## Sunday, 6 May 2012

### CCNA Exam Certification

Refer to Exhibit.
The networks connected to router R2 have been summarized as a 192.168.176.0/21 route and sent to R1, Which two packet destination addresses will R1 forward to R2?  (Choose Two)

A.  192.168.194.160
B.  192.168.183.41
C.  192.168.159.2
D.  192.168.183.255
E.  192.168.179.4
F.  192.168.184.45

Convert 192.168.176.0 into Binary. Remember each octet has 8 bits.

192=
128   64   32   16   8   4   2   1

1       1    0      0    0   0   0   0

168=
128   64   32   16   8   4   2   1

1      0     1      0    1   0   0   0

176=
128   64   32   16   8   4   2   1

1      0     1     1     0   0   0   0

So the Binary break down of 192.168.176.0 is:
11000000.10101000.10110000.00000000

Then you need to break the /21 into a subnet then into Binary.
The Math  -  /21

Class C Subnet - 254 hosts - 255.255.255.0 /24

To figure out the /21 you know 255.255.255.0 is a /24 then you need to subtract 3 bits.

128  + 64 + 32 + 16 + 8 + 4  2  1
|         |       |       |      |
128 +  64 + 32 + 16 + 8 = 248

255.255.248.0 would then be a /21

Now break it into Binary
255.255.248.0 = 11111111.11111111.11111000

Now do the math between the IP and Subnet.

11000000.10101000.10110000.00000000  - IP
11111111.11111111.11111000.00000000  - Subnet

Turn it back into Decimal format:
192.168.183.255

So the answer is anything between 192.168.176.0 - 192.168.183.255 would be the answer.

B.  192.168.183.41
E.  192.168.179.4

==================================================================

Switch ports operating in which two roles will forward traffic according to the IEEE 802.1w standard? (Choose two.)

A. alternate
B. backup
C. designated
D. disabled
E. root

Root Port: The SwitchPort on each switch that has best root path cost to the root.

Designated Port: The switch port on the network segment which has best root path cost to the root.

Alternate Port: Which has the best alternate path to the Root Bridge other than the path that Root Port takes.This path is less desirable than path of Root Port.

Backup Port: Is rudundent path to a Network Segment where the switch port is connected.

Disabled: The Port is Disabled for the traffic to pass through it.
==================================================================

Refer to the exhibit. Which three statements correctly describe Network Device A? (Choose three.)

A. With a network wide mask of 255.255.255.128, each interface does not require an IP address.
B. With a network wide mask of 255.255.255.128, each interface does require an IP address on a unique IP subnet.
C. With a network wide mask of 255.255.255.0, must be a Layer 2 device for the PCs to communicate with each other.
D. With a network wide mask of 255.255.255.0, must be a Layer 3 device for the PCs to communicate with each other.
E. With a network wide mask of 255.255.254.0, each interface does not require an IP address.

Explanation:

If Subnet Mask is 255.255.255.128 the hosts vary from x.x.x.0 - x.x.x.127 & x.x.x.128- x.x.x.255,so the IP Addresses of 2 hosts fall in different subnets so each interface needs an IP an address so that they can communicate each other.

If Subnet Mask is 255.255.255.0 the 2 specified hosts fall in differnt subnets so they need a Layer 3 device to commicate.

If Subnet Mask is 255.255.254.0 the 2 specfied hosts are in same subnet so are in network address and can be accomidated in same Layer 2 domain and can communicate with each other directly using the Layer 2 adddress.
==================================================================

Refer to the exhibit. Which three statements are true about how router JAX will choose a path to the 10.1.3.0/24 network when different routing protocols are configured? (Choose three.)

A. By default, if RIPv2 is the routing protocol, only the path JAX-ORL will be installed into the routing table.
B. The equal cost paths JAX-CHI-ORL and JAX- NY-ORL will be installed in the routing table if RIPv2 is the routing protocol.

C. When EIGRP is the routing protocol, only the path JAX-ORL will be installed in the routing table by default.

D. When EIGRP is the routing protocol, the equal cost paths JAX-CHI-ORL, and JAX-NY-ORL will be installed in the routing table by default.

E. With EIGRP and OSPF both running on the network with their default configurations, the EIGRP paths will be installed in the routing table.

F. The OSPF paths will be installed in the routing table, if EIGRP and OSPF are both running on the network with their default configurations.

