Free 2014 Latest Cisco 200-120 Dump (51-60) Download!

QUESTION 51
On a corporate network, hosts on the same VLAN can communicate with each other, but they are unable to communicate with hosts on different VLANs. What is needed to allow communication between the VLANs?

A.    a router with subinterfaces configured on the physical interface that is connected to the switch
B.    a router with an IP address on the physical interface connected to the switch
C.    a switch with an access link that is configured between the switches
D.    a switch with a trunk link that is configured between the switches

Answer: A
Explanation:
Different VLANs can’t communicate with each other , they can communicate with the help of Layer3 router. Hence , it is needed to connect a router to a switch , then make the sub-interface on the router to connect to the switch, establishing Trunking links to achieve communications of devices which belong to different VLANs.
When using VLANs in networks that have multiple interconnected switches, you need to use VLAN trunking between the switches. With VLAN trunking, the switches tag each frame sent between switches so that the receiving switch knows to what VLAN the frame belongs. End user devices connect to switch ports that provide simple connectivity to a single VLAN each. The attached devices are unaware of any VLAN structure.
By default, only hosts that are members of the same VLAN can communicate. To change this and allow inter-VLAN communication, you need a router or a layer 3 switch.
Here is the example of configuring the router for inter-vlan communication RouterA(config)#int f0/0.1
RouterA(config-subif)#encapsulation ?
dot1Q IEEE 802.1Q Virtual LAN
RouterA(config-subif)#encapsulation dot1Q or isl VLAN ID RouterA(config-subif)# ip address x.x.x.x y.y.y.y

QUESTION 52
Which command displays CPU utilization?

A.    show protocols
B.    show process
C.    show system
D.    show version

Answer: B
Explanation:
The “show process” (in fact, the full command is “show processes”) command gives us lots of information about each process but in fact it is not easy to read. Below shows the output of this command (some next pages are omitted)

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A more friendly way to check the CPU utilization is the command “show processes cpu history”, in which the total CPU usage on the router over a period of time: one minute, one hour, and 72 hours are clearly shown:

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+ The Y-axis of the graph is the CPU utilization.+ The X-axis of the graph is the increment within the period displayed in the graph
For example, from the last graph (last 72 hours) we learn that the highest CPU utilization within 72 hours is 37% about six hours ago.

QUESTION 53
What two things will a router do when running a distance vector routing protocol? (Choose two.)

A.    Send periodic updates regardless of topology changes.
B.    Send entire routing table to all routers in the routing domain.
C.    Use the shortest-path algorithm to the determine best path.
D.    Update the routing table based on updates from their neighbors.
E.    Maintain the topology of the entire network in its database.

Answer: AD
Explanation:
Distance means how far and Vector means in which direction. Distance Vector routing protocols pass periodic copies of routing table to neighbor routers and accumulate distance vectors. In distance vector routing protocols, routers discover the best path to destination from each neighbor. The routing updates proceed step by step from router to router.

QUESTION 54
Which command is used to display the collection of OSPF link states?

A.    show ip ospf link-state
B.    show ip ospf lsa database
C.    show ip ospf neighbors
D.    show ip ospf database

Answer: D
Explanation:
The “show ip ospf database” command displays the link states. Here is an example:
Here is the lsa database on R2.
R2#show ip ospf database
OSPF Router with ID (2.2.2.2) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count2.2.2.2 2.2.2.2 793 0x80000003 0x004F85 210.4.4.4 10.4.4.4 776 0x80000004 0x005643 1111.111.111.111 111.111.111.111 755 0x80000005 0x0059CA 2133.133.133.133 133.133.133.133 775 0x80000005 0x00B5B1 2 Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum10.1.1.1 111.111.111.111 794 0x80000001 0x001E8B10.2.2.3 133.133.133.133 812 0x80000001 0x004BA910.4.4.1 111.111.111.111 755 0x80000001 0x007F1610.4.4.3 133.133.133.133 775 0x80000001 0x00C31F

QUESTION 55
If IP routing is enabled, which two commands set the gateway of last resort to the default gateway? (Choose two.)

A.    ip default-gateway 0.0.0.0
B.    ip route 172.16.2.1 0.0.0.0 0.0.0.0
C.    ip default-network 0.0.0.0
D.    ip default-route 0.0.0.0 0.0.0.0 172.16.2.1
E.    ip route 0.0.0.0 0.0.0.0 172.16.2.1

Answer: CE
Explanation:
Both the “ip default-network” and “ip route 0.0.0.0 0.0.0.0 (next hop)” commands can be used to set the default gateway in a Cisco router.

QUESTION 56
Which parameter would you tune to affect the selection of a static route as a backup, when a dynamic protocol is also being used?

A.    hop count
B.    administrative distance
C.    link bandwidth
D.    link delay
E.    link cost

Answer: B
Explanation:
By default the administrative distance of a static route is 1, meaning it will be preferred over all dynamic routing protocols. If you want to have the dynamic routing protocol used and have the static route be used only as a backup, you need to increase the AD of the static route so that it is higher than the dynamic routing protocol.

QUESTION 57
Before installing a new, upgraded version of the IOS, what should be checked on the router, and which command should be used to gather this information? (Choose two.)

A.    the amount of available ROM
B.    the amount of available flash and RAM memory
C.    the version of the bootstrap software present on the router
D.    show version
E.    show processes
F.    show running-config

Answer: BD
Explanation:
When upgrading new version of the IOS we need to copy the IOS to the Flash so first we have to check if the Flash has enough memory or not. Also running the new IOS may require more RAM than the older one so we should check the available RAM too. We can check both with the “show version” command.

