routing and packet manipulation
• supplies redundancy and failover protection
• provides a high-speed, low-latency backbone
• serves as a network connection point for end-user devices

15. Which three functions are performed at the Distribution Layer of the hierarchical network model? (Choose three.)
• forwards traffic that is destined for other networks
• isolates network problems to prevent them from affecting the Core Layer
• allows end users to access the local network
• provides a connection point for separate local networks
• transports large amounts of data between different geographic sites
• forwards traffic to other hosts on the same logical network

16. What is a benefit of having an extranet?
• It provides web-like access to company information for employees only.
• It limits access to corporate information to secure VPN or remote access connections only.
• It allows customers and partners to access company information by connecting to a public web server.
• It allows suppliers and contractors to access confidential internal information using controlled external connections.

17. What are two important characteristics or functions of devices at the Enterprise Edge? (Choose two.)
• providing Internet, telephone, and WAN services to the enterprise network
• providing a connection point for end-user devices to the enterprise network
• providing high-speed backbone connectivity with redundant connections
• providing intrusion detection and intrusion prevention to protect the network against malicious activity
• providing packet inspection to determine if incoming packets should be allowed on the enterprise network

18. Why is TCP the preferred Layer 4 protocol for transmitting data files?
• TCP is more reliable than UDP because it requires lost packets to be retransmitted.
• TCP requires less processing by the source and destination hosts than UDP.
• UDP introduces delays that degrade the quality of the data applications.
• TCP ensures fast delivery because it does not require sequencing or acknowlegements.

19. The ABC Corporation implements the network for its new headquarters using the Cisco Enterprise Architecture. The network administrator wants to filter the traffic from and to the outside world. Where should the administrator deploy a firewall device?
• server farm
• enterprise edge
• enterprise campus
• service provider edge

20. Which two statements are reasons why UDP is used for voice and video traffic instead of TCP?(Choose two.)
• TCP requires all data packets to be delivered for the data to be usable.
• The acknowledgment process of TCP introduces delays that break the streams of data.
• UDP does not have mechanisms for retransmitting lost packets.
• UDP tolerates delays and compensates for them.
• TCP is a connectionless protocol that provides end-to-end reliability.
• UDP is a connection-oriented protocol that provides end-to-end reliability.

CCNA Discovery 4 - Module 8 Exam Answers V.4

1. Which mechanism is used to create a floating static route?
• administrative distance
• cost
• hop count
• passive interface

2. IPSec operates at which layer of the OSI model?
• application
• network
• datalink
• transport

3. Which is true regarding Frame Relay LMI?
• There are three LMI types standardized by ANSI, ITU-T, and Cisco.
• Routers at each end of a Frame Relay virtual circuit must always use the same LMI type.
• The LMI type must be manually configured.
• The only function of LMI is to verify the connection between the router and the Frame Relay switch.

4. Which statement identifies the IP address design for subinterfaces that are configured for a Frame Relay network?
• Multipoint configurations require the IP address of each subinterface on each router to be in its own subnet.
• Multipoint configurations require IP addresses for each subinterface on each router to be a part of the same subnet.
• Point-to-point configurations require IP addresses for each subinterface on each router to be a part of the same subnet.
• Point-to-point configurations do not require IP addresses on each subinterface on each router.
• Multipoint configurations do not require IP addresses on each subinterface on each router.

5. Which three algorithms can be used to encrypt user data in an IPSec VPN framework? (Choose three.)
• 3DES
• AES
• Diffie-Hellman
• DES
• ESP
• SHA

6. Which flag is set by a Frame Relay switch to inform the receiving station that congestion was experienced?
• BECN
• DE
• FECN
• FCS

7. Refer to the exhibit. The complete configuration of a Frame Relay interface on the Chicago router is shown. How does the Chicago router know which DLCI is mapped to the IP address of the remote router?
• DE
• CIR
• FECN
• Inverse ARP

8. What statement correctly defines the purpose of the split horizon rule?
• marks the route unreachable in a routing update that is sent to other routers
• prevents routers from advertising a network through the interface from which the update came
• prevents routers from accepting higher cost routes to networks previously marked as inaccessible before the timer expires
• limits the number of hops a packet can traverse through the network before it should be discarded

9. Which PVC status suggests that the router recognizes the DLCI configured on its interface as being present on the Frame Relay switch, but the PVC associated with the DLCI is not capable of end-to-end communication?
• active
• deleted
• inactive
• idle