Explanation:

Only RIP protocol used Path selection is done by using HOP count as the metric,path with least HOP's will be taken as best path so option A.

Only EIGRP protocol used,EIGRP selects the best using a combinations of 5 metrics Bandwidth,Delay,Reliability,Load & MTU.If Metric is the same Load Balancing occurs
between the paths,Option D where 2 equal cost paths are taken.

If there are Mulitple Routing protocols used the Route with the Best AD is installed to the routing table.

OSPF and EIGRP are the 2 Routing protocols used and both have Route to a network then EIGRP path will be chosen to OSPF since lower AD. So Option E.
==================================================================

Which three statements are typical characteristics of VLAN arrangements? (Choose three.)

A. A new switch has no VLANs configured.
B. Connectivity between VLANs requires a Layer 3 device.
C. VLANs typically decrease the number of collision domains.
D. Each VLAN uses a separate address space.
E. A switch maintains a separate bridging table for each VLAN.
F. VLANs cannot span multiple switches.

Explanation:

VLAN are physical boundaries in logical way,every VLAN has its own subnet.To communicate between these subnets it has to go through a Layer3 device. An each VLAN acts as a seperate network has its own brodcast domain.So it maiantains its own bridging or MAC Address table.A frame in a VLAN stays in that VLAN,to go into differnet VLAN has to go through a Layer 3 device.
==================================================================

A network administrator changes the configuration register to 0x2142 and reboots the router. What are two results of making this change? (Choose two.)

A. The IOS image will be ignored.
B. The router will prompt to enter initial configuration mode.
C. The router will boot to ROM.
D. Any configuration entries in NVRAM will be ignored.
E. The configuration in flash memory will be booted.

Explanation:
The command to set the Configuration Register to 0x2142 is done in Global Configuration mode,It is done to ignore current startup sonfiguration and initally after reload the router will ask for initial configuration,

# show version command can be used to see the confreg set to.

router(config)#config-register 0x2142
==================================================================

Refer to the exhibit. Assume that the routing protocol referenced in each choice below is configured with its default settings and the given routing protocol is running on all the routers. Which two conditional statements accurately state the path that will be chosen between networks 10.1.0.0 and 10.3.2.0 for the routing protocol mentioned? (Choose two.)

A. If OSPF is the routing protocol, the path will be from R1 to R3 to R4 to R5.
B. If OSPF is the routing protocol, the path will be from R1 to R2 to R5.
C. If OSPF is the routing protocol, the path will be from R1 to R5.
D. If RIPv2 is the routing protocol, the path will be from R1 to R3 to R4 to R5.
E. If RIPv2 is the routing protocol, the path will be from R1 to R5.

Explanation:

OSPF metric for path selection is 100Mbps/(Bandwidth Of the Link) according to this rule lowst cost path is chosen

Option A: R1 to R3 to R4 to R5 = 100Mb/10 Base T + 100Mb/100 Base t + 100Mb/100 Base t
= 10+1+1 =12

Option B: R1 to R2 to R5 = 100Mb/T1 + 100 Mb/T1 =64.766 + 64.766 = 129.532

Option C: R1 to R5 = 100Mb/64k =1562

RIP will choose path with least HOP's so OPTION E
==================================================================

Which two values are used by Spanning Tree Protocol to elect a root bridge? (Choose two.)

A. amount of RAM
B. bridge priority
C. IOS version

Explanation:
ROOT Bridge in STP is like the reference point to that network. A ROOT bridge is elected using Bridge Priority and MAC Address. Generally Priority of switches is the default for all i.e. 32768.So the switch with Lowest MAC Address becomes Root Bridge of that network.
==================================================================

Refer to the exhibit. A network associate needs to configure the switches and router in the graphic so that the hosts in VLAN3 and VLAN4 can communicate with the enterprise server in VLAN2. Which two Ethernet segments would need to be configured as trunk links? (Choose two.)

A. A
B. B
C. C
D. D
E. E
F. F

Explanation:
Trunk links carry traffic of all VLAN's,Since paths C & F carry traffic of VLAN's 2,3,4. They should be configured with trunk  so that the traffic of all 3 VLAN's can run through it.
==================================================================

What are two advantages of Layer 2 Ethernet switches over hubs? (Choose two.)
A. decreasing the number of collision domains
B. filtering frames based on MAC addresses
C. allowing simultaneous frame transmissions
D. increasing the size of broadcast domains
E. increasing the maximum length of UTP cabling between devices

Explanation:
Hubs are layer 1 devices which flood out Traffic received on 1 port to all the ports on the Hub. Switches are uses ASIC hardware using which they learn the Source Mac-address of a frame and build MAC-Address Table using which frames are forwarded to destinations based on Mac-Addresses. So by this there are no collision domains. Since there are different collisions domains for each port simultaneous frame transmissions can occur.
==================================================================

Which two statements are true about the command ip route 172.16.3.0 255.255.255.0 192.168.2.4? (Choose two.)