QUESTION 58
Which command reveals the last method used to powercycle a router?

A.    show reload
B.    show boot
C.    show running-config
D.    show version

Answer: D
Explanation:
The “show version” command can be used to show the last method to powercycle (reset) a router

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QUESTION 59
Which command would you use on a Cisco router to verify the Layer 3 path to a host?

A.    tracert address
B.    traceroute address
C.    telnet address
D.    ssh address

Answer: B
Explanation:
In computing, traceroute is a computer network diagnostic tool for displaying the route (path) and
measuring transit delays of packets across an Internet Protocol (IP) network. The history of the route is recorded as the round-trip times of the packets received from each successive host (remote node) in the route (path); the sum of the mean times in each hop indicates the total time spent to establish the connection. Traceroute proceeds unless all (three) sent packets are lost more than twice, then the connection is lost and the route cannot be evaluated. Ping, on the other hand, only computes the final round-trip times from the destination point.

QUESTION 60
What information does a router running a link-state protocol use to build and maintain its topological database? (Choose two.)

A.    hello packets
B.    SAP messages sent by other routers
C.    LSAs from other routers
D.    beacons received on point-to-point links
E.    routing tables received from other link-state routers
F.    TTL packets from designated routers

Answer: AC
Explanation:
Neighbor discovery is the first step in getting a link state environment up and running. In keeping with the friendly neighbor terminology, a Hello protocol is used for this step. The protocol will define a Hello packet format and a procedure for exchanging the packets and processing the information the packets contain.
After the adjacencies are established, the routers may begin sending out LSAs. As the term flooding implies, the advertisements are sent to every neighbor. In turn, each received LSA is copied and forwarded to every neighbor except the one that sent the LSA.

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QUESTION 41
How is an EUI-64 format interface ID created from a 48-bit MAC address?

A.    by appending 0xFF to the MAC address
B.    by prefixing the MAC address with 0xFFEE
C.    by prefixing the MAC address with 0xFF and appending 0xFF to it
D.    by inserting 0xFFFE between the upper three bytes and the lower three bytes of the MAC address
E.    by prefixing the MAC address with 0xF and inserting 0xF after each of its first three bytes

Answer: D
Explanation:
The modified EUI-64 format interface identifier is derived from the 48-bit link-layer (MAC) address by inserting the hexadecimal number FFFE between the upper three bytes (OUI field) and the lower three bytes (serial number) of the link layer address.

QUESTION 42
Which option is a valid IPv6 address?

A.    2001:0000:130F::099a::12a
B.    2002:7654:A1AD:61:81AF:CCC1
C.    FEC0:ABCD:WXYZ:0067::2A4
D.    2004:1:25A4:886F::1

Answer: D
Explanation:
An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets). The groups are separated by colons (:). An example of an IPv6 address is 2001:0db8:85a3:0000:0000:8a2e:0370:7334. The leading 0’s in a group can be collapsed using ::, but this can only be done once in an IP address.

QUESTION 43
Which three are characteristics of an IPv6 anycast address? (Choose three.)

A.    one-to-many communication model
B.    one-to-nearest communication model
C.    any-to-many communication model
D.    a unique IPv6 address for each device in the group
E.    the same address for multiple devices in the group
F.    delivery of packets to the group interface that is closest to the sending device

Answer: BEF
Explanation:
A new address type made specifically for IPv6 is called the Anycast Address. These IPv6 addresses are global addresses, these addresses can be assigned to more than one interface unlike an IPv6 unicast
address. Anycast is designed to send a packet to the nearest interface that is apart of that anycast group.
The sender creates a packet and forwards the packet to the anycast address as the destination address which goes to the nearest router. The nearest router or interface is found by using the metric of a routing protocol currently running on the network. However in a LAN setting the nearest interface is found depending on the order the neighbors were learned. The anycast packet in a LAN setting forwards the packet to the neighbor it learned about first.

QUESTION 44
A national retail chain needs to design an IP addressing scheme to support a nationwide network. The company needs a minimum of 300 sub-networks and a maximum of 50 host addresses per subnet. Working with only one Class B address, which of the following subnet masks will support an appropriate addressing scheme? (Choose two.)

A.    255.255.255.0
B.    255.255.255.128
C.    255.255.252.0
D.    255.255.255.224
E.    255.255.255.192
F.    255.255.248.0

Answer: BE
Explanation:
Subnetting is used to break the network into smaller more efficient subnets to prevent excessive rates of Ethernet packet collision in a large network. Such subnets can be arranged hierarchically, with the organization’s network address space (see also Autonomous System) partitioned into a tree-like structure. Routers are used to manage traffic and constitute borders between subnets. A routing prefix is the sequence of leading bits of an IP address that precede the portion of the address used as host identifier. In IPv4 networks, the routing prefix is often expressed as a “subnet mask”, which is a bit mask covering the number of bits used in the prefix. An IPv4 subnet mask is frequently expressed in quad-dotted decimal representation, e.g., 255.255.255.0 is the subnet mask for the 192.168.1.0 network with a 24-bit routing prefix (192.168.1.0/24).

QUESTION 45
Which IPv6 address is the all-router multicast group?

A.    FF02::1
B.    FF02::2
C.    FF02::3
D.    FF02::4

Answer: B
Explanation:
Well-known IPv6 multicast addresses:
Address
Description
ff02::1
All nodes on the local network segment
ff02::2
All routers on the local network segment

QUESTION 46
Which IPv6 address is valid?

