Interview Questions.

Q1. What Is Sub Interface?

To support ISL or 802.1Q routing on a Fast Ethernet interface, the router’s interface is split into logical interfaces—one for each VLAN. These are called subinterfaces.

Q2. What Is A Mac Address Table And How A Switch Will Build A Mac Table?

To transfer frames among LAN ports efficiently, the transfer maintains an cope with table referred to as MAC address Table or CAM Table (Content Addressable Memory Table). When the transfer receives a frame, source MAC deal with is discovered and recorded within the CAM desk along side the port of arrival, VLAN and time stamp. The transfer dynamically builds the MAC address desk by the usage of the Source MAC address of the frames acquired. Than this desk is used by switch to determine wherein to ahead trafic on a LAN.

Q3. Compare Hub And Switch With Respect To Broadcast And Collision Domain?

In Hub there is one collision domain and one broadcast area.

In Switch there is more than one collision domain and one broadcast area.

Q4. How Switch Learns Mac Address?

When a frame reaches to the port of a switch, the transfer reads the MAC address of the supply device from Ethernet frame and compares it to its MAC address desk (also known as CAM (Content Addressable Memory) table). If the transfer does no longer find a corresponding entry in MAC deal with desk, the transfer will upload the address to the table with the port range at which the Ethernet body is obtained.

If the MAC cope with is already to be had inside the MAC cope with desk, the switch compares the incoming port with the port already to be had within the MAC table. If the port numbers are extraordinary, the transfer updates the MAC cope with desk with the new port range.

Q5. What Is A Broadcast Domain And A Collision Domain?

Broadcast Domain - Broadcast is a form of communique, in which the sending device send a single copy of records and that copy of information might be added to every other tool within the community segment. A Broadcast Domain consists of all of the gadgets with the intention to acquire every broadcast packet originating from any device in the network section. All ports on a hub or a transfer are by means of default in the identical broadcast domain. All ports on a router are in the one of a kind broadcast domain names and routers don't ahead broadcast.

Collision Domain - is a network scenario wherein one specific device sends a packet on a network section forcing each other tool on that same section to be aware of it. At the same time, if a extraordinary device tries to transmit concurrently, it's going to cause a collision after which both gadgets have to retransmit, one by one. This conditions is frequently in a hub surroundings, because each port on a hub is in the identical collision area. By contrast, Each port on a bridge, a transfer or router is in a seperate collision domain.

Q6. What Is Switch?

A Switch is a tool that is used to connect a couple of devices inside Local Area Network (LAN). Unlike hubs, switches examine each packet and manner it thus in preference to certainly repeating the signal to all ports. Switches perform at Layer Two (Data Link Layer) of the OSI version.

Q7. What Is Switching?

The characteristic of Switching is to Switch data packets among gadgets at the same network.

Q8. Explain Flooding?

If the vacation spot MAC address isn't determined inside the MAC cope with desk, the switch forwards the body out all of its ports except the port on which the frame turned into obtained. This is known as flooding.

Q9. What Are The Functions Of A Switch?

The Switch plays 3 predominant features:-

Address gaining knowledge of.

Packet forwarding/filtering.

Loop avoidance by Spanning Tree Protocol.

Q10. How Does Switch Performs Forwarding Function?

When a Layer2 Ethernet frame reaches a port at the Switch, it now not best reads the supply MAC address of the Ethernet body as part of getting to know feature, but also reads the vacation spot MAC deal with as a part of forwarding function. The destination MAC cope with is essential to decide the port which the vacation spot device is attached to.

As the vacation spot MAC address is observed at the MAC address desk, the transfer forwards the Ethernet body via the corresponding port of the MAC deal with.