A new series of Cisco base networking questions for 2014 - part1

Here are a number of random questions based on the Cisco certifications, but they relate to IT and networking in general as well. See how you go and check last years series for more!

(Some of these are a little tricky, just like the cert exams :-)

Action may not always bring happiness...
but there is no happiness without action.
By: Benjamin Disraeli

1. What is true about the MAC address?

A) Used to identify networks
B) Defined at the Network layer
C) Unique for every networked device in the world
D) Identical to the IP address

2. Bridges cannot provide congestive feedback information to end nodes?

A) True
B) False

3. What do asymmetric switches require?

A) memory buffers
B) extra ports
C) statically assigned ports only
D) high speed CAM

4. The Cisco Spanning Tree protocol is compatible with IEEE 802.1d?

A) True
B) False

5. What is the administrative distance of EIGRP?

A) 110
B) 1
C) 120
D) 90
E) 100

6. What IOS command would disable CDP on a routers interface?

A) no cdp enable
B) disable cdp
C) no cdp
D) no cdp run

7. Bridges forward layer 2 broadcasts, but switches don't.

A) True
B) False

8. Router>     What mode are you in when you see this prompt?

A) user exec mode
B) privileged mode
C) global configuration mode
D) interface configuration mode
E) routing protocol configuration

9. What layer of the OSI model is responsible for multiplexing upper-layer applications, establishing sessions and tearing down virtual circuits?

A) Presentation
B) Session
C) Transport
D) Network
E) Data Link

10. What is port 53 used for?

A) FTP data
B) FTP program
C) Telnet
D) DNS
E) TFTP

/center>

Answers to the above questions..

1. Correct Answer: C

MAC addresses are assigned by the manufacturer of a network interface card (NIC) and are stored in its hardware. A MAC address contains the manufacturer's identification number.
The MAC address may also be referred to as the burned-in address, hardware address, Ethernet address or physical address and is part of the Data Link layer, specifically the Media Access Control sub-layer of the Data Link layer.

2. Correct Answer: A

Flow Control and Congestive Feedback are functions of the Network layer. Bridges operate at the Data Link layer so these responsibilities fall to the end devices in a bridged environment.

3. Correct Answer: A

With ability for support of high bandwidth ports Asymmetric Switches require more Buffer memory for storing & forwarding of packets for fast processing.

4. Correct Answer: B

The original Spanning-Tree protocol was created by Digital Equipment Corporation (DEC) which is now part of Compaq. The IEEE created its own version called IEEE 802.1d which is not compatible with the original version. Cisco enhanced the original 802.1d specification with features such as Uplink Fast, Backbone Fast, and Port Fast to speed up the convergence time of a bridged network. However these new features are proprietary, and can only be configured on Cisco switches.

5. Correct Answer: D

Administrative distance is used by Cisco routers to select the best path when there are two or more different routes to the same destination from two different routing protocols. Administrative distance defines the reliability of a routing protocol. EIGRP has an administrative distance of 90.

6. Correct Answer: A

You can disable CDP on an interface which supports CDP with the no cdp enable command.

7. Correct Answer: B

Both switches and bridges forward layer 2 broadcasts.

8. Correct Answer: A

Here is a summary of Cisco IOS router command prompts:

Router> - User EXEC mode
Router# - Privileged EXEC mode
Router(config)# - Global configuration mode
Router(config-if)# - Interface level configuration mode
Router(config-router)# - Routing engine level within configuration mode
Router(config-line)# - Line level (vty, tty, async) within configuration mode

9. Correct Answer: C

The Transport layer is responsible for multiplexing upper-layer applications (ports), establishing sessions and tearing down virtual circuits.

10. Correct Answer: D

DNS uses commonly known port 53

Stay tuned for more questions ...

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Cisco Based Networking Questions part xii

Strive not to be a success, but rather to be of value. 

–Albert Einstein.

More Random Cisco Based networking Questions for you to ponder.

1, In a local broadcast all bits set to 1 received by all hosts on local and remote broadcast domains?

