Thursday, 11 April 2013

CCNA interview questions part-2

51. Which addresses are INCORRECTLY paired with their class?
* 128 to 191, Class B
* 192 to 223 Class B
* 128 to 191, Class C
* 192 to 223, Class C
Correct answer: B & C
Address classes are: 1 to 126, Class A; 128 to 191, Class B, 192 to 223, Class C; 224 to 239, Class D; and
52. to 255, Class E. The first octet rule states that the class of an address can be determined by the numerical value of the first octet.

53. Which addresses are INCORRECTLY paired with their class?
* 1 to 126, Class A
* 128 to 191, Class A
* 1 to 126, Class B
* 128 to 191, Class B
Correct answer: B & C.
Address classes are: 1 to 126, Class A; 128 to 191, Class B, 192 to 223, Class C; 224 to 239, Class D; and
54. to 255, Class E. The first octet rule states that the class of an address can be determined by the numerical value of the first octet.
55. Which addresses are INCORRECTLY paired with their class?
* 240 – 255, Class D
* 240 – 255, Class E
* 224 – 239, Class D
* 224 – 239, Class E
Correct answer: A & D
Address classes are: 1 to 126, Class A; 128 to 191, Class B, 192 to 223, Class C; 224 to 239, Class D; and 240 to 255, Class E.
56. Which IP Address Class is INCORRECTLY paired with its range of network numbers?
* Class A addresses include 192.0.0.0 through 223.255.255.0
* Class A addresses include 1.0.0.0 through 126.0.0.0
* Class B addresses include 128.0.0.0 through 191.255.0.0
* Class C addresses include 192.0.0.0 through 223.255.255.0
* Class D addresses include 224.0.0.0 through 239.255.255.0
Correct answer: A
Class A addresses include 1.0.0.0 through 126.0.0.0
Class B addresses include 128.0.0.0 through 191.255.0.0
Class C addresses include 192.0.0.0 through 223.255.255.0
Class D addresses include 224.0.0.0 through 239.255.255.0
57. Which IP Address Class can have 16 million subnets but support 254 hosts?
* Class C
* Class A
* Class B
* Class D
Correct answer: A
Possible Subnets IP Address Class Possible Hosts
58. A 16M.
64K B 64K
16M C 254
59. Which IP Address Class can have 64,000 subnets with 64,000 hosts per subnet?
* Class B
* Class A
* Class C
* Class D
Correct answer: A
IP Address Class Possible Subnets Possible Hosts
60. A 16M
64K B 64K
16M C 254
61. There are two processes to pair MAC address with IP addresses. Which process finds an IP address from a MAC address?
* RARP
* ARP
* RIP
* IGRP
Correct answer: A
ARP (Address Resolution Protocol) maps an IP address to the MAC address, RARP (Reverse Address Resolution Protocol) maps the MAC address to the IP address. ARP and RARP work at the internet layer of the Internet Model or the network layer of the OSI model.
62. When the router runs out of buffer space, this is called ________.
* Source Quench
* Redirect
* Information Request
* Low Memory
Correct answer: A
Source quench is the process where the destination router, or end internetworking device will “quench” the date from the “source”, or the source router. This usually happens when the destination router runs out of buffer space to process packets.
63. Which protocol carries messages such as destination Unreachable, Time Exceeded, Parameter Problem, Source Quench, Redirect, Echo, Echo Reply, Timestamp, Information Request, Information Reply, Address Request, and Address Reply?
* ICMP
* UDP
* TCP
* TFTP
* FTP
Correct answer: A
ICMP (Internet Control Message Protocol) is a network layer internet protocol described in RFC # 792. ICMP reports IP packet information such as destination Unreachable, Time Exceeded, Parameter Problem, Source Quench, Redirect, Echo, Echo Reply, Timestamp, Information Request, Information Reply, Address Request, and Address Reply.
64. Two of the protocols that can be carried in the Protocol field of an IP packet are?
* TCP
* UDP
* FTP
* TFTP
Correct answer: A & B
The following are the fields in an IP segment,
their length, and their definitions:
VERS (Version number – 16 bits)
HLEN (Number of 32-bit words in the header – 4 bits)
Type of Server (How the datagram should be handled – 32 bits)
Total Length (Total length of header and data – 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet – 6 bits)
TTL (Time-To-Live – 6 bits)
Protocol (Upperlayer protocol sending the datagram – 16 bits)
Header Checksum )Integrity check on the header – 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others – 4 bits)
Data (4 bits).
65. Where would network testing be included in an IP packet?
* IP Options field
* Identification field
* Type of Service field
* Reservation field
Correct answer: A
The following are the fields in an IP segment, their length, and their definitions:
VERS (Version number – 16 bits)
HLEN (Number of 32-bit words in the header – 4 bits)
Type of Server (How the datagram should be handled – 32 bits)
Total Length (Total length of header and data – 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet – 6 bits)
TTL (Time-To-Live – 6 bits)
Protocol (Upperlayer protocol sending the datagram – 16 bits)
Header Checksum )Integrity check on the header – 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others – 4 bits)
Data (4 bits).
66. What field tells the Internet layer how to handle an IP packet?
* Type of Service
* Identification
* Flags
* Frag Offset
Correct answer: A
The following are the fields in an IP segment, their length, and their definitions:
VERS (Version number – 16 bits)
HLEN (Number of 32-bit words in the header – 4 bits)
Type of Server (How the datagram should be handled – 32 bits)
Total Length (Total length of header and data – 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet – 6 bits)
TTL (Time-To-Live – 6 bits)
Protocol (Upperlayer protocol sending the datagram – 16 bits)
Header Checksum )Integrity check on the header – 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others – 4 bits) Data (4 bits).
67. Which fields of an IP packet provide for fragmentation of datagrams to allow differing MTUs in the internet?
* Identification
* Flags
* Frag Offset
* Type of Service
* Total Length
Correct answer: A, B & C
The following are the fields in an IP segment, their length, and their definitions:
VERS (Version number – 16 bits)
HLEN (Number of 32-bit words in the header – 4 bits)
Type of Server (How the datagram should be handled – 32 bits)
Total Length (Total length of header and data – 32 bits)
Identification (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Flags (Provide fragmentation of datagrams to allow different MTUs in the internet – 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow different MTUs in the internet – 6 bits)
TTL (Time-To-Live – 6 bits)
Protocol (Upperlayer protocol sending the datagram – 16 bits)