A.    2001:0db8:0000:130F:0000:0000:08GC:140B
B.    2001:0db8:0:130H::87C:140B
C.    2031::130F::9C0:876A:130B
D.    2031:0:130F::9C0:876A:130B

Answer: D
Explanation:
An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets). The groups are separated by colons (:). An example of an IPv6 address is 2001:0db8:85a3:0000:0000:8a2e:0370:7334. The leading 0’s in a group can be collapsed using ::, but this can only be done once in an IP address.

QUESTION 47
Which command can you use to manually assign a static IPv6 address to a router interface?

A.    ipv6 autoconfig 2001:db8:2222:7272::72/64
B.    ipv6 address 2001:db8:2222:7272::72/64
C.    ipv6 address PREFIX_1 ::1/64
D.    ipv6 autoconfig

Answer: B
Explanation:
To assign an IPv6 address to an interface, use the “ipv6 address” command and specify the IP address you wish to use.

QUESTION 48
Which of these represents an IPv6 link-local address?

A.    FE80::380e:611a:e14f:3d69
B.    FE81::280f:512b:e14f:3d69
C.    FEFE:0345:5f1b::e14d:3d69
D.    FE08::280e:611:a:f14f:3d69

Answer: A
Explanation:
In the Internet Protocol Version 6 (IPv6), the address block fe80::/10 has been reserved for link- local unicast addressing. The actual link local addresses are assigned with the prefix fe80::/64. They may be assigned by automatic (stateless) or stateful (e.g. manual) mechanisms.

QUESTION 49
The network administrator is asked to configure 113 point-to-point links. Which IP addressing scheme defines the address range and subnet mask that meet the requirement and waste the fewest subnet and host addresses?

A.    10.10.0.0/16 subnetted with mask 255.255.255.252
B.    10.10.0.0/18 subnetted with mask 255.255.255.252
C.    10.10.1.0/24 subnetted with mask 255.255.255.252
D.    10.10.0.0/23 subnetted with mask 255.255.255.252
E.    10.10.1.0/25 subnetted with mask 255.255.255.252

Answer: D
Explanation:
We need 113 point-to-point links which equal to 113 sub-networks < 128 so we need to borrow 7 bits (because 2^7 = 128).
The network used for point-to-point connection should be /30.
So our initial network should be 30 ?7 = 23.
So 10.10.0.0/23 is the correct answer.
You can understand it more clearly when writing it in binary form:
/23 = 1111 1111.1111 1110.0000 0000
/30 = 1111 1111.1111 1111.1111 1100 (borrow 7 bits)

QUESTION 50
A Cisco router is booting and has just completed the POST process. It is now ready to find and load an IOS image. What function does the router perform next?

A.    It checks the configuration register.
B.    It attempts to boot from a TFTP server.
C.    It loads the first image file in flash memory.
D.    It inspects the configuration file in NVRAM for boot instructions.

Answer: A
Explanation:
Default (normal) Boot SequencePower on Router – Router does POST – Bootstrap starts IOS load – Check configuration registerto see what mode the router should boot up in (usually 0x2102
to read startup-config in NVRAM / or 0x2142 to start in “setup-mode”) – check the startup-config file in NVRAM for boot-system commands – load IOS from Flash.

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QUESTION 31
Three switches are connected to one another via trunk ports. Assuming the default switch configuration, which switch is elected as the root bridge for the spanning-tree instance of VLAN 1?

A.    the switch with the highest MAC address
B.    the switch with the lowest MAC address
C.    the switch with the highest IP address
D.    the switch with the lowest IP address

Answer: B
Explanation:
Each switch in your network will have a Bridge ID Priority value, more commonly referred to as a BID. This BID is a combination of a default priority value and the switch’s MAC address, with the priority value listed first. The lowest BID will win the election process.
For example, if a Cisco switch has the default priority value of 32,768 and a MAC address of 11- 22-33-44-55-66, the BID would be 32768:11-22-33-44-55-66. Therefore, if the switch priority is left at the default, the MAC address is the deciding factor in the root bridge election.

QUESTION 32
What are three advantages of VLANs? (Choose three.)

A.    VLANs establish broadcast domains in switched networks.
B.    VLANs utilize packet filtering to enhance network security.
C.    VLANs provide a method of conserving IP addresses in large networks.
D.    VLANs provide a low-latency internetworking alternative to routed networks.
E.    VLANs allow access to network services based on department, not physical location.
F.    VLANs can greatly simplify adding, moving, or changing hosts on the network.

Answer: AEF
Explanation:
VLAN technology is often used in practice, because it can better control layer2 broadcast to improve network security. This makes network more flexible and scalable. Packet filtering is a function of firewall instead of VLAN.

QUESTION 33
Which two benefits are provided by using a hierarchical addressing network addressing scheme? (Choose two.)

A.    reduces routing table entries
B.    auto-negotiation of media rates
C.    efficient utilization of MAC addresses
D.    dedicated communications between devices
E.    ease of management and troubleshooting

Answer: AE
Explanation:
Here are some of the benefits of hierarchical addressing:
Reference: http://www.ciscopress.com/articles/article.asp?p=174107

QUESTION 34
What is the alternative notation for the IPv6 address B514:82C3:0000:0000:0029:EC7A:0000:EC72?