A) True
B) False

2. Which protocol is used to determine the IP address if the MAC address is already known?

A) ARP
B) RARP
C) IP
D) IPX
E) TCP

3. 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

4. The startup-config (Cisco) is found in the ...

A) FLASH
B) DRAM
C) NVRAM
D) ROM

5. What component of a router holds the routing tables and the software that allows the router to function?

A) Bootstrap
B) POST
C) ROM monitor
D) RAM
E) Configuration register

6. Which switching mode has the highest degree of error checking?

A) Fragment-Free
B) Fast-Forward
C) Cut-Through
D) Store-and-Forward
E) FIFO

1. Correct Answer: B
Routers don't forward broadcasts so local broadcasts will stay on the broadcast domain from which they originated.

2. Correct Answer: B
Reverse Address Resolution Protocol (RARP) is a networking protocol used by a host computer to request its IP address from an administrative host, when it knows its MAC address.

3. 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).

4. Correct Answer: C
The startup configuration is stored in NVRAM

5. Correct Answer: D
The running-config is stored in RAM and allows the router to function.

6. Correct Answer: D
Store and forward switching method is known as store and forward because the switch will store the incoming data frame in its internal buffer, then when the complete frame has been received the switch will then run a Cyclic Redundancy Check (CRC) against the frame. If the CRC passes, the switch will then look up the destination MAC Address in its MAC filter table to forward it on to its destination.

More to come - stay tuned...

Cisco Based Networking questions - part xi

Another set of 6 random IT questions to active your grey matter :-)

1. Hosts on one VLAN that want to communicate with another VLAN need to go through a router.

A) True
B) False

2. Triggered updates are used to speed the network convergence process?

A) True
B) False

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 administrative distance of RIP?

A) 110
B) 1
C) 120
D) 90
E) 100

5. What Cisco IOS command executes the configuration stored in NVRAM.

A) config t
B) config mem
C) config net
D) config start

6. Where would you place extended access lists?

A) As close to the destination as possible
B) As close to the source as possible





1. Correct Answer: A
VLANs act as if they are different networks.  So communication between VLANs require routers.

2. Correct Answer: A
A triggered update is sent immediately in response to a change in the network (e.g. A link going down). The router detecting the change immediately sends an update message to its adjacent routers, which then generate their own triggered updates. This process continues until the network converges. Triggered updates occurs independently from the regular routing updates and are intended to speed the convergence process.

3. Correct Answer: E
Trick question. IP provides NO form of error correction/acknowledgements.

4. Correct Answer: C
Here in the question the A is administrative distance 110 for OSPF, B is 1 for Static Route, D is 90 for Internal EIGRP, E is 100 for IGRP so the last C is 120 for RIP.

5. Correct Answer: B
config mem executes configuration commands stored in NVRAM by copying startup-config to the running-config

6. Correct Answer: B
Extended access lists are much more granular than standard ACLs, you can block specific ports or protocols. To avoid unnecessary traffic on your network place them as close to the source as possible.

Subnets and subnet masks

One of the most complex tasks TCP/IP has to perform is to determine whether or not a given IP address exists on the same subnet. The task isn’t really that complicated once you understand how TCP/IP uses its IP address and subnet mask, here's a very basic rundown.

An IP address looks something like this: 192.168.10.52. IP addresses always contain four numbers from 0–255, separated by periods. A portion of the IP address is called the network ID and acts as a unique identifier for a particular subnet.

The rest of the IP address is called the host ID and identifies a particular computer or network device on that subnet uniquely. How can you tell which part of the IP address is which? By using the subnet mask. A subnet mask looks a lot like an IP address, with four groups of numbers: 255.255.255.0. Remember, computers are binary machines that can understand only in zeros and ones. For the subnet mask to make sense, you have to translate it and the IP address into binary.
 

TIP: You can switch the Windows Calculator into Scientific view, which enables you to convert numbers from decimal to binary.