Header Checksum )Integrity check on the header – 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others – 4 bits)
Data (4 bits).
68. Which processes does TCP, but not UDP, use?
* Windowing
* Acknowledgements
* Source Port
* Destination Port
Correct answer: A & B
UDP (User Datagram Protocol) does not use sequence or acknowledgement fields in transmission.
UDP is a connectionless and unreliable protocol, since there is no delivery checking mechanism in the UDP data format.
69. What is the UDP datagram format?
* Source Port – 16 bits, Destination Port – 16 bits, Length – 16 Bits, Checksum – 16 bits, Data
* Destination Port – 16 bits, Source Port – 16 bits, Length – 16 Bits, Checksum – 16 bits, Data
* Source Port – 16 bits, Destination Port – 16 bits, Checksum – 16 Bits, Length – 16 bits, Data
* Source Port – 8 bits, Destination Port – 8 bits, Length -8 Bits, Checksum – 8 bits, Data
Correct answer: A
The UDP format for a segment is as follows:
Source Port 16 bits
Destination Port 16 bits
Length 16 bits
Checksum 16 bits
Data xx bits
70. What is the function of DDR on Cisco routers?
* DDR is dial–on-demand routing. It provides a continuous LAN only connection.
* DDR is dial-on-demand routing. It provides routing for high volume traffic.
* DDR is dial–on-demand routing. It provides a continuous WAN connection.
* DDR is dial-on-demand routing. It provides routing for low volume and periodic traffic.
Correct answer: D
DDR is dial-on-demand routing. It provides routing for low volume and periodic traffic. It initiates a call to a remote site when there is traffic to transmit.
71. What are the two types of access lists that can be configured on a Cisco router?
* Standard
* Extended
* Filtering
* Packet
Correct answer: A & B
The access lists are standard and extended. Standard access lists for IP check the source address of packets that could be routed. Extended access lists can check the source and destination packet plus check for specific protocols, port numbers, etc.
72. When using access lists, what does a Cisco router check first?
* To see if the packet is routable or bridgeable
* The destination address
* The source address
* The packet contents
Correct answer: A
The first thing checked is to see if the packet is routable or bridgeable. If it is not, the packet will be dropped.
73. How many access lists are allowed per interface?
* One per port, per protocol
* Two per port, per protocol
* Unlimited
* Router interface +1 per port.
Correct answer: A
Only one access list is allowed per interface. An access list must have conditions that test true for all packets that use the access list.
74. What do the following commands accomplish?
access-list 1 deny 172.16.4.0 0.0.0.255
access-list 1 permit any interface ethernet 0
IP access-group 1 out
* This will block traffic from subnet 172.16.4.0 and allow all other traffic.
* This will allow traffic from subnet 172.16.4.0 and block all other traffic.
* All traffic is allowed.
* All traffic is blocked.
Correct answer: A
This will block traffic from subnet 172.16.4.0 and allow all other traffic. The first statement “access-list 1 deny 172.16.4.0 0.0.0.255″ will deny access to the subnet 172.16.4.0.
75. What do the following statements in an extended access list accomplish?
access-list 101 deny TCP 172.16.4.0 0.0.0.255 172.16.3.0 0.0.0.255 eq 21
access-list 101 deny TCP 172.16.4.0 0.0.0.255 172.16.3.0 0.0.0.255 eq 20
access-list 101 permit TCP 172.16.4.0 0.0.0.255 0.0.0.0 255.255.255.255
* This will block ftp traffic.
* This will block http traffic.
* This will permit ftp traffic.
* This will permit tftp traffic.
Correct answer: A
This will block ftp traffic since ftp uses ports 20 and 21.
76. Access lists are numbered. Which of the following ranges could be used for an IP access list?
* 600 – 699
* 100 – 199
* 1 – 99
* 800 – 899
* 1000 – 1099
Correct answer: wer: B & C
AppleTalk access lists use numbers in the 600 – 699 range. IP uses 1 – 99 for standard access lists or 100-199 for extended access lists. IPX uses 800 – 899 or 900 – 999 for extended access lists. IPX SAP filters use 1000 – 1099.
77. Cisco routers use wildcard masking to identify how to check or ignore corresponding IP address bits. What does setting a wildcard mask bit to 0 cause the router to do?
* It tells the router to check the corresponding bit value.
* It tells the router to ignore the corresponding bit value.
* It tells the router to check its alternate routing list.
* It tells the router to use its primary routing list.
Correct answer: A
It tells the router to check the corresponding bit value.
78. You are a system administrator and you want to deny access to a group of computers with addresses 172.30.16.0 to 172.30.31.0. Which wildcard mask would you use?
* 0.0.15.255
* 0.0.255.255
* 0.0.31.255
* 0.0.127.255
* 0.0.255.255
Correct answer: A
0.0.15.255 will check the last 13 bits of an address so that computers 172.30.16.0 to 172.30.31.0 will be denied access. 0.0.31.255 would check the last 6 binary digits and deny access to addresses 172.30.32.0 to 172.30.63.0. 0.0.127.255 would check the last 7 binary digits and deny access to addresses 172.30.64.0 to 172.30.127.0. 0.0.255.255 would deny 172.30.0.0 to 172.30.254.0. If you write decimal 15 in binary, you have 0001111, the 1’s tell the router to ignore address with these bits set; 0’s tell the router to check the bits. The third octet for 172.30.16.0 is 00010000. The third octet for 172.30.31.0 would be 00011111. So, traffic from these addresses would be denied.
79. In order to limit the quantity of numbers that a system administrator has to enter, Cisco can use which abbreviation to indicate 0.0.0.0?
* host
* any
* all
* include
Correct answer: A
Cisco uses host to specify 0.0.0.0. This tells the router to check all. Cisco uses any to specify 255.255.255.255. This tells the router to ignore all and permit any address to use an access list test.
80. What do the following commands accomplish?
access-list 1 permit 172.16.0.0 0.0.255.255
interface ethernet 0
IP access-group 1 out
interface ethernet 1
IP access-group 1 out
* Only traffic from the source network 172.16.0.0 will be blocked.
* Only traffic from the source network 172.16.0.0 will be forwarded. Non-172.16.0.0 network traffic is blocked.
* Non-172.16.0.0 traffic will be forwarded.
* All traffic will be forwarded.
Correct answer: B
Only traffic from the source network 172.16.0.0 will be forwarded. Non-172.16.0.0 network traffic is blocked. The wildcard mask 0.0.255.255 tells the router to check the first 2 octets and to ignore the last 2 octets.
81. When using access lists, it is important where those access lists are placed. Which statement best describes access list placement?
