Wednesday, November 26, 2014

Networking Questions and Answers



Here's another set of Cisco based networking questions to mull over - enjoy!




1. How would you copy the IOS to a TFTP server?

A) Router(config)#copy ram tftp
B) Router(config)#copy tftp flash
C) Router#copy flash tftp
D) Router#copy tftp flash
E) None of the above 


2. What determines network addresses when data link addresses are known?

A) Ping
B) ICMP
C) ARP
D) RARP


3. What process is used to check whether packets have been received when using IP?

A) Acknowledgments
B) CRC
C) Windowing
D) Flow control
E) None


4. What is the maximum number of subnets given the following?

192.168.10.0
255.255.255.192
(Assume ip subnet-zero is enabled)

A) 4
B) 8
C) 16
D) 32
E) 64


5. Ip subnet-zero is enabled on all your routers.
How many bits must you borrow to create 16 subnets?


A) 1
B) 2
C) 3
D) 4
E) 5


6. What is the maximum size of an Ethernet packet when the frames have ISL tagging?(Include the size of headers and CRC)

A) 64 bytes
B) 1500 bytes
C) 1518 bytes
D) 1522 bytes
E) 1548 bytes


7. Which of the following are Routed protocols?

A) IP, IPX, ICMP
B) IP, IPX, Appletalk
C) RIP, IGRP, EIGRP
D) Both A and B are correct


8. What is the encapsulation type of Transport Layer?

A) Segments
B) Packets
C) Frames
D) Bits


9. What does Router(config)# no access-list 1 command achieve?

A) Removes Access List 1
B) Disables ACL on interface 1
C) Nothing, this is not a Cisco command


10. What is the numerical value of the Bridge Priority held by Catalyst switches?

A) 32500
B) 32768
C) 100
D) 1024
E) 32700







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1. Correct Answer C

It is a good practice to backup your existing system image to the TFTP server using the copy flash tftp command.


2. Correct Answer D

Reverse Address Resolution Protocol (RARP) is used by a host computer to request its IPv4 address from an administrative host, it provides the administratiev host with its hardware address (MAC address).

http://en.wikipedia.org/wiki/Reverse_Address_Resolution_Protocol


3. Correct Answer E

Trick question. IP provides no form of error correction/acknowledgements.


4. Correct Answer A

192.168.10.0 is a class C address.  The subnet mask 255.255.255.192 implies 2 bits are borrowed.
22 = 4 subnets


5. Correct Answer D

24 = 16


6. Correct Answer E

Cisco's proprietary VLAN tagging (ISL) has a maximum frame size of 1548 bytes.
IEEE 802.1q VLAN tagging has a maximum frame size of 1522 bytes.


7. Correct Answer D

Routed Protocols are layer 3 Network Layer protocols. They include Internet Protocol (IP), Internetwork Packet Exchange (IPX) and Apple's AppleTalk. Routed or routable protocols allow for internetwork communication by assigning network and host identities to packets, without routed protocols network communication would be restricted to the local segment.

Internet Control Message Protocol (ICMP) is a TCP/IP protocol that works at the network layer and is used to report errors and deliver messages. ICMP is also considered a routed protocol.


8. Correct Answer A 

The Transport layer protocol data unit (PDU) is the 'Segment'


9. Correct Answer A

If you wish to remove an access-list, you use the no access-list (list #) command.


10. Correct Answer B 

The Bridge Priority is the numerical value held by switches. All Catalyst switches have a default priority of 32768. To determine the root bridge you combine the priority of each bridge with its MAC. If two switches have the same priority value the lowest MAC address becomes the root bridge.

 How did you go - Interesting huh - More coming stay tuned... Have a great day!!!


Monday, November 24, 2014

Millimetre-wave WiFi devices.


Samsung preps 4.6Gbps millimetre-wave WiFi devices.




Known as WiGig, the 802.11ad standard transmits in the unlicensed 60GHz frequency band for high performance up to 4.6 gigabits per second in Samsung's designs, while remaining backwards compatible with the previous 2.4GHz and 5GHz Wi-Fi standards.