A. It establishes a static route to the 172.16.3.0 network.
B. It establishes a static route to the 192.168.2.0 network.
C. It configures the router to send any traffic for an unknown destination to the 172.16.3.0 network.
D. It configures the router to send any traffic for an unknown destination out the interface with the address 192.168.2.4.
E. It uses the default administrative distance.
F. It is a route that would be used last if other routes to the same destination exist.

Explanation:
The IP Route command is used to write a static route to a specfied network via specified exit gateway or Interface,

[permanent | track number] [tag tag]

The question tells us that traffic to 172.16.3.0/24 network goes out through 192.168.2.4.

Since there is no administrative distance specified in the ip route command,the administrative distance is default.
==================================================================

What are two benefits of using VTP in a switching environment? (Choose two.)

A. It allows switches to read frame tags.
B. It allows ports to be assigned to VLANs automatically.
C. It maintains VLAN consistency across a switched network.
D. It allows frames from multiple VLANs to use a single interface.
E. It allows VLAN information to be automatically propagated throughout the switching environment.

Explanation:
VTP protocol has 3 modes Server,CLient & Transperent.There is only 1 server and all other switches in that environment are

Clients.Only server can create,modily and delete VLAN's so in VTP environment VLAN's are consistent across the network.The changes made on the Server are automatically propogated to all the clients through the TRUNK links established between the switches.
==================================================================

A company is installing IP phones. The phones and office computers connect to the same device. To ensure maximum throughput for the phone data, the company needs to make sure that the phone traffic is on a different network from that of the office computer data traffic. What is the best network device to which to directly connect the phones and computers, and what technology should be implemented on this device?
(Choose two.)

A. hub
B. router
C. switch
D. STP
E. subinterfaces
F. VLAN

Explanation:
Data and Voice need to be kept in seperate boundaries since normal data traffic is heavy and can crush Phone traffic which is real time so we need to introduce configuration and devices which support that like VLAN and SWITCH.

Which can segregate traffic without broadcasts or collisons? Cisco switches have Voice Vlans for this service.
==================================================================

Refer to the exhibit. The router has been configured with these commands:

hostname Gateway
interface FastEthernet 0/0
no shutdown
interface FastEthernet 0/1
no shutdown
interface Serial 0/0
no shutdown
ip route 0.0.0.0 0.0.0.0 64.100.0.1

What are the two results of this configuration? (Choose two.)

A. The default route should have a next hop address of 64.100.0.3.
B. Hosts on the LAN that is connected to FastEthernet 0/1 are using public IP addressing.
C. The address of the subnet segment with the WWW server will support seven more servers.
D. The addressing scheme allows users on the Internet to access the WWW server.
E. Hosts on the LAN that is connected to FastEthernet 0/1 will not be able to access the Internet without address translation.

Explanation:
Default route ponts to Next hop router 64.100.0.1 which connects the local network to the internet, since 198.133.219.14 is the interface address on router to which Web server is connected and no access list is blocking users to be access the web server. Since private IP's are not routeble on public internet they should be natted to access the Internet
==================================================================

Refer to the exhibit. Both switches are using a default configuration. Which two destination addresses will host 4 uses to send data to host 1? (Choose two.)

A. the IP address of host 1
B. the IP address of host 4
C. the MAC address of host 1
D. the MAC address of host 4
E. the MAC address of the Fa0/0 interface of the R1 router
F. the MAC address of the Fa0/1 interface of the R1 router

Explanation:

Option A: since it won’t send the data to its own IP Address, for the data to be sent to remote place Destination IP Address should be places in the header and Mac address of next layer 2 device needs to be the destination mac address. The layer 3 address show the directions for Layer 2 address to make the route to destination.
What are two reasons a network administrator would use CDP? (Choose two.)