* Put standard access lists as near the destination as possible. Put extended access lists as close to the source as possible.
* Put extended access lists as near the destination as possible. Put standard access lists as close to the source as possible.
* It isn’t import where access lists are placed since the router will read and cache the whole list.
* Put access lists as close to corporate headquarters as possible.
Correct answer: A
Put standard access lists as near the destination as possible. Put extended access lists as close to the source as possible. Standard access lists don’t specify the destination address.
82. As the system administrator, you enter the following commands at the command prompt:
ipx routing
access-list 800 permit 2b 4d
int e0
ipx network 4d
ipx access-group 800 out
int e1
ipx network 2b
int e2
ipx network 3c
What did these command accomplish?
* Traffic from network 4c destined for network 4d will be forwarded out Ethernet0.
* Traffic from network 3c destined for network 4d will be forwarded out Ethernet0.
* Traffic from network 2b destined for network 4d will be forwarded out Ethernet0.
* Traffic from network 4d destined for network 2d will be forwarded out Ethernet0.
Correct answer: C
Traffic from network 2b destined for network 4d will be forwarded out Ethernet0. The other interfaces E1 and E2 are not subject to the access list since they lack the access group statement to link them to access list 800.
83. The following commands were entered at the command prompt of a Cisco router. What do they accomplish?
access-list 1000 deny 9e.1234.5678.1212 4
access-list 1000 permit -1
interface ethernet 0
ipx network 9e
interface ethernet 1
ipx network 4a
interface serial 0
ipx network 1
ipx output-sap-filter 1000
* File server advertisements from server 9e.1234.5678.1212 will not be forwarded on interface S0.
* All other SAP services, other than file server, from any source will be forwarded on S0.
* All other SAP services, other than print server, from any source will be forwarded on S0.
* Print server advertisements from server 9e.1234.5678.1212 will not be forwarded on interface S0.
Correct answer: A & B
File server advertisements from server 9e.1234.5678.1212 will not be forwarded on interface S0. All other SAP services, other than file server, from any source will be forwarded on S0.
84. You receive “input filter list is 800 and output filter list is 801″ as part of the output from a show interfaces command. What kind of traffic are you filtering?
* IPX/SPX
* TCP/IP
* LocalTalk
* DDR
Correct answer: A
Because the access list is numbered in the 800 range, you are filtering IPX/SPX traffic.
85. Which service uses telephone control messages and signals between the transfer points along the way to the called destination?
* Signaling System 7 (SS7)
* Time-division Multiplexing (TDM)
* X.25
* Frame relay
Correct answer: A
Signaling System 7 (SS7) uses telephone control messages and signals between the transfer points along the way to the called destination. Time-division Multiplexing (TDM) has information from multiple sources and allocates bandwidth on a single media. Circuit switching uses signaling to determine the call route, which is a dedicated path between the sender and the receiver. Basic telephone service and Integrated Services Digital Network (ISDN) use TDM circuits. X.25 and Frame Relay services have information contained in packets or frames to share non-dedicated bandwidth. X.25 avoids delays for call setup. Frame Relay uses permanent virtual circuits (PVCs).
86. Which service takes information from multiple sources and allocates bandwidth on a single media?
* Time-division Multiplexing (TDM)
* Signaling System 7 (SS7)
* X.25
* Frame relay
Correct answer: A
87. Which three devices can be used to convert the user data from the DTE into a form acceptable to the WAN service’s facility?
* Modem
* CSU/DSU
* TA/NT1
* CO
* SS7
Correct answer: A, B & C
A modem, CSU/DSU (Channel Service Unit/Data Service Unit), or TA/NT1 (Terminal Adapter/Network Termination 1) can be used to convert the user data from the DTE into a form acceptable to the WAN service’s facility.
88. What is the juncture at which the CPE ends and the local loop portion of the service begins?
* Demarc
* CO
* Local loop
* Last-mile
Correct answer: A
The demarcation or demarc is the juncture at which the CPE ends and the local loop portion of the service begins. The CO (Central Office) is the nearest point of presence for the provider’s WAN service. The local loop or “last-mile” is the cabling that extends from the demarc into the WAN service provider’s central office.
89. You can access three forms of WAN services with Cisco routers. Select the three forms:
* Switched or relayed services
* Interface front end to IBM enterprise data center computers
* Using protocols that connect peer-to-peer devices like HDLC or PPP encapsulation.
* IPX/SPX
* NetBEUI
Correct answer: A, B & C
You can access three forms of WAN services with Cisco routers. Switched or relayed services include X.25, Frame Relay, and ISDN. An interface front end to IBM enterprise data center computers includes SDLC. And, you can access the services of WAN providers using protocols that connect peer devices such as HDLC and PPP encapsulation. IPX/SPX and NetBEUI are LAN protocols.
90. Select the fields for the Cisco HDLC protocol:
* Flag, Address, Control
* Flag, Address, Control, Protocol, LCP (Code, Identifier, Length, Data), FCS, Flag
* Flag, Address, Control, Data, FCS, Flag
* Flag, Address, Control, Proprietary, Data, FCS, Flag
Correct answer: D
The Cisco HDLC frame format is Flag, Address, Control Proprietary, Data, FCS, Flag. The PPP frame format is Flag, Address, Control, Protocol, LCP (Code, Identifier, Length, Data), FCS, Flag. The SDLC and LAPB format is Flag, Address, Control, Data, FCS, Flag.
85: Select the physical interfaces that PPP can be configured on a Cisco router:
* Asynchronous serial
* HSSI
* ISDN
* Synchronous serial
Correct answer: A, B, C & D
All four of them can carry PPP traffic. HSSI is High Speed Serial Interface.
91. Select the correct statements about PPP and SLIP for WAN communications?
* PPP uses its Network Control Programs (NCPs) component to encapsulate multiple protocols.
* PPP can only transport TCP/IP
* SLIP can only transport TCP/IP.
* SLIP uses its Network Control Programs (NCPs) component to encapsulate multiple protocols.
Correct answer: A & C
87a Which protocol for PPP LCP (Link Control Protocol) performs a challenge handshake?
* CHAP
* PAP
* UDP
* IPX
Correct answer: A
87b Which form of PPP error detection on Cisco routers monitors data dropped on a link?
* Quality
* Magic Number
* Error Monitor
* Droplink
Correct answer: A