Convert all the four groups (octets) of numbers into binary code. For example, an IP address of 192.168.10.41 and a subnet mask of 255.255.255.0 look like this in binary:


Address or Mask 1st octet 2nd octet 3rd octet 4th octet

192.168.10.41 11000000 10101000 00001010 00101001

255.255.255.0 11111111 11111111 11111111 00000000



Everyplace you see a “1” in the subnet mask corresponds to the portion of the IP address that is the network ID. Everyplace you see a “0” in the subnet mask corresponds

to the portion of the IP address that is the host ID. Here, the network ID is 192.168.10, and the host ID is 41.TCP/IP treats everything with an IP address that starts with 192.168.10 as if it were on the same subnet. Any IP address that starts with something other than 192.168.10 is treated as if it existed on another subnet. 

 
Basic TCP/IP Services

A number of the protocols in the TCP/IP suite are considered core protocols, which means they are usually present on any network that uses TCP/IP. The core protocols provide basic services that no network can do without. These services include

_ Data transmission. Is handled by more than one protocol: the User Datagram Protocol (UDP) and the Transport Control Protocol (TCP). Computers use UDP when they need to send a small packet of data and don’t care if the remote computer actually receives the data. Computers use TCP when loads of data needs to be transmitted because TCP allows the remote computer to reply, confirming its receipt of the data.

_ Name resolution. Provided by the Domain Name System, or DNS, protocol. DNS enables people to use easy-to-remember names like www.microsoft.com and allows computers to translate those names to numeric IP addresses.

_ Windows Internet Name System (WINS). Prior versions of Windows also use WINS to convert computer names into IP addresses. Windows Server 2003 is compatible with WINS.


   “ We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths.”

― Walt Disney
 
References:
Sybex(2003): Mastering Windows Server 2003

Cisco exam questions part viii

Another set of mixed up networking questions to get the grey matter ticking - enjoy.





1. By default is CDP enabled or disabled on compatible devices?

A) Enabled
B) Disabled

2. What is the default setting on a router for the invalid timer if you are using IGRP?

A) 90 seconds
B) 30 seconds
C) 280 seconds
D) 270 seconds
E) 180 seconds

3. What are the default metrics of IGRP?

A) Delay, Bandwidth
B) Load, Reliability
C) Reliability, Bandwidth
D) Delay, Reliability

4. What WLAN standard operates in the 5GHz band with a data rate of up to 54Mbps?

A) 802.11a
B) 802.11b
C) 802.11g
D) 802.11h
E) 802.11n

5. Where is the best position to place an Extended ACL?

A) As close to the destination as possible
B) As close to the source as possible

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1. Correct Answer: A

Explanation
CDP is enabled on Cisco routers by default. To disable CDP use the no cdp run command.

2. Correct Answer: D

Explanation
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).

3. Correct Answer: A

Explanation
IGRP and EIGRP use multiple metric parameters to calculate their composite metric.  These are bandwidth, delay, load, and reliability. By default, IGRP chooses a route based on bandwidth and delay.

4. Correct Answer: A

Explanation
802.11a operates in the 5GHz band with a data rate of up to 54Mbps and is immune to interference from other devices operating in the 2.4GHz spectrum.

5, Correct Answer: B

Explanation
The general rule is to place standard ACLs as close to the destination as possible and to position extended ACLs as close as possible to the source of the traffic that will be denied. This is because extended ACLs can take in to account source and destination addresses as well as port numbers.

Random networking questions for you

Here are a few more ideas 

to get the grey matter ticking,

 all Cisco based questions, enjoy.

1. Which switching mode has the highest degree of error checking?

A) Fragment-Free
B) Fast-Forward
C) Cut-Through
D) Store-and-Forward
E) FIFO

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. Router(config-router)#

What mode are you in when you see this prompt?

A) user exec mode
B) privileged mode
C) global configuration mode
D) interface configuration mode
E) routing protocol configuration

4. 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

5, What IP address will test the internal loopback of a node?

