Extending Switched Networks with VLANs

Question 1

What are VLANs ?

Answer 1

VLANs are broadcast domain in a Layer 2 network, acting as virtual bridges

Question 2

How does standalone switch treat a broadcast frame?

Answer 2

The switch will forward the packet to all ports except where it was received.

Question 3

What are trunk links?

Answer 3

Trunks links allow switches carry multiple VLANs across a single link

Question 4

Which network attack is executed by using multiple hosts to flood the network?

Answer 4

Distributed Denial of Service (DDoS)attack

Question 5

In which IPv4 to IPv6 migration deployment model is encapsulation of IPv6 traffic into IPv4 packet done?

Answer 5

IPv6 over IPv4 tunnels

Question 6

which IOS command is used to clear the matches for filter rules in an access list?

Answer 6

Clear ip access-list counters command

Question 7

Describe 802.1Q tagging.

Answer 7

It does this by using an internal process that modifies the existing Ethernet frame with the VLAN identification.

Question 8

What is per-VLAN Spanning Tree (PVST+)?

Answer 8

PVST+ runs one instance of the Spanning Tree Protocol per VLAN, allowing you assign root bridge for each VLAN

Question 9

What is Inter-Switch Link (ISL)?

Answer 9

ISL is a Cisco-proprietary protocol used to interconnect switches that have multiple VLANs

Question 10

What type of tagging method does ISL use?

Answer 10

ISL tags frames as an external tagging mechanism, ISL encapsulates each frame and does not modify the original packets

Question 11

How many extra bytes does ISL add to an existing Ethernet frame?

Answer 11

ISL adds 26-byte ISL header and a 4-bytes CRC to each frame, extending each ethernet frame

Question 12

What is VTP ?

Answer 12

VTP is layer 2 messaging protocol maintains VLAN configuration , managing VLAN additions, deletions and name changes.

Question 13

What is VTP server mode?

Answer 13

VTP server mode can add, delete, and modify VLANs and other configuration parameters for the entire VTP domain. It is the default mode for all Catalyst switches.

Question 14

What is VTP client mode?

Answer 14

VTP client mode, a switch cannot create, delete, or modify VLANs. Also, a VTP client does not save VLAN information and configuration in NVRAM.

Question 15

What is VTP transparent mode?

Answer 15

transparent mode, a switch can add, modify, and delete VLANs locally. A VTP transparent does not advertise or synchronize its VLAN configuration

Question 16

How often are VTP advertisements flooded throughout the management domain?

Answer 16

VTP advertisements are flooded throughout the management domain every 5 minutes or whenever a change occurs

Question 17

What is VTP pruning?

Answer 17

Even if a switch does not have any ports in a specific VLAN, traffic for that VLAN is carried across the trunk link. VTP pruning uses VLAN advertisements to determine when a trunk connection is needlessly flooding traffic to a switch that has no ports in the particular VLAN.

Question 18

What is included in VTP advertisements?

Answer 18

VTP revision number,VLAN names and numbers, Information about switches that have ports assigned to each VLAN

Question 19

What is one of the most important components of the VTP advertisement?

Answer 19

revision number is the most important components of the VTP advertisement,it increments the configuration number by 1 using the largest configuration number as the most current information