The Quality protocol monitors data dropped on a link. Magic Number avoids frame looping.
92. Which protocol for PPP provides load balancing across multiple links?
* Multilink Protocol (MP)
* Quality
* Magic Number
* Stacker
* Predictor
Correct answer: A
93. As the system administrator, you type “ppp authentication chap pap secret”. Which authentication method is used first in setting up a session?
* secret
* PAP
* CHAP
* PPP/SLIP
Correct answer: C
94. Select the compression protocols for PPP?
* Stac
* Predictor
* Quality
* Magic Number
Correct answer: A & B
95. What are the three phases of PPP session establishment?
* Link establishment phase
* Authentication phase
* Network layer protocol phase
* Handshake phase
* Dial-in phase
Correct answer: A, B & C
96. What is the default IPX Ethernet encapsulation?
* SNAP
* Arpa
* 802.2
* Novell-Ether
* SAP
Correct answer: D
97. What must be true for two Routers running IGRP to communicate their routes?
* Same autonomous system number
* Connected using Ethernet only
* Use composite metric
D)Configured for PPP
Correct answer: A
98. The following is partial output from a routing table, identify the 2 numbers in the square brackets; ‘192.168.10.0 [100/1300] via 10.1.0.1, 00:00:23, Ethernet1′
* 100 = metric, 1300 = administrative distance
* 100 = administrative distance, 1300 = hop count
* 100 = administrative distance, 1300 = metric
* 100 = hop count, 1300 = metric
Correct answer: C
99. Identify 3 methods used to prevent routing loops?
* Split horizon
* Holddown timers
* Poison reverse
* SPF algorithm
* LSP’s
Correct answer: A B C
100. Which statement is true regarding full duplex?
* Allows for transmission and receiving of data simultaneously
* Only works in a multipoint configuration
* Does not affect the bandwidth
* Allows for transmission and receiving of data but not a the same time
Correct answer: A
Full duplex is just the opposite of half duplex. It handles traffic in both directions simultaneously.