10. Refer to the exhibit. Which router command is used to associate a Layer 2 address with the corresponding Layer 3 address?
• Miller(config-if)#frame-relay map ip 172.16.150.1 110
• Miller(config-if)#frame-relay map ip 172.16.150.1 112
• Miller(config-if)#frame-relay map ip 172.16.150.2 110
• Miller(config-if)#frame-relay map ip 172.16.150.2 112

11. A network administrator issued the command show frame-relay pvc. The response from the router shows the status of a PVC as deleted. What is the reason for this status?
• The DLCI is using the wrong LMI type.
• The DLCI is usable but has little activity.
• The DLCI is programmed in the switch but the circuit is not usable.
• The DLCI configured on the CPE device does not match the DLCI.

12. What is one benefit of using a network simulation software package?
• The network design can be tested before it is actually implemented.
• Simulation software packages are quickly updated to support new network technologies and devices.
• Simulated devices have the same features as actual devices, allowing for detection of all potential problems.
• Software packages can simulate all possible network traffic conditions, giving an accurate prediction of network performance.

13. What are two components a network designer considers when planning a VPN? (Choose two.)
• encryption algorithm for privacy and security
• encapsulation protocol to use when creating the VPN tunnel
• switching technology to optimize VPN WAN throughput
• tunneling technology for guarding against data corruption
• routing protocol on the gateway for optimum performance

14. When identifying VPN requirements for endpoint users, what care must be taken to protect the network when remote users log in from unsecured public locations?
• Ensure that the user has VPN client software that allows access to all internal resources.
• Ensure that the VPN user traffic does not slow down internally sourced traffic on the network.
• Ensure that there are no obstacles to hamper the users from accessing all internal resources.
• Ensure that remote users can only access network resources that are appropriate to their job function.

15. Which two components are key elements when implementing a VPN? (Choose two.)
• concentration
• encryption
• prioritization
• compression
• encapsulation

16. What tool can help ease the configuration of VPN servers on routers?
• Cisco SDM
• PIX Firewall
• Cisco VPN Concentrator
• Cisco Adaptive Security Appliances

17. What is used to identify the path to the next frame-relay switch in a Frame Relay network?
• CIR
• DLCI
• FECN
• BECN

18. Which two statements are true regarding VPN security? (Choose two.)
• Users may only establish a VPN connection from secure locations and never from public areas.
• Users that connect to a network through a VPN do not have to log in to resources on the network.
• Users that connect to a network through a VPN are are considered trusted users on the network.
• Users may establish a VPN connection from unsecure locations such as airports and hotel lobbies.
• Users that connect to a network through a VPN should have access to all the resources on the network.

19. Refer to the exhibit. What is placed in the address field of a frame that will travel from the Orlando office to the DC office?
• MAC address of the Orlando router
• MAC address of the DC router
• 192.168.1.25
• 192.168.1.26
• DLCI 100
• DLCI 200

20. Two directly connected routers are able to ping each other through the Serial 0/0/0 interfaces. A network administrator changes the encapsulation on one router to PPP, and the other is left at the default value. What statement would appear in the output of the show interfaces command issued on one of the routers?
• Serial 0/0/0 is up, line protocol is up
• Serial 0/0/0 is down, line protocol is down
• Serial 0/0/0 is up, line protocol is down
• Serial 0/0/0 is down, line protocol is up
• Serial 0/0/0 is administratively down, line protocol is down

21. Refer to the exhibit. What statement is true about the configuration shown for R2?
• R2 is configured as the Frame Relay switch.
• R2 is configured as the main site in a multipoint Frame Relay WAN prototype.
• R2 is configured as the main site in a point-to-point Frame Relay WAN prototype.
• R2 is configured as a remote site in a multipoint Frame Relay WAN prototype.
• R2 is configured as a remote site in a point-to-point Frame Relay WAN prototype.

22. A company uses serial interfaces on its border router to connect to branch offices through WAN connections. The security policy dictates that the encapsulation should use PPP with authentication protocol CHAP. Which statement is true about the configuration requirement of CHAP?
• Both the username and password are case sensitive.
• Neither the username nor the password is case sensitive.
• The username is case sensitive but the password is not case sensitive.
• The password is case sensitive but the username is not case sensitive.

23. Which two statements about split tunnels are true? (Choose two.)
• Local LAN printing will use the VPN tunnel.
• The traffic load on the VPN server is increased.
• Traffic to the corporate network will be encrypted.
• There is a reduced security risk to the corporate network.
• All traffic travels across the VPN tunnel from client to server.
• Traffic to public web sites and general Internet navigation is not encrypted.