A.    B514 : 82C3 : 0029 : EC7A : EC72
B.    B514 : 82C3 :: 0029 : EC7A : EC72
C.    B514 : 82C3 : 0029 :: EC7A : 0000 : EC72
D.    B514 : 82C3 :: 0029 : EC7A : 0 : EC72

Answer: D
Explanation:
There are two ways that an IPv6 address can be additionally compressed: compressing leading
zeros and substituting a group of consecutive zeros with a single double colon (::). Both of these can be used in any number of combinations to notate the same address. It is important to note that the double colon (::) can only be used once within a single IPv6 address notation. So, the extra 0’s can only be compressed once.

QUESTION 35
Which two statements describe characteristics of IPv6 unicast addressing? (Choose two.)

A.    Global addresses start with 2000::/3.
B.    Link-local addresses start with FE00:/12.
C.    Link-local addresses start with FF00::/10.
D.    There is only one loopback address and it is ::1.
E.    If a global address is assigned to an interface, then that is the only allowable address for the interface.

Answer: AD
Explanation:
Below is the list of common kinds of IPv6 addresses:
QUESTION 36
The network administrator has been asked to give reasons for moving from IPv4 to IPv6. What are two valid reasons for adopting IPv6 over IPv4? (Choose two.)

A.    no broadcast
B.    change of source address in the IPv6 header
C.    change of destination address in the IPv6 header
D.    Telnet access does not require a password
E.    autoconfiguration
F.    NAT

Answer: AE
Explanation:
IPv6 does not use broadcasts, and autoconfiguration is a feature of IPV6 that allows for hosts to automatically obtain an IPv6 address.

QUESTION 37
An administrator must assign static IP addresses to the servers in a network. For network 192.168.20.24/29, the router is assigned the first usable host address while the sales server is given the last usable host address. Which of the following should be entered into the IP properties box for the sales server?

A.    IP address: 192.168.20.14
Subnet Mask: 255.255.255.248
Default Gateway: 192.168.20.9
B.    IP address: 192.168.20.254
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.20.1
C.    IP address: 192.168.20.30
Subnet Mask: 255.255.255.248
Default Gateway: 192.168.20.25
D.    IP address: 192.168.20.30
Subnet Mask: 255.255.255.240
Default Gateway: 192.168.20.17
E.    IP address: 192.168.20.30
Subnet Mask: 255.255.255.240
Default Gateway: 192.168.20.25

Answer: C
Explanation:
For the 192.168.20.24/29 network, the usable hosts are 192.168.24.25 (router) ?192.168.24.30 (used for the sales server).

QUESTION 38
Which subnet mask would be appropriate for a network address range to be subnetted for up to eight LANs, with each LAN containing 5 to 26 hosts?

A.    0.0.0.240
B.    255.255.255.252
C.    255.255.255.0
D.    255.255.255.224
E.    255.255.255.240

Answer: D
Explanation:
For a class C network, a mask of 255.255.255.224 will allow for up to 8 networks with 32 IP addresses each (30 usable).

QUESTION 39
How many bits are contained in each field of an IPv6 address?

A.    24
B.    4
C.    8
D.    16

Answer: D
Explanation:
An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets). The groups are separated by colons (:). An example of an IPv6 address is 2001:0db8:85a3:0000:0000:8a2e:0370:7334.

QUESTION 40
What are three approaches that are used when migrating from an IPv4 addressing scheme to an IPv6 scheme. (Choose three.)

A.    enable dual-stack routing
B.    configure IPv6 directly
C.    configure IPv4 tunnels between IPv6 islands
D.    use proxying and translation to translate IPv6 packets into IPv4 packets
E.    statically map IPv4 addresses to IPv6 addresses
F.    use DHCPv6 to map IPv4 addresses to IPv6 addresses

Answer: ACD
Explanation:
Several methods are used terms of migration including tunneling, translators, and dual stack. Tunnels are used to carry one protocol inside another, while translators simply translate IPv6 packets into IPv4 packets. Dual stack uses a combination of both native IPv4 and IPv6. With dual stack, devices are able to run IPv4 and IPv6 together and if IPv6 communication is possible that is the preferred protocol. Hosts can simultaneously reach IPv4 and IPv6 content.

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QUESTION 21
Which two benefits are provided by creating VLANs? (Choose two.)

A.    added security
B.    dedicated bandwidth
C.    provides segmentation
D.    allows switches to route traffic between subinterfaces
E.    contains collisions

Answer: AC
Explanation:
A VLAN is a switched network that is logically segmented on an organizational basis, by functions, project teams, or applications rather than on a physical or geographical basis.
Security:
VLANs also improve security by isolating groups. High-security users can be grouped into a VLAN, possible on the same physical segment, and no users outside that VLAN can communicate with them
LAN Segmentation
VLANs allow logical network topologies to overlay the physical switched infrastructure such that any arbitrary collection of LAN ports can be combined into an autonomous user group or community of interest. The technology logically segments the network into separate Layer 2 broadcast domains whereby packets are switched between ports designated to be within the same VLAN. By containing traffic originating on a particular LAN only to other LANs in the same VLAN, switched virtual networks avoid wasting bandwidth.

QUESTION 22
Which command can be used from a PC to verify the connectivity between hosts that connect through a switch in the same LAN?

A.    pingaddress
B.    tracertaddress
C.    tracerouteaddress
D.    arpaddress

Answer: A
Explanation:
ICMP pings are used to verify connectivity between two IP hosts. Traceroute is used to verify the router hop path traffic will take but in this case since the hosts are in the same LAN there will be no router hops involved.

QUESTION 23
Which two of these are characteristics of the 802.1Q protocol? (Choose two.)