CCNA INTERVIEW QUESTIONS and Answers

Q1. Which of the following is Class C IP address?
A. 10.10.14.118
B. 135.23.112.57
C. 191.200.199.199
D. 204.67.118.54
Correct Answer: D.
Explanation:
IP addresses are written using decimal numbers separated by decimal points. This is called dotted decimal notation of expressing IP addresses.
Q2. You have an IP of 156.233.42.56 with a subnet mask of 7 bits. How many hosts and subnets are possible?
A. 126 hosts and 510 subnets
B. 128 subnets and 512 hosts
C. 510 hosts and 126 subnets
D. 512 subnets and 128 hosts
Correct answer: C
Explanation:
Class B network has the form N.N.H.H, the default subnet mask is 16 bits long.
There is additional 7 bits to the default subnet mask. The total number of bits in subnet are 16+7 = 23.
This leaves us with 32-23 =9 bits for assigning to hosts.
7 bits of subnet mask corresponds to (2^7-2)=128-2 = 126 subnets.
9 bits belonging to host addresses correspond to (2^9-2)=512-2 = 510 hosts.

Q3. Two sub layers of OSI Data Link layer are which of the following? [Select 2].
A. Logical Link Control
B. Data Link Control
C. Media Access Control
D. Physical Layer Control
Correct answer: A,C
Q4. Match the following:
A. Repeaters 1. Data Link Layer
B. Bridges 2. Network Layer
C. Routers 3. Physical Layer
Select the best combination:
A. A —>2, B—>3, C—>1
B. A—>3, B—->1, C—->2
C. A—>3,B—–>2, C—->1
D. A—->1, B—->2, C—->3
Correct answer: B
Q5. Which of the following are session layer standards? [Select 2].
A. NFS
B. SQL
C. JPG
D. MIDI
Correct answer: A,B
Q6. Match the corresponding layers of ISO and DoD models?
DoD Model <———> ISO OSI Model
A. Process/Application 1. Application
B. Host-to-Host 2. Presentation
C. Internet 3. Session
D. Network Access 4. Transport
5. Network
6. Data Link
7. Physical
Choose best choice:
A. A->1+2; B->3+4; C->5; D->6+7
B. A->1+2+3; B->4; C->5; D->6+7
C. A->1+2+3; B->4; C->5+6; D->7
D. A->1+2+3; B->4+5; C->6; D->7
Correct answer: B
Q7. What is the command used to add a banner to a Cisco router configuration?
A. add banner
B. banner motd #
C. motd banner #
D. add banner #
Correct answer: B
Q8. What is the default administrative distance for RIP?
A. 100
B. 120
C. 0
D. 200
Correct answer: B
Q9. The Cisco Catalyst 1900 switches support which three LAN switch types? [Select 3].
A. Store-and-Forward
B. FragmentFree
C. InstaSwitch
D. FastForward
Correct answer: A,B,D
Q10. Which is true regarding VLANs?
A. VLAN technology uses VLAN switches (layer 2) which is a substitute for routing technology which uses routers.
B. A VLAN has same collision domain
C. A VLAN has same broadcast domain
D. VLANs are less secure with respect to simple switch or Hub networks.
Correct answer: C
Q11. Your internet work consists entirely of Cisco devices. You have given a command “show cdp neighbors”. In the response, you get “S” under the head “Capability”. What does the letter “S” mean?
A. It means “Source Route Bridge”
B. It means “Host”
C. It means “Switch”
D. It means “Static”
Correct answer: C
Q12. You want to verify the encapsulation type being used at Data Link layer for interface s0. Which command can you use?
A. Sh ip protocol
B. sh int s0
C. sh ip interface
D. sh processes
Correct answer: B
Q13. You want to run 802.2 frame type on your Ethernet interface. Which encapsulation type has to be chosen?
A. Ethernet_II
B. 802.2
C. SAP
D. SNAP
Answer is C
Q14. What does -1 signify in an extended IPX access list?
A. permit this host
B. deny this host
C. permit only this subnet
D. any host or any network
Correct answer: D
Q15. Which command sequence will allow only traffic from network 185.64.0.0 to enter interface s0?
A. access-list 25 permit 185.64.0.0 255.255.0.0
int s0 ; ip access-list 25 out
B. access-list 25 permit 185.64.0.0 255.255.0.0
int s0 ; ip access-group 25 out
C. access-list 25 permit 185.64.0.0 0.0.255.255
int s0 ; ip access-list 25 in
D. access-list 25 permit 185.64.0.0 0.0.255.255
int s0 ; ip access-group 25 in
Correct answer: D
Q16. Which of the following are reference points relevant to ISDN? [Select 2].
A. T
B. U
C. V
D. X
Correct answer: A,B
Q17. Which is true about VLAN Trunk Protocol? [Select 2].
A. VTP is statically configured and no built in intelligence is available.
B. VTP provides intelligence for configuring switches across the network.
C. VTP is not designed to distribute information across the switch fabric.
D. VTP is designed to distribute information across the switch fabric.
Correct answer: B, D
Q18. Which of the following is a term associated with WAN terminology / is a WAN device? [Select all that apply].
A. Demarc
B. DSU/CSU
C. Modem
D. CPE
Correct answer: A, B, C, D
Q19. Which of the following can be used to view the previous command you entered into a Cisco router? [Select 2].
A. CTRL+F1
B. The Down Arrow
C. The Up Arrow
D. CTRL + P
Correct answer: C, D
Q20. What is true about static VLANs? [Choose the best answer].
A. The VLAN is configured by a TFTP server.
B. It automatically notify a new network user.
C. The administrator assigns VLAN by port.
D. Static VLAN are more appropriate when the switch fabric becomes more complex.
Correct answer: C