A) 127.0.0.1
B) 255.255.255.255
C) 0.0.0.0
D) 126.0.0.1
E) 127.0.0.0

6. The maximum default hop count for Routing Information Protocol (RIP) is?

A) 1
B) 10
C) 15
D) 16
E) 30





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1. Correct Answer: D

Store and forward switching method is known as store and forward because the switch will store the incoming data frame in its internal buffer, then when the complete frame has been received the switch will then run a Cyclic Redundancy Check (CRC) against the frame. If the CRC passes, the switch will then look up the destination MAC Address in its MAC filter table to forward it on to its destination.

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: E

Here is a summary of Cisco IOS router command prompts:

Router> - User EXEC mode
Router# - Privileged EXEC mode
Router(config)# - Global configuration mode
Router(config-if)# - Interface level configuration mode
Router(config-router)# - Routing engine level within configuration mode
Router(config-line)# - Line level (vty, tty, async) within configuration mode

4. Correct Answer: D

4 bit mask = 16 subnets

5. Correct Answer: A

127.0.0.1 is the loopback address in IP, it is a test mechanism for network adapters. Messages sent to 127.0.0.1 do not get delivered to the network. The NIC intercepts all loopback messages and returns them to the sending application.

6. Correct Answer: C

The maximum allowable hop count for RIP is 15 by default. 16 is unreachable.

How did you go? leave a comment if you found these helpful, thanks.

“Don't cry because it's over, smile because it happened.”

- Dr. Seuss

The Roots Of Radio Hobbyists

Radio hobbyists can play with their equipment all day without giving a thought to the origins of their hobby. Early radio hobbyists were part of something that was, at the time, new and fairly crazy.

After radio technology was stabilized, there was a steady growth of radio signaling in the fields of navigation of ships and for rescue operations. On the other hand, the amateur radio operators also started to dominate the air. The first documented and famous amateur wireless enthusiast was a then young man named Irving Vermilya born in 1890 when wireless transmission was being born. The young man since age 12 heard Marconi and built his own wireless transmission equipment and was often "heard" telegraphing with ships during that time. In 1911 he became a member of the Radio Club that had been formed. He got himself certified in 1912 when law mandated all wireless operators to be certified. In his own words,

This was pre-audio era, and communication was purely in Morse code. Irving then organized his own amateur group who had regular meetings monthly and would communicate daily wishing "GM" (good morning) and "GN" (good night), some of the first amateur jargon to be used. He also proceeds to describe in his series of articles published in QST magazine in 1917 as to how they managed to lay the telegraph lines and such and how they "drew juice" for the wireless operation from the electric lines instead of relying on batteries.

Meanwhile, apart from the "professionals" and "amateurs", with audio wireless signal transmission there was a new revolution setting in. A Dutch engineer in Hague was the first to make regular wireless transmission via radio. This could be considered the first regular radio broadcast. After this there was slow development until the commercial radio stations came into being.

The requirement to be certified killed the enthusiasm in many amateurs, and the number of amateurs dwindled. But then after WWI, there was a boom. The first radio clubs were formed in 1909 and this was the beginning of the radio hobbies which included radio as a part of the hobby activity.

During the WWI the amateur radio operators were asked to stop their activity and dismantle the equipment. Radio operators in uniform helped in military communications. They got back on the air again by November 1919 again. A similar lull in amateur radio happened during Second World War and got back on air by 1946. After lots of battles over the frequency range that the amateurs can tune into, the amateur radio is here to stay!

At present there are more than 170,000 ham operators which is possibly not the complete picture. It is still increasing. So, with Irving Vermilya was born the amateur radio operation, since he was the first radio hobbyist. After lots of developments, including the discovery of the transistor which greatly decreased the size of the radio equipment, the old ways still remains which included "waiting for someone to signal".

The rules to get oneself certified and licensed included a Morse code proficiency until the World Radiocommunication Conference in Geneva in 2003 that eliminated the need for Morse code proficiency from the licensure tests. Taking effect from February 23, 2007 the Morse code has been eliminated from the tests for amateur radio license tests.