A.    It is used exclusively for tagging VLAN frames and does not address network reconvergence following
switched network topology changes.
B.    It modifies the 802.3 frame header, and thus requires that the FCS be recomputed.
C.    It is a Layer 2 messaging protocol which maintains VLAN configurations across networks.
D.    It includes an 8-bit field which specifies the priority of a frame.
E.    It is a trunking protocol capable of carrying untagged frames.

Answer: BE
Explanation:
802.1Q protocol, or Virtual Bridged Local Area Networks protocol, mainly stipulates the realization of the VLAN. 802.1Q is a standardized relay method that inserts 4 bytes field into the original Ethernet frame and re-calculate the FCS. 802.1Q frame relay supports two types of frame: marked and non-marked. Non-marked frame carries no VLAN identification information.

QUESTION 24
Refer to the exhibit. Each of these four switches has been configured with a hostname, as well as being configured to run RSTP. No other configuration changes have been made. Which three of these show the correct RSTP port roles for the indicated switches and interfaces? (Choose three.)

A.    SwitchA, Fa0/2, designated
B.    SwitchA, Fa0/1, root
C.    SwitchB, Gi0/2, root
D.    SwitchB, Gi0/1, designated
E.    SwitchC, Fa0/2, root
F.    SwitchD, Gi0/2, root

Answer: ABF
Explanation:
The question says “no other configuration changes have been made” so we can understand these switches have the same bridge priority. Switch C has lowest MAC address so it will become root bridge and 2 of its ports (Fa0/1 & Fa0/2) will be designated ports. Because SwitchC is the root bridge so the 2 ports nearest SwitchC on SwitchA (Fa0/1) and SwitchD (Gi0/2) will be root ports..
Now we come to the most difficult part of this question: SwitchB must have a root port so which port will it choose? To answer this question we need to know about STP cost and port cost. In general, “cost” is calculated based on bandwidth of the link. The higher the bandwidth on a link, the lower the value of its cost. Below are the cost values you should memorize:

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SwitchB will choose the interface with lower cost to the root bridge as the root port so we must calculate the cost on interface Gi0/1 & Gi0/2 of SwitchB to the root bridge. This can be calculated from the “cost to the root bridge” of each switch because a switch always advertises its cost to the root bridge in its BPDU. The receiving switch will add its local port cost value to the cost in the BPDU.
One more thing to notice is that a root bridge always advertises the cost to the root bridge (itself) with an initial value of 0.
Now let’s have a look at the topology again

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SwitchC advertises its cost to the root bridge with a value of 0. Switch D adds 4 (the cost value of 1Gbps link) and advertises this value (4) to SwitchB. SwitchB adds another 4 and learns that it can reach SwitchC via Gi0/1 port with a total cost of 8. The same process happens for SwitchA and SwitchB learns that it can reach SwitchC via Gi0/2 with a total cost of 23 -> Switch B chooses Gi0/1 as its root port ->
Now our last task is to identify the port roles of the ports between SwitchA & SwitchB. It is rather easy as the MAC address of SwitchA is lower than that of SwitchB so Fa0/2 of SwitchA will be designated port while Gi0/2 of SwitchB will be alternative port.
Below summaries all the port roles of these switches:

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+ DP: Designated Port (forwarding state)
+ RP: Root Port (forwarding state)

QUESTION 25
What is one benefit of PVST+?

A.    PVST+ supports Layer 3 load balancing without loops.
B.    PVST+ reduces the CPU cycles for all the switches in the network.
C.    PVST+ allows the root switch location to be optimized per VLAN.
D.    PVST+ automatically selects the root bridge location, to provide optimized bandwidth usage.

Answer: C
Explanation:
The PVST+ provides Layer 2 load-balancing for the VLAN on which it runs. You can create different logical topologies by using the VLANs on your network to ensure that all of your links are used but that no one link is oversubscribed. Each instance of PVST+ on a VLAN has a single root switch. This root switch propagates the spanning-tree information associated with that VLAN to all other switches in the network. Because each switch has the same information about the network, this process ensures that the network topology is maintained and optimized per VLAN.
Reference:
http://www.cisco.com/en/US/docs/switches/lan/catalyst3750x_3560x/software/release/12.2_55_se /configuration/guide/swstp.html

QUESTION 26
Which are valid modes for a switch port used as a VLAN trunk? (Choose three.)

A.    transparent
B.    auto
C.    on
D.    desirable
E.    blocking
F.    forwarding

Answer: BCD

QUESTION 27
Which three of these statements regarding 802.1Q trunking are correct? (Choose three.)

A.    802.1Q native VLAN frames are untagged by default.
B.    802.1Q trunking ports can also be secure ports.
C.    802.1Q trunks can use 10 Mb/s Ethernet interfaces.
D.    802.1Q trunks require full-duplex, point-to-point connectivity.
E.    802.1Q trunks should have native VLANs that are the same at both ends.

Answer: ACE
Explanation:
By default, 802.1Q trunk defined Native VLAN in order to forward unmarked frame. Switches can forward Layer 2 frame from Native VLAN on unmarked trunks port. Receiver switches will transmit all unmarked packets to Native VLAN. Native VLAN is the default VLAN configuration of port. Note for the 802.1Q trunk ports between two devices, the same Native VLAN configuration is required on both sides of the link. If the Native VLAN in 802.1Q trunk ports on same trunk link is properly configured, it could lead to layer 2 loops. The 802.1Q trunk link transmits VLAN information through Ethernet.