Wednesday, 10 April 2013

DDR4 – Advantages of Migrating from DDR3

DDR4 is the next evolution in DRAM, bringing even higher performance and more robust control features while improving energy economy for enterprise, micro-server, tablet, and ultrathin client applications. The following table compares some of the key feature differences between DDR3 and DDR4.

Feature/Option	DDR3	DDR4	DDR4 Advantage
Voltage (core and I/O)	1.5V	1.2V	Reduces memory power demand
V_REF inputs	2 – DQs and CMD/ADDR	1 – CMD/ADDR	V_REFDQ now internal
Low voltage standard	Yes (DDR3L at 1.35V)	Anticipated (likely 1.05V)	Memory power reductions
Data rate (Mb/s)	800, 1066, 1333, 1600, 1866, 2133	1600, 1866, 2133, 2400, 2667, 3200	Migration to higher‐speed I/O
Densities	512Mb–8Gb	2Gb–16Gb	Better enablement for large-capacity memory subsystems
Internal banks	8	16	More banks
Bank groups (BG)	0	4	Faster burst accesses
^tCK – DLL enabled	300 MHz to 800 MHz	667 MHz to 1.6 GHz	Higher data rates
^tCK – DLL disabled	10 MHz to 125 MHz (optional)	Undefined to 125 MHz	DLL-off now fully supported
Read latency	AL + CL	AL + CL	Expanded values
Write latency	AL + CWL	AL + CWL	Expanded values
DQ driver (ALT)	40Ω	48Ω	Optimized for PtP (point-to-point) applications
DQ bus	SSTL15	POD12	Mitigate I/O noise and power
R_TT values (in Ω)	120, 60, 40, 30, 20	240, 120, 80, 60, 48, 40, 34	Support higher data rates
R_TT not allowed	READ bursts	Disables during READ bursts	Ease-of-use
ODT modes	Nominal, dynamic	Nominal, dynamic, park	Additional control mode; supports OTF value change
ODT control	ODT signaling required	ODT signaling not required	Ease of ODT control, allows non-ODT routing on PtP applications
Multipurpose register (MPR)	Four registers – 1 defined, 3 RFU	Four registers – 3 defined, 1 RFU	Provides additional specialty readout

Tuesday, 9 April 2013

IP address classes

Class	1^st Octet Decimal Range	1^st Octet High Order Bits	Network/Host ID (N=Network, H=Host)	Default Subnet Mask	Number of Networks	Hosts per Network (Usable Addresses)
A	1 – 126*	0	N.H.H.H	255.0.0.0	126 (2⁷ – 2)	16,777,214 (2²⁴ – 2)
B	128 – 191	10	N.N.H.H	255.255.0.0	16,382 (2¹⁴ – 2)	65,534 (2¹⁶ – 2)
C	192 – 223	110	N.N.N.H	255.255.255.0	2,097,150 (2²¹ – 2)	254 (2⁸ – 2)
D	224 – 239	1110	Reserved for Multicasting
E	240 – 254	1111	Experimental; used for research

Note: Class A addresses 127.0.0.0 to 127.255.255.255 cannot be used and is reserved for loopback and diagnostic functions.