24. An IP address has been assigned to the S0/0/0 interface of a new Cisco router. The administrator wishes to quickly test basic connectivity with the serial interface of an adjoining Cisco router via the use of the default WAN protocol. Which WAN protocol will be used for this test?
• PPP
• Frame Relay
• DSL
• HDLC
• ATM

25. Which two statements about split tunnels are true? (Choose two.)
• Local LAN printing will use the VPN tunnel.
• The traffic load on the VPN server is increased.
• Traffic to the corporate network will be encrypted.
• There is a reduced security risk to the corporate network.
• All traffic travels across the VPN tunnel from client to server.
• Traffic to public web sites and general Internet navigation is not encrypted.

Protecting Against an IP Spoofing Attack

The following approaches can be used to mitigate IP spoofing attacks:



¦ Use access control lists (ACL) on router interfaces. As traffic comes into a router from

an outside network, an ACL could be used to deny any outside traffic claiming to be

addressed with IP addressing used internally on the local network. Conversely, ACLs

should be used to prevent traffic leaving the local network from participating in a

DDoS attack. Therefore, an ACL could deny any traffic leaving the local network that

claimed to have a source address that was different from the internal network’s IP

address space.



¦ Encrypt traffic between devices (for example, between two routers, or between an end

system and a router) via an IPsec tunnel. In Figure 1-7, notice that the topology is now

protected with an IPsec tunnel. Even though the attacker can still capture packets via

his rogue hub, the captured packets are unreadable, because the traffic is encrypted

inside the IPsec tunnel.



Figure 1-7 Protecting Traffic in a Tunnel

CCNA Discovery 4 - Module 7 Exam Answers V.4

1. A network engineer has decided to pilot test a portion of a new network design rather than rely on a prototype for proof-of-concept. What are two advantages of pilot testing a design concept?(Choose two.)
• The test network experiences real-world network traffic.
• Users within the enterprise are not affected by the test.
• Network response can be tested in unplanned and unpredictable situations.
• Unlikely failure conditions can be conveniently tested.
• Network response can be tested in a highly controlled simulated environment.

2. While preparing a network test plan document, a network designer records all initial and modified device configurations. Which section of the document typically contains this information?
• Appendix
• Test Procedures
• Test Description
• Actual Results and Conclusions
• Anticipated Results and Success Criteria

3. Refer to the exhibit. A network designer creates a test plan that includes the specification shown. In which section of the test plan would this specification be found?
• Test Description
• Test Procedures
• Design and Topology Diagram
• Actual Results and Conclusions
• Anticipated Results and Success Criteria

4. What OSI model Layer 2 security measure can a network engineer implement when prototyping network security?
• a firewall at the network edge
• port security at the access design layer
• port security at the distribution design layer
• IP access control lists at the access design layer

5. How do designers decide which network functions need to be included in the prototype test?
• They select the functions that align with the business goals.
• They select the functions that occur at the network core.
• They select the functions that do not exist in the existing network.
• They select the functions from a list of generic network operations.

6. Refer to the exhibit. During prototype testing of the Cisco network shown, connectivity must be verified. Assuming all connections are working and CDP is enabled on all devices and interfaces, on which device was the command issued?
• R1
• S1
• R3
• S2
• R5
• S3

7. Refer to the exhibit. During prototyping, Layer 2 functionality is being tested. Based on the output shown, which two pieces of information can be determined? (Choose two.)
• Switch1 is the root bridge.
• Interface Fa0/2 on Switch1 has no role in the operation of spanning tree.
• Interface Fa0/2 on Switch1 is the alternate port used to reach the root bridge.
• Based on the entries in the "Role" column, it can be concluded that RSTP has been implemented.
• Interface Fa0/1 on Switch1 is the forwarding port selected for the entire spanning-tree topology.

8. What Rapid Spanning Tree Protocol (RSTP) state is given to the forwarding port elected for every switched Ethernet LAN segment?
• root
• backup
• alternate
• designated

9. Refer to the exhibit. During prototype testing, verification of VLAN connectivity is being performed. Based on the information shown, what command produced the output?
• show spanning-tree
• show interfaces trunk
• show cdp neighbors
• show interfaces
• show ip interface brief

10. Switch port Fa0/24 was previously configured as a trunk, but now it is to be used to connect a host to the network. How should the network administrator reconfigure switch port Fa0/24?
• Use the switchport mode access command from interface configuration mode.
• Enter the switchport nonegotiate command from interface configuration mode.
• Administratively shut down and re-enable the interface to return it to the default.
• Enter the no switchport mode trunk command in interface configuration mode.
• Use the switchport access vlan vlan number command from interface configuration mode
• to remove the port from the trunk and add it to a specific VLAN.