QUESTION 28
Which term describes a spanning-tree network that has all switch ports in either the blocking or fowarding state?

A.    converged
B.    redundant
C.    provisioned
D.    spanned

Answer: A
Explanation:
Spanning Tree Protocol convergence (Layer 2 convergence) happens when bridges and switches have transitioned to either the forwarding or blocking state. When layer 2 is converged, root bridge is elected and all port roles (Root, Designated and Non-Designated) in all switches are selected.

QUESTION 29
What are the possible trunking modes for a switch port? (Choose three.)

A.    transparent
B.    auto
C.    on
D.    desirable
E.    client
F.    forwarding

Answer: BCD

QUESTION 30
Which two of these statements regarding RSTP are correct? (Choose two.)

A.    RSTP cannot operate with PVST+.
B.    RSTP defines new port roles.
C.    RSTP defines no new port states.
D.    RSTP is a proprietary implementation of IEEE 802.1D STP.
E.    RSTP is compatible with the original IEEE 802.1D STP.

Answer: BE
Explanation:
When network topology changes, rapid spanning tree protocol (IEEE802.1W, referred to as RSTP) will speed up significantly the speed to re-calculate spanning tree. RSTP not only defines the role of other ports: alternative port and backup port, but also defines status of 3 ports: discarding status, learning status, forwarding status.
RSTP is 802.1D standard evolution, not revolution. It retains most of the parameters, and makes no changes.

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QUESTION 11
Which two commands can be used to verify a trunk link configuration status on a given Cisco switch interface? (Choose two.)

A.    show interface trunk
B.    show interface interface
C.    show ip interface brief
D.    show interface vlan
E.    show interface switchport

Answer: AE

QUESTION 12
Which command enables RSTP on a switch?

A.    spanning-tree uplinkfast
B.    spanning-tree mode rapid-pvst
C.    spanning-tree backbonefast
D.    spanning-tree mode mst

Answer: B
Explanation:
Ethernet network is a shared environment so all devices have the right to access to the medium. If more than one device transmits simultaneously, the signals collide and can not reach the destination.
If a device detects another device is sending, it will wait for a specified amount of time before attempting to transmit.
When there is no traffic detected, a device will transmit its message. While this transmission is occurring, the device continues to listen for traffic or collisions on the LAN. After the message is sent, the device returns to its default listening mode.

QUESTION 13
What is the function of the command switchport trunk native vlan 999 on a Cisco Catalyst switch?

A.    It creates a VLAN 999 interface.
B.    It designates VLAN 999 for untagged traffic.
C.    It blocks VLAN 999 traffic from passing on the trunk.
D.    It designates VLAN 999 as the default for all unknown tagged traffic.

Answer: B
Explanation:
Configuring the Native VLAN for Untagged Traffic
A trunk port configured with 802.1Q tagging can receive both tagged and untagged traffic. By default, the switch forwards untagged traffic in the native VLAN configured for the port. The native VLAN is VLAN 1 by default.

QUESTION 14
Why will a switch never learn a broadcast address?

A.    Broadcasts only use network layer addressing.
B.    A broadcast frame is never forwarded by a switch.
C.    A broadcast address will never be the source address of a frame.
D.    Broadcast addresses use an incorrect format for the switching table.
E.    Broadcast frames are never sent to switches.

Answer: C
Explanation:
Switches dynamically learn MAC addresses based on the source MAC addresses that it sees, and since a broadcast is never the source, it will never learn the broadcast address.

QUESTION 15
Which two link protocols are used to carry multiple VLANs over a single link? (Choose two.)

A.    VTP
B.    802.1q
C.    IGP
D.    ISL
E.    802.3u

Answer: BD
Explanation:
Cisco switches can use two different encapsulation types for trunks, the industry standard 802.1q or the Cisco proprietary ISL. Generally, most network engineers prefer to use 802.1q since it is standards based and will interoperate with other vendors.

QUESTION 16
Assuming the default switch configuration, which VLAN range can be added, modified, and removed on a Cisco switch?

A.    1 through 1001
B.    2 through 1001
C.    1 through 1002
D.    2 through 1005

Answer: B
Explanation:
VLAN 1 is the default VLAN on Cisco switch. It always exists and can not be added, modified or removed.
VLANs 1002-1005 are default VLANs for FDDI & Token Ring and they can’t be deleted or used for Ethernet.

QUESTION 17
Which statement about VLAN operation on Cisco Catalyst switches is true?

A.    When a packet is received from an 802.1Q trunk, the VLAN ID can be determined from the source
MAC address and the MAC address table.
B.    Unknown unicast frames are retransmitted only to the ports that belong to the same VLAN.
C.    Broadcast and multicast frames are retransmitted to ports that are configured on different VLAN.
D.    Ports between switches should be configured in access mode so that VLANs can span across the ports.

Answer: B
Explanation:
Each VLAN resides in its own broadcast domain, so incoming frames with unknown destinations are only transmitted to ports that reside in the same VLAN as the incoming frame.

QUESTION 18
Which three statements about RSTP are true? (Choose three.)

A.    RSTP significantly reduces topology reconverging time after a link failure.
B.    RSTP expands the STP port roles by adding the alternate and backup roles.
C.    RSTP port states are blocking, discarding, learning, or forwarding.
D.    RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.
E.    RSTP also uses the STP proposal-agreement sequence.
F.    RSTP uses the same timer-based process as STP on point-to-point links.