Private IP Addresses

Class	Private Networks	Subnet Mask	Address Range
A	10.0.0.0	255.0.0.0	10.0.0.0 - 10.255.255.255
B	172.16.0.0 - 172.31.0.0	255.240.0.0	172.16.0.0 - 172.31.255.255
C	192.168.0.0	255.255.0.0	192.168.0.0 - 192.168.255.255

Networking Interview Question

Q:What is Networking?

Inter connection between the two or more computers is called the networking. Using three types of network are Intranet, Internet and Extranet (Eg. LAN, WAN & MAN)

Q:What is Bandwidth?
Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth. Every line has a capacity of transmission of data, The maximum amount of data that can be transferred in a single line is called Bandwidth.

Q:What is VLAN?
VLAN Stand for Virtual Local Area Network. It is a logical grouping of network users and resources connected to administratively defined ports on a switch.
Uses of VLAN are as follows:-
1. It is securied connection.
2. It increases flexibility.
3. It creates separate broadcast domain.

Q:What is CIDR?
CIDR Stands for classless inter domain routing. It helps in preventing the wasting of IP address and nowadays we are facing the shortage of the IP address.So this CIDR helps to prevent the waste of IP address.Shortly IPV6 will come into exist.

Q:What is VLSM?
VLSM stands for Variable length subnet mask, when try to separate a major subnet into minor ones, then that process is called VLSM. We can subnet in various lengths.
Eg: 1.1.1.0-/24 can be separated into 1.1.1.0-/30 and 1.1.1.4-/28

Q:What is unicast?
Unicast is one type of transmission in which information is sent from one host to another host (i.e Source to Destination). In another words, Unicast transmission is between one-to-one nodes

Unicast ---> A transmission to a single interface card.

Q:What is Multicast?
Multicast is such differ from Unicast. It is another type of transmission or communication in which there may be more than host and the information sent is meant for a set of host.(i.e one source to group of destination

Multicast ---> A transmission to a group of interface cards on the network.

Q:What is Broadcast?
Broadcast is one type of transmission in which information is transfer from just one host but is received by all the host connected to the network. (i.e one source to all destination)

Broadcast ---> A transmission to all interface cards on the network.

Q:What is ACL?

ACL stands of Access Control List, It is packet filtering method, which filter the IP packets based on source and destination address. It is set of rules or condition that permit or deny the ip packets.

Cisco ACLs are divided into types.
1. Standard ACL &
2. Extended ACL.

Standard ACL - Standard IP Access Lists ranging in number from 1 to 99. Standard ACL control the traffic based on the source IP address only.

Extended ACL - Extended IP Access Lists ranging in number from 100 to 199. Extended ACL control the traffic based on the source IP address, destination IP address, source port number and destination port number.

Q:What is CEF?

Cisco Express Forwarding (CEF) is an advanced layer 3 switching technology used mainly in large core networks or the Internet to enhance the overall network performance.

CEF is mainly used to increase packet switching speed by reducing the overhead and delays introduced by other routing techniques. CEF consists of two key components: The Forwarding Information Base (FIB) and adjacencies. The FIB is similar to the routing table generated by multiple routing protocols, maintaining only the next-hop address for a particular IP-route.

The adjacency maintains layer 2 or switching information linked to a particular FIB entry, avoiding the need for an ARP request for each table lookup. There are five types of adjacencies:

1. Null adjacency.

2. Punt adjacency.

3. Glean adjacency.

4. Discard adjacency.

5. Drop adjacency.

Q:What is CDP?

CDP Stand for Cisco Discovery Protocol, It's a Layer 2 protocol and used to check the availability of neighbouring Cisco devices. It can give you all the details of the neighbours. CDP provides network device inventory, connectivity information, and IP next hop information. CDP Version-2 (CDPv2) is the most recent release of the protocol and provides more intelligent device tracking features.

Sending CDP packets every 60 seconds and

Hold time is 180 seconds.

Q:What is SNMP?

The Simple Network Management Protocol (SNMP) is an application layer protocol (Layer 1) that facilitates the exchange of management information between network devices. It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. SNMP enables network administrators to manage network performance, find and solve network problems, and plan for network growth.

Q:What is RIP and difference between Rip V1 & Rip V2?

RIP Stands for Routing information protocol. It is also called distance vector routing protocol. It is open standard for any vendor use. It uses metric as hop count (max hop count 15) AD 120. It sends periodic update for every 30 sec. It is used for small network.

Rip V1

1. It is a Class full Protocol.
2.Classful Protocol: - Supports networks with same Subnet Mask
3.RIPV1 uses Broadcast Address
4.RIPV1 Universal Broadcast (255.255.255.255)
5. RIPV1 does not VLSM.