11. Refer to the exhibit. The redundant paths are of equal bandwidth and EIGRP is the routing protocol in use. Which statement describes the data flow from Server to PC2?
• EIGRP load balances across the R3 to R1 and R3 to R2 links.
• EIGRP load balances across the R1 to Switch3 and R2 to Switch3 paths.
• EIGRP load balances across the Switch1 to Switch3 and Switch1 to Switch2 paths.
• EIGRP does not load balance in this topology.

12. A network designer needs to determine if a proposed IP addressing scheme allows efficient route summarization and provides the appropriate amount of scalability to a design. What is useful for validating a proposed hierarchical IP addressing scheme?
• NBAR
• a pilot network
• a route summary
• a network simulator
• a physical topology ma

13. In the router command encapsulation dot1q 10, what does the number 10 represent?
• the metric used for a particular route
• the number of the VLAN associated with the encapsulated subinterface
• the priority number given to the device for the election process
• the number that must match the Fast Ethernet subinterface number
• the number used to program the router for unequal cost path load balancing

14. Refer to the exhibit. The users on the 192.168.10.192 network are not allowed Internet access. The network design calls for an extended ACL to be developed and tested. Where should the ACL be placed for the least effect on other network traffic?
• inbound on Fa0/0 of R3
• outbound on Fa0/0 of R3
• inbound on Fa0/1 of R3
• outbound on Fa0/1 of R3
• inbound on Fa0/1 of R2
• outbound on S0/0 of R2

15. Refer to the exhibit. What two measures can be taken to address the areas of weakness circled in the network design? (Choose two.)
• Provide redundant connections to all end users.
• Add another core switch to increase redundancy.
• Add a switch in the server block connecting the server farm to each core switch.
• Add an additional switch to the DMZ and direct links from the new switch to the core switches.
• Provide a redundant firewall router connecting to a second ISP, the core switches, and the DMZ.

16. Why is it important to record baseline measurements of a prototype network?
• Test results show security weaknesses after the baseline tests are run.
• The baseline is the point at which the network is operating at its fullest potential.
• Baseline measurements define a point at which network traffic has exceeded the designed capabilities of the network.
• Test results are compared to the baseline to see how the test conditions increase processor use or decrease available bandwidth.

17. Refer to the exhibit. A network administrator has been given the task of creating a design for a temporary classroom building that is to be set up outside an overcrowded school. In testing the prototype, it is found that the student PC cannot ping the teacher PC. All the switch interfaces are active and connected properly, as is interface Fa0/0 of the router. Given that only the commands shown have bee added to the router configuration, what is the source of the problem?
• The IP settings on the student PC are incorrect.
• The default gateway on the teacher PC is misconfigured.
• The router Fa0/0 interface has not been configured as a VLAN trunk.
• The Fa0/0 physical interface has not been configured with an IP address and subnet mask.
• The administrator forgot to configure a routing protocol to allow the ping packets to reach the teacher PC subnet.

18. Refer to the exhibit. Why are interfaces Fa0/11, Fa0/23, and Fa0/24 not shown in this switch output?
• Interfaces Fa0/11, Fa0/23, and Fa0/24 are trunks.
• Interfaces Fa0/11, Fa0/23, and Fa0/24 are shutdown.
• Interfaces Fa0/11, Fa0/23, and Fa0/24 are blocking.
• Interfaces Fa0/11, Fa0/23, and Fa0/24 failed diagnostics

19. Refer to the exhibit. A network technician is performing an initial installation of a new switch in the east wing. The technician removes the switch from the box, makes the connections to the network, and adds the configuration shown. The technician notifies the network administrator that the switch has been installed. When the network administrator at the home office attempts to telnet to the switch from host 192.168.0.1, the connection fails. What action should the network technician take?
• Add an enable password to the switch.
• Add a default gateway to the switch configuration.
• Configure the switch with an IP access list to permit the host connection.
• Enable the physical interfaces of the switch with the no shutdown command.

20. Refer to the exhibit. After all the interfaces have stabilized, what is the spanning-tree state of all the enabled interfaces of SW11?
• discarding
• forwarding
• learning
• listening