Answer: ABD
Explanation:
One big disadvantage of STP is the low convergence which is very important in switched network. To overcome this problem, in 2001, the IEEE with document 802.1w introduced an evolution of the Spanning Tree Protocol: Rapid Spanning Tree Protocol (RSTP), which significantly reduces the convergence time after a topology change occurs in the network. While STP can take 30 to 50 seconds to transit from a blocking state to a forwarding state, RSTP is typically able to respond less than 10 seconds of a physical link failure.
RSTP works by adding an alternative port and a backup port compared to STP. These ports are allowed to immediately enter the forwarding state rather than passively wait for the network to converge.
RSTP bridge port roles:
* Root port – A forwarding port that is the closest to the root bridge in terms of path cost
* Designated port – A forwarding port for every LAN segment
* Alternate port – A best alternate path to the root bridge. This path is different than using the root port. The alternative port moves to the forwarding state if there is a failure on the designated port for the segment.
* Backup port – A backup/redundant path to a segment where another bridge port already connects. The backup port applies only when a single switch has two links to the same segment (collision domain). To have two links to the same collision domain, the switch must be attached to a hub.
* Disabled port – Not strictly part of STP, a network administrator can manually disable a port

QUESTION 19
At which layer of the OSI model is RSTP used to prevent loops?

A.    physical
B.    data link
C.    network
D.    transport

Answer: B
Explanation:
RSTP and STP operate on switches and are based on the exchange of Bridge Protocol Data Units (BPDUs) between switches. One of the most important fields in BPDUs is the Bridge Priority in which the MAC address is used to elect the Root Bridge -> RSTP operates at Layer 2 ?Data Link layer -> .

QUESTION 20
What does a Layer 2 switch use to decide where to forward a received frame?

A.    source MAC address
B.    source IP address
C.    source switch port
D.    destination IP address
E.    destination port address
F.    destination MAC address

Answer: F
Explanation:
When a frame is received, the switch looks at the destination hardware address and finds the interface if it is in its MAC address table. If the address is unknown, the frame is broadcast on all interfaces except the one it was received on.

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QUESTION 1
Which layer in the OSI reference model is responsible for determining the availability of the receiving program and checking to see if enough resources exist for that communication?

A.    transport
B.    network
C.    presentation
D.    session
E.    application

Answer: E
Explanation:
This question is to examine the OSI reference model. The Application layer is responsible for identifying and establishing the availability of the intended communication partner and determining whether sufficient resources for the intended communication exist.

QUESTION 2
Which of the following describes the roles of devices in a WAN? (Choose three.)

A.    A CSU/DSU terminates a digital local loop.
B.    A modem terminates a digital local loop.
C.    A CSU/DSU terminates an analog local loop.
D.    A modem terminates an analog local loop.
E.    A router is commonly considered a DTE device.
F.    A router is commonly considered a DCE device.

Answer: ADE
Explanation:
The idea behind a WAN is to be able to connect two DTE networks together through a DCE network. The network’s DCE device (includes CSU/DSU) provides clocking to the DTE-connected interface (the router’s serial interface).
A modem modulates outgoing digital signals from a computer or other digital device to analog signals for a conventional copper twisted pair telephone line and demodulates the incoming analog signal and converts it to a digital signal for the digital device. A CSU/DSU is used between two digital lines –
For more explanation of answer D, in telephony the local loop (also referred to as a subscriber line) is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the carrier or telecommunications service provider’s network. Therefore a modem terminates an analog local loop is correct.

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QUESTION 3
A network administrator is verifying the configuration of a newly installed host by establishing an FTP connection to a remote server. What is the highest layer of the protocol stack that the network administrator is using for this operation?

A.    application
B.    presentation
C.    session
D.    transport
E.    internet
F.    data link

Answer: A
Explanation:
FTP belongs to Application layer and it is also the highest layer of the OSI model.

QUESTION 4
A network interface port has collision detection and carrier sensing enabled on a shared twisted pair network. From this statement, what is known about the network interface port?

A.    This is a 10 Mb/s switch port.
B.    This is a 100 Mb/s switch port.
C.    This is an Ethernet port operating at half duplex.
D.    This is an Ethernet port operating at full duplex.
E.    This is a port on a network interface card in a PC.

Answer: C
Explanation:
Modern Ethernet networks built with switches and full-duplex connections no longer utilize CSMA/CD. CSMA/CD is only used in obsolete shared media Ethernet (which uses repeater or hub).

QUESTION 5
A receiving host computes the checksum on a frame and determines that the frame is damaged. The frame is then discarded. At which OSI layer did this happen?

A.    session
B.    transport
C.    network
D.    data link
E.    physical

Answer: D
Explanation:
The Data Link layer provides the physical transmission of the data and handles error notification, network topology, and flow control. The Data Link layer formats the message into pieces, each called a data frame, and adds a customized header containing the hardware destination and source address. Protocols Data Unit (PDU) on Datalink layer is called frame. According to this question the frame is damaged and discarded which will happen at the Data Link layer.

QUESTION 6
Which of the following correctly describe steps in the OSI data encapsulation process? (Choose two.)

A.    The transport layer divides a data stream into segments and may add reliability and flow control information.
B.    The data link layer adds physical source and destination addresses and an FCS to the segment.
C.    Packets are created when the network layer encapsulates a frame with source and destination host
addresses and protocol-related control information.
D.    Packets are created when the network layer adds Layer 3 addresses and control information to a segment.
E.    The presentation layer translates bits into voltages for transmission across the physical link.