Rip V2

1. It is a Classless Protocol.
2.Classless Protocol: - Supports subnetted networks; It carries the information of subnet mask
3.RIP V2 uses Multicast Address
4. RIPV2 uses Multicast (224.0.0.9).
5.RIPV2 supports VLSM

Q:What is EIGRP?

EIGRP stands for Enhanced Interior Gateway Routing Protocol, it is also called balanced hybrid routing protocol or advanced distance vector routing protocol. Hello packets for every 5 sec, hold time 15 sec. It support for VLSM, the multicast address is 224.0.0.10. It maintain neighbour table, topology table & routing table

Neighbour – directly connected neighbour (feasible successor)
Topology – all path reach to destination (feasible successor)
Routing – best path (successor)

DUAL: Diffusion update algorithm

Successor is available in routing table
If successor failed means it will take the feasible successor

DUAL Parameter

A.D = Advertised distance (Reported Distance)
F.D = Feasible distance

Reported Distance: The metric for a route advertised by a neighbour
Feasible distance: The distance advertised by a neighbour plus the cost to get to that neighbor

Q:What is OSPF?

Open Shortest Path First (OSPF) is a dynamic routing protocol for use in Internet Protocol (IP) networks. OSPF is designated by the Internet Engineering Task Force (IETF). Specifically, it is a link-state routing protocol and falls into the group of interior gateway protocols, operating within an autonomous system (AS). Unlimited router can be used. CPU usage will be high, to reduce the CPU Usage using area.

Q:What are the areas in OSPF?

• The backbone area, which is also referred to as Area 0. All other areas must connect to the backbone area. Hence, this area is obligatory.

• An ordinary or standard area, which is an area that connects to the backbone (Area 0) and is treated as a separate entity. All routers in a standard area have the same topological database, but their routing tables will be based on the routers position in the standard area and will thus be unique to the router.

• A stub area, which is an area that does not accept external summary routes. A router within a stub area can only see outside the autonomous system if a default route has been configuration for it.

• A totally stubby area, which is similar to a stub area. In this area, the default route must be configured as 0.0.0.0. This type of area is useful for remote sites that have few networks and limited connectivity with the rest of the network and is a Cisco proprietary solution.

• A not so stubby area (NSSA), which is a stub area that can receive external routes but will not propagate those external routes into the backbone area.

Q:What are the network types in OSPF?

1. Non broadcast - This is the default on frame relay networks has a DR/BDR election. Neighbor command needed to establish adjacency.

2. Broadcast - This is the default on Ethernet/broadcast networks. Does have DR/BDR election.

3. Point-to-point - No DR/BDR election. This one is pretty self explanatory.

4. Point-to-multipoint - Does not have a DR/BDR election. Solves some design issues with the next hop processing for NONBROADCAST. Treats as a collection of P2P links.

5. Point-to-multipoint non broadcast - Same as P2M but does not use pseudo broadcast. Must statically define neighbors.

6. Loopback - OSPF treats these as stub hosts. (/32)

Q:What are BGP and their attributes?

The Border Gateway Protocol (BGP) is an inter autonomous system routing protocol. An autonomous system is a network or group of networks under a common administration and with common routing policies. BGP is used to exchange routing information for the Internet and is the protocol used between Internet service providers (ISP). Customer networks, such as universities and corporations, usually employ an Interior Gateway Protocol (IGP) such as RIP or OSPF for the exchange of routing information within their networks. Customers connect to ISPs, and ISPs use BGP to exchange customer and ISP routes. When BGP is used between autonomous systems (AS), the protocol is referred to as External BGP (EBGP). If a service provider is using BGP to exchange routes within an AS, then the protocol is referred to as Interior BGP (IBGP).

BGP Attributes are

1. Weight 5. AS_path

2. Local preference 6. Next hop

3. Multi-exit discriminator 7. Community

4.Origin

Q:What is PPPoE?

Point to Point Protocol over Ethernet (PPPoE) is network protocols that allow data communication between two network entities or points, which supports network layer protocols including IPv4 and IPv6. PPP supports three types of user authentication protocols that provide varying levels of security.

PAP 2. CHAP 3. EAP

PAP	CHAP
1. Clear text	1. Encrypted
2. Less secure	2. High secure
3. Two way handshake method	3. Three way handshake method
Auth. Request	Challenge
Auth. Acknowledgment	Response
	Success
4. No periodic Check up	4. Periodical Check up

Extensible Authentication Protocol (EAP) is most commonly used for authentication on wireless networks

Q:What are the timers for dynamic routing protocol?

	Rip	IGRP	EIGRP	OSPF
Hello	None	None	60 sec	10 sec
Update timers	30 sec	90 sec
Dead timers	180 sec	3*hello	3*hello	4*hello

Q:What is the AD Value for Dynamic routing protocols?

	Rip	IGRP	EIGRP	OSPF	BGP
AD	120	100	90	110	20

Network And System Administrator Questions And Answers