Wednesday, February 26, 2014

A new series of Cisco base networking questions for 2014 - part2

A set of questions for those interested in IT / networking / certification or just generally curious  - Enjoy.
(This time with some IPv4 questions thrown into the mix :-)

The secret of life is not to do what you
like but to like what you do.

By: Anonymous

1. What will be the IP address of the second subnet given the following? (Assume ip subnet-zero is enabled)


2. What is the maximum number of subnets and hosts per subnet achievable from the network

A) 2048 subnets and 30 hosts
B) 256-224=32 ip per subnet - 30 hosts
C) 256/32=8 subnets per 4th octet
D) 256 x 8 = 2048 total subnets for B class address

3. What are the 3 ways of assigning a switched port to VLANs?

A) Switch-centric, Port-centric, Dynamic VLANs
B) Port-centric, Static VLANs, Dynamic VLANs
C) Interface-based, Static VLANs, Dynamic VLANs

4. What is the default time BPDUs are sent and received by switches?

A) 2 seconds
B) 10 seconds
C) 30 seconds
D) 60 seconds

5. 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

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1. Correct Answer: D 

The subnet block size is 256 - 224 = 32
The first subnet will be subnet zero
The second subnet will be

2. Correct Answer: A

2048 subnets and 30 hosts

3. Correct Answer: B

Three ways of assigning a switched port to VLANs:

Port-Centric - All nodes connected to ports in the same VLAN are assigned to the same VLAN ID.
Static VLANs - Statically assign ports to a VLAN.
Dynamic VLANs - Ports that can automatically determine their VLAN assignments based on MAC addresses.

4. Correct Answer: A 

The Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree also allows a network design to include spare (redundant) links to provide automatic backup paths if an active link fails, without the danger of bridge loops, or the need for manual enabling/disabling of these backup links.

The bridges have to determine the root bridge and compute the port roles (root, designated, or blocked) with only the information that they have. To ensure that each bridge has enough information, the bridges use special data frames called Bridge Protocol Data Units (BPDUs) to exchange information about bridge IDs and root path costs.

A bridge sends a BPDU frame using the unique MAC address of the port itself as a source address, and a destination address of the STP multicast address 01:80:C2:00:00:00.

There are two types of BPDUs in the original STP specification (The Rapid Spanning Tree (RSTP) extension uses a specific RSTP BPDU.[4]):

Configuration BPDU (CBPDU), used for Spanning Tree computation
Topology Change Notification (TCN) BPDU, used to announce changes in the network topology
BPDUs are exchanged regularly (every 2 seconds by default) and enable switches to keep track of network changes and to start and stop forwarding at ports as required.

5. Correct Answer: A

"No" is generally used in front of Cisco config lines to remove them from configuration, in this case No Removes Access List 1

More questions Coming - see you soon...

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