A. to verify the type of cable interconnecting two devices
B. to determine the status of network services on a remote device
C. to obtain VLAN information from directly connected switches
D. to verify Layer 2 connectivity between two devices when Layer 3 fails
E. to obtain the IP address of a connected device in order to telnet to the device
F. to determine the status of the routing protocols between directly connected routers

Explanation: CDP
CDP announcements are sent every 60 seconds on interfaces that support Subnetwork Access Protocol (SNAP) headers, including Ethernet, Frame Relay and Asynchronous Transfer Mode (ATM).CDP works at layer 2 and all these adverts consist of infomation about all connected devices on the network like IP address,operating system etc.
==================================================================

Which two locations can be configured as a source for the IOS image in the boot system command? (Choose two.)

A. RAM
B. NVRAM
C. flash memory
D. HTTP server
E. TFTP server
F. Telnet server

Explanation:
Flash memory is storage on the Router where IOS can be dumped for the image to be loaded on to the router. TFTP Server uses UDP protocol and large enough to be configured as the source for IOS on the network generally used for upgrades. RAM is volatile, NVRAM is very small, HTTP server cannot share files & TELNET server is too slow.
==================================================================

A network administrator is explaining VTP configuration to a new technician. What should the network

A. A switch in the VTP client mode cannot update its local VLAN database.
B. A trunk link must be configured between the switches to forward VTP updates.
C. A switch in the VTP server mode can update a switch in the VTP transparent mode.
D. A switch in the VTP transparent mode will forward updates that it receives to other switches.
E. A switch in the VTP server mode only updates switches in the VTP client mode that have a higher VTP revision number.
F. A switch in the VTP server mode will update switches in the VTP client mode regardless of the configured VTP domain membership.

Explanation:

Switches configured with VTP may be in 3 modes.Client,Server & Transperent.Client does not save updates recieved in its VLAN database or in NVRAM,since client does not create,modify or delete VLAN's it only uses them.If VTP updates are to be forwarded between switches the link has to be configured as Trunk since only the trunk link carries information about the VLAN's. A switch in transparent mode will not change its Database or use information from other switches but will send information to other switches.
==================================================================

Refer to the exhibit. Which two statements are true about the loopback address that is configured on RouterB? (Choose two.)

A. It ensures that data will be forwarded by RouterB.
B. It provides stability for the OSPF process on RouterB.
C. It specifies that the router ID for RouterB should be 10.0.0.1.
D. It decreases the metric for routes that are advertised from RouterB.
E. It indicates that RouterB should be elected the DR for the LAN.

Explanation:
Loopback address gives stability to OSPF process on RouterB as compared to physical interface address as LOOPBACK interface never goes down which is not same with physical interface. In OSPF Router ID is the Highest IP address on that Router or  Loopback address or Manually Hard-Coded. Since RouterB has loopback address as 10.0.0.1 and no manual Router ID, Loopback is the Router ID.
==================================================================

Refer to the exhibit. Which two statements are true about interVLAN routing in the topology that is shown in the exhibit? (Choose two.)

A. Host E and host F use the same IP gateway address.
B. Router1 and Switch2 should be connected via a crossover cable.
C. Router1 will not play a role in communications between host A and host D.
D. The FastEthernet 0/0 interface on Router1 must be configured with subinterfaces.
E. Router1 needs more LAN interfaces to accommodate the VLANs that are shown in the exhibit.
F. The FastEthernet 0/0 interface on Router1 and Switch2 trunk ports must be configured using the same encapsulation type.

Explanation:
The router has switch connected to VLAN1 and VLAN 2, since different VLAN's have different IP subnets which need to be connected to different interfaces. In this exhibit different Physical Interfaces are not possible so Sub-Interfaces are to be configured. Since Router1 and Switch2 are connected through Trunk the encapsulation has to be same on the both ends to Trunk to be established and data of different VLAN's to pass through it.
==================================================================

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

Explanation:

The version of IOS bring you new features and additional enhancements to your needs, as the additions increase the need for additional RAM is needed for the new IOS to run, Flash memory is where IOS is dumped to be loaded by router bootstrap to run the IOS. Last but not the least the version of IOS has to be checked before upgrading new IOS as to see the current version, Hardware compatibility with new IOS and other details of the hardware to which IOS to be loaded.
==================================================================

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#### 1 comment:

1. That's really amazing and difficult one also like he router has switch connected to VLAN1 and VLAN 2, since different VLAN's have different IP subnets which need to be connected to different interfaces.But ver different from CISSP