netwrok engg int. question

8/7/2019 netwrok engg int. question

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Interview Question for network Engg.

What is ping? Why you use ping?

PING Stands for Packet Inter Net Gopher. PING is used for connectivity checking of

any network or any host or device of any or other networks.

Routers are always preferrable for routing

services. Routers work at which OSI layers?

Router works at network layer for providing routing services between or among

several networks.

A gateway works in which layer?

Transport layer of OSI model.

How can you check the connectivity of any network?

By using ping command.

What is a gateway?

A gateway acts a door for the packet to reach the ‘outside’ of the internal network.

What are the differences among router, switch,

bridge and hub?

Router, switch, bridge and hub are network devices. Yet there are some differences

among them. The main differences are:

• Router: A layer 3 device, can work on physical, data and network layer.

• Switch: A layer 2 device, can work on data link layer

• Bridge: A layer 2 device, can work on data link layer.

• Hub: A layer 1device, just a multi-port repeater and works on physical layer

What is the range of class A address?

0-127 is the range of class A address.



Tell an IP which has class C range. Also tell why that

IP is an class C address.

• IP of Class C: 193.1.1.1

• Why this is a class C address: Class C addresses have the range of 192 - 223

Name a device which can operate at physical layer of

OSI model.

Hub.

Note: Remember, hub is the device that can work only into the physical layer of OSI

model. But switch, router can also be used instead of a hub. So, all the answers hub,

switch or router are all correct.

What is the major differences between a router and a

switch?

A router can divide the broadcast domain and collision domain. But a switch can only

divide the collision domain. Router can communicate among different networks

where as the switch can not communicate different networks.

Hub operates at which layers of OSI model? Is it wise

to use a hub for huge networks? Why or why not?

• Hub operates at only physical layer of OSI model.

• No, it's not so wise to use hub for a huge network.

• Hubs can't divide the broadcast domain or the collision domain. So, if we use

hubs then there creates huge broadcast domain. When there are huge

broadcast, the network gets problem time to time. So, it's not wise to use hubs

to support a huge network.

How many layers are in OSI model? Name them

There are seven layers of OSI model. The layers are:

1. Application layer

2. Presentation layer

3. Session layer

4. Transport layer

5. Network layer

6. Data link layer

7. Physical layer



• POP3 port no: 110

What is the functionality of network layer? Name the

data unint of network layer.

• Functionality of network layer: Path determination and logical addressing

• Data unit of network layer: Packet

Which three layers of OSI model is treated as "Media

Layers"?

Physical layer, data link layer and network layer are treated as "Media Layers".

What is deadlock?Deadlock is a situation when two or more processes are waiting indefinitely for an

event that can be caused by only one of the waiting processes. The implementation of

a semaphore with a waiting queue may result in this situation.

Mention the advantages and disadvantages of a

router.

Advantages:

• Router can limit the collision domain and broadcast domain

• Router can function both on LAN & WAN.

• Different media & architectures can be connected among themselves through

router.

• Router can determine best path/route for data to reach

• the destination.

• Router can filter the broadcasts.

• For communicating different networks, routers must be used.

Disadvantage:

• Router is more expensive than any other networking devices like Hub, Bridge

& Switch.

• Router only work with routable protocols.

• Routing updates consume some bandwidth.

• Increase latency due to greater degree of packet

• filtering.

• Routers function as software based and so it's slower compared to switch.

Mention the private IP address rannge of class B and

C.



• For Class B: 172.16.0.0 – 172.31.255.255

• For Class C: 192.168.0.0 – 192.168.255.255

What is the IP range of class C IP address?

240.0.0.0 255.255.255.255

What is the default subnet mask of class C IP

address?

255.255.255.0

Why do you need subnet mask?

Subnet mask is required to divide a large network into several small networks.

Tell the full name: DNS, FTP

• DNS: Domain Name System

• FTP: File Transfer Protocol

What is the functionality or ARP?

ARP refers to Address Resolution Protocol. ARP is a computer networking protocolfor determining a network host's link layer or hardware address when only its Internet

Layer (IP) or Network Layer address is known.

Which one is reliable: TCP or UDP?

TCP is reliable and UDP is an unreliable service.

How DHCP works?

DHCP works by four-steps: (1) IP request, (2) IP offer (3) IP selection and (d)Acknowledgement.

What is POP3? Why you require POP3?

POP stands for Post Office Protocol. This is used to describe how e-mail clients

interact with mail servers. The POP3 Server is a type of mail server used for incoming

mail. POP is only used to receive messages.

What is the difference between Layer 2 Switch and

Layer 3 Switch?



Layer 2 switch is based on MAC addresses which operates on Data Link Layer of OSI

mode. And Layer 3 switