Random Cisco based networking questions - CCNA - Part 3

Welcome to part 3 of the random networking questions (Cisco based) series.

Ready to get the brain tickin? Lets go!

1. What Cisco IOS enhanced editing command end the configuration mode and returns to EXEC?

A) Ctrl+Z
B) Ctrl+W
C) Ctrl+F
D) Esc+F
E) Tab

2, Which devices operate at the Data Link layer?

A) Switch
B) Bridge
C) Repeater
D) Router
E) Both A and B

3. Triggered updates are used to speed the convergence process?

A) True
B) False

4. Which switching mode is the most likely to forward frames containing errors?

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

5. What is the function of asymmetric switching?

A) To prioritise bandwidth to nodes that need it
B) To prevent bottlenecks on the port a server is connected to
C) To allow RAS clients to connect to the network

6. PPP can be used over what types of serial connections?

A) Synchronous
B) Asynchronous
C) Both
D) Neither










1. Answer A

Keyboard Shortcut Actions (I've published this before but thought it worthy to remind :-)

Up Arrow Displays your previous commands.  (command history)
TAB Key Completes a partially typed CLI commands.
CTRL+Z Takes you back to Privileged EXEC Mode.

CTRL+A Places the cursor at the beginning of a line.
CTRL+E Places the cursor at the end of a line.
CTRL+R Redisplays the current command line.
CTRL+W Erases a word (behind the cursor).
CTRL+U Erases an entire line.

2. Answer E

Bridges and switches filter network traffic based on the MAC address (hardware address) and are Data Link layer devices.

A Repeater does not apply any filtering and is therefore a Physical Layer device.

Routers forward packets based on logical network addresses are are Network Layer devices.

3. 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.

4. Answer D

Cut-Through switching is also referred to as Fast Forward.

When in cut-through mode the switch waits for the destination MAC Address to be received. Once the MAC Address is known the switch refers to its MAC filter table to determine which port the frame should be forwarded out. The switch forwards the frame even before the entire frame has arrived.

Frames with and without errors are forwarded in cut-through switching, leaving the error detection of the frame to the intended recipient.

5. Answer B

An asymmetric switch provides switched connections between ports of different bandwidths.
Asymmetric switching is optimized for client-server traffic where multiple clients simultaneously communicate with a server, requiring more bandwidth dedicated to the server port to prevent a bottleneck at that port.

6. Answer C

Point-to-Point Protocol (PPP) can be used over ISDN (synchronous) and dial-up (asynchronous) connections.

All over the place that time - stay tuned for the next batch - coming soon:-)

  “Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for.”
 Socrates 

Random Cisco based networking questions - CCNA - Part 2

Part 2 in the series of random networking questions for 2015, to keep you current or stimulate thought..

 1. Where would you place more specific tests in your access list?

A) At the top
B) At the bottom
C) Placement doesn't matter


2. Routers are what by default?

A) DTE devices
B) DCE devices

3. Which WAN protocol is capable of carrying video, Circuit Switched Data And Telephone Services using normal phone network?

A) Frame Relay
B) ISDN
C) PPP
D) ISL

4. What protocol range would you use for IP in ACLs?

A) 1-99
B) 800-899
C) 200-299
D) 1000-1099

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. When each network segment uses a different subnet mask this is refered to as...

A) Classful routing
B) Classless routing












1. Answer A

Always organise your access lists so the more specific tests are at the top.

2. Answer A

A router is configured as a DTE by default. If a clock rate speed is not specified, the router is configured as a DTE. If a clock rate speed is specified, the router is configured as a DCE.

DTE = Data Terminal Equipment
DCE = Data Communications Equipment

 3. Answer B

ISDN (Integrated Services Digital Network) is a set of standards for simultaneous digital communications (voice, video, data) over the traditional circuits of the public switched telephone network.

4. Answer A

Standard Cisco IOS Help output
Router#configure terminal
Router(config)#access-list ?
 <1-99>  IP standard access list
 <100-199> IP extended access list
 <1100-1199> Extended 48-bit MAC address access list
 <1300-1999> IP standard access list (expanded range)
 <200-299> Protocol type-code access list
 <2000-2699> IP extended access list (expanded range)
 <700-799> 48-bit MAC address access list
 rate-limit Simple rate-limit specific access list

5.  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. Answer B

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

More coming, please leave comments if you find any errors or want to debate an answer :-)

"Whatever you are, be a good one."

Abraham Lincoln

Random Cisco based networking questions - CCNA - Part 1

The first half a dozen of random networking questions to get you thinking in 2015 :-)

Enjoy,,

1. Where would you place extended access lists?

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

2. Bridges can only have one spanning tree instance, while switches can have many.

A) True
B) False

3. What would happen if you put the following ACL on an interface?

access-list 1 deny 172.168.0.1
access-list 1 deny 192.5.2.1

A) All traffic from 172.168.0.1 and 192.5.2.1 would be denied
B) All traffic would be denied
C) Nothing
D) These are not Cisco IOS ACL commands

4. Which layer of the OSI model is concerned with Media Access Control addresses?

A) Layer 1
B) Datalink layer
C) Application Layer
D) Session Layer
E) Transport Layer

5. What do the IOS commands below achieve?

Router(config)#access-list 5 permit 172.5.15.2
Router(config)#line vty 0 4
Router(config-line)#access-class 5 in

A) Create an extended ACL to only permit host 172.5.15.2 to connect to VTY
B) Create a standard ACL to only permit host 172.5.15.2 to connect to VTY
C) Create an extended ACL to only permit hosts on the network 172.5.15.2 to connect to VTY
D) Create a standard ACL to only permit hosts on the network 172.5.15.2 to connect to VTY
6. What is the Spanning Tree forward delay?

A) The time that is spent in the Listening and Learning states
B) 50 seconds
C) Time taken for a switch to go from Listening to Forwarding
D) Time taken for a switch to go from Blocking to Forwarding









1. 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.

2. Answer A (true)

Bridges are software based and can only have one spanning-tree instance per bridge, while switches are hardware based and can have many.

3. Answer B

People forget the not shown the automatic deny any any on the tail end of any access list :-)

4. Answer B

Media Access Control is a sublayer of the Data Link Layer specified within the OSI model. It provides addressing and channel access control.  The hardware that implements the MAC is referred to as a Media Access Controller.

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

5. Answer B

Router(config)#access-list 5 permit 172.5.15.2
Router(config)#line vty 0 4
Router(config-line)#access-class 5 in

This standard access list permits only the host 172.5.15.2 to connect to your VTY telnet line.

6. Answer A 

Forward delay — The time that is spent in the listening and learning state, 15 sec by default, but you can tune the time to be between 4 and 30 sec.

How did you do?? stay tuned more coming or check out the previous posts :-)

"If you want success, then don't rely on other people to do what YOU can do!" 

Sasha Azevedo