Answer: AD
Explanation:
The Application Layer (Layer 7) refers to communications services to applications and is the interface between the network and the application. Examples include. Telnet, HTTP, FTP, Internet browsers, NFS, SMTP gateways, SNMP, X.400 mail, and FTAM.
The Presentation Layer (Layer 6) defining data formats, such as ASCII text, EBCDIC text, binary, BCD, and JPEG. Encryption also is defined as a presentation layer service. Examples include. JPEG, ASCII, EBCDIC, TIFF, GIF, PICT, encryption, MPEG, and MIDI.
The Session Layer (Layer 5) defines how to start, control, and end communication sessions. This includes the control and management of multiple bidirectional messages so that the application can be notified if only some of a series of messages are completed. This allows the presentation layer to have a seamless view of an incoming stream of data. The presentation layer can be presented with data if all flows occur in some cases. Examples include. RPC, SQL, NFS, NetBios names, AppleTalk ASP, and DECnet SCP
The Transport Layer (Layer 4) defines several functions, including the choice of protocols. The most important Layer 4 functions are error recovery and flow control. The transport layer may provide for retransmission, i.e., error recovery, and may use flow control to prevent unnecessary congestion by attempting to send data at a rate that the network can accommodate, or it might not, depending on the choice of protocols. Multiplexing of incoming data for different flows to applications on the same host is also performed. Reordering of the incoming data stream when packets arrive out of order is included. Examples include. TCP, UDP, and SPX.
The Network Layer (Layer 3) defines end-to-end delivery of packets and defines logical addressing to accomplish this. It also defines how routing works and how routes are learned; and how to fragment a packet into smaller packets to accommodate media with smaller maximum transmission unit sizes. Examples include. IP, IPX, AppleTalk DDP, and ICMP. Both IP and IPX define logical addressing, routing, the learning of routing information, and end-to-end delivery rules. The IP and IPX protocols most closely match the OSI network layer (Layer 3) and are called Layer 3 protocols because their functions most closely match OSI’s Layer 3.
The Data Link Layer (Layer 2) is concerned with getting data across one particular link or medium.
The data link protocols define delivery across an individual link. These protocols are necessarily concerned with the type of media in use. Examples includE. IEEE 802.3/802.2, HDLC, Frame Relay, PPP, FDDI, ATM, and IEEE 802.5/802.2.

QUESTION 7
Which three statements accurately describe Layer 2 Ethernet switches? (Choose three.)

A.    Spanning Tree Protocol allows switches to automatically share VLAN information.
B.    Establishing VLANs increases the number of broadcast domains.
C.    Switches that are configured with VLANs make forwarding decisions based on both Layer 2 and
Layer 3 address information.
D.    Microsegmentation decreases the number of collisions on the network.
E.    In a properly functioning network with redundant switched paths, each switched segment will contain
one root bridge with all its ports in the forwarding state. All other switches in that broadcast domain will
have only one root port.
F.    If a switch receives a frame for an unknown destination, it uses ARP to resolve the address.

Answer: BDE
Explanation:
Microsegmentation is a network design (functionality) where each workstation or device on a network gets its own dedicated segment (collision domain) to the switch. Each network device gets the full bandwidth of the segment and does not have to share the segment with other devices. Microsegmentation reduces and can even eliminate collisions because each segment is its own collision domain -> .
Note: Microsegmentation decreases the number of collisions but it increases the number of collision domains.

QUESTION 8
Where does routing occur within the DoD TCP/IP reference model?

A.    application
B.    internet
C.    network
D.    transport

Answer: B
Explanation:
The picture below shows the comparison between TCP/IP model & OSI model. Notice that the Internet Layer of TCP/IP is equivalent to the Network Layer which is responsible for routing decision.

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QUESTION 9
Refer to exhibit: Which destination addresses will be used by Host A to send data to Host C? (Choose two.)

A.    the IP address of Switch 1
B.    the MAC address of Switch 1
C.    the IP address of Host C
D.    the MAC address of Host C
E.    the IP address of the router’s E0 interface
F.    the MAC address of the router’s E0 interface

Answer: CF
Explanation:
While transferring data through many different networks, the source and destination IP addresses are not changed. Only the source and destination MAC addresses are changed. So in this case Host A will use the IP address of Host C and the MAC address of E0 interface to send data. When the router receives this data, it replaces the source MAC address with it own E1 interface’s MAC address and replaces the destination MAC address with Host C’s MAC address before sending to Host C .

QUESTION 10
For what two purposes does the Ethernet protocol use physical addresses? (Choose two.)

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A.    to uniquely identify devices at Layer 2
B.    to allow communication with devices on a different network
C.    to differentiate a Layer 2 frame from a Layer 3 packet
D.    to establish a priority system to determine which device gets to transmit first
E.    to allow communication between different devices on the same network
F.    to allow detection of a remote device when its physical address is unknown

Answer: AE
Explanation:
Physical addresses or MAC addresses are used to identify devices at layer 2.
MAC addresses are only used to communicate on the same network. To communicate on different network we have to use Layer 3 addresses (IP addresses) -> B is not correct.
Layer 2 frame and Layer 3 packet can be recognized via headers. Layer 3 packet also contains physical address ->
On Ethernet, each frame has the same priority to transmit by default -> All devices need a physical address to identify itself. If not, they can not communicate –>

 

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QUESTION 101
Refer to the exhibit. The Lakeside Company has the internetwork in the exhibit. The administrator would like to reduce the size of the routing table on the Central router. Which partial routing table entry in the Central router represents a route summary that represents the LANs in Phoenix but no additional subnets?

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