Compared to today's 802.11ac which provides a maximum throughput of 867 megabits per second per stream under ideal conditions, 802.11ad devices can reach speeds as fast as 7 gigabit/s.

The high frequency used for WiGig results in path loss and poor wall and floor penetration of the signal, leading to shorter reach than existing Wi-Fi.

Samsung said it has solved these issues with millimetre-wave circuit design, improved transmission technology and a wide-coverage beam-shaping aerials. This, the company said, would make WiGig commercially viable in retail devices.



Read more: http://www.itnews.com.au/News/396733,wigig-coming-to-samsung-devices.aspx#ixzz3G6aWIlAc




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Friday, November 21, 2014

Networking Questions And Answers

Another random batch of Cisco based networking questions to ponder, enjoy.



1. What is the default VTP mode of operation for the Cisco Catalyst switch?

A) Client
B) Server
C) Transparent


2. Router(config)#access-list 150 deny tcp any host 172.32.14.2 eq 25

What type of ACL is this and what is it performing?

A) Standard ACL, deny all SMTP traffic to host 172.32.14.2
B) Standard ACL, deny all Telnet traffic to host 172.32.14.2
C) Extended ACL, deny all SMTP traffic to host 172.32.14.2
D) Extended ACL, deny all Telnet traffic to host 172.32.14.2
E) Named ACL, deny all SMTP traffic to host 172.32.14.2


3. Rapid Spanning Tree Protocol (RSTP) can only run on Cisco switches?

A) True
B) False


4. When STP is converging no data can move through the switched network.

A) True
B) False


5. What class is the following IP address?
192.150.0.5

A) Class A
B) Class B
C) Class C
D) Class D


6. Which layer of the OSI reference model allows for internetwork connectivity?

A) Presentation layer
B) Datalink layer
C) Layer 2
D) Network layer
E) Application layer


7. What is the invalid timer set to by default when you have a router running the Interior Gateway Routing Protocol?

A) 3 times the update period
B) 270 seconds
C) 3 times the update period + 10 seconds
D) Answer A and B
E) 7 times the update period


8. How many access control lists can you apply to an interface?

A) Unlimited
B) One ACL per port per direction
C) 10
D) You do not apply ACL to interfaces


9. What does the trace response N mean?

A) Network unreachable
B) Not forwarded due to ACL restriction
C) Protocol unreachable
D) Port could not be reached


10. What is the maximum number of hosts you can assign to a class C network if it is not subnetted?

A) 1024
B) 254
C) 32
D) 512
E) 65025





 
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1, Correct Answer B

The default mode for all Catalyst switches is Server.
A VTP domain requires at least one VTP server.


2, Correct Answer C

Router(config)#access-list 150 deny tcp any host 172.32.14.2 eq 25

Port 25 is SMTP. This extended ACL denies traffic from any source to host 172.32.14.2.


3. Correct Answer B

RSTP (802.1w) is a new Spanning Tree Protocol that can run on any brand of switch.  It can even inter-operate with legacy STP protocols!

4. Correct Answer A

http://en.wikipedia.org/wiki/Spanning_tree_protocol

5. Correct Answer C

The first octet of a class C IP address ranges from 192 - 223


6. Correct Answer D

The Network layer of the OSI model is the layer that defines how internetworks (interconnected networks) function. The Network layer is concerned with getting data from one computer to another even across remote networks.


7. Correct Answer D 

IGRP sends its routing table to its neighbors every 90 seconds. IGRP uses an invalid timer to mark a route as invalid after 270 seconds (three times the update timer). IGRP uses a flush timer to remove a route from the routing table (default flush timer is 630 seconds, seven times the update period).


8. Correct Answer B 

Cisco routers only allow you to place one access control list (ACL) per direction.

9. Correct Answer A

Cisco Trace Command Response Codes

Response Meaning
 * Timed out
 !H router received packet but did not forward it
 N network unreachable
 P protocol unreachable
 U port unreachable



10. Correct Answer B

For class C the number of bits for host address portion is 8. So 2^8 -2 = 256-2 = 254 hosts.




How did you go?  Stay tuned for more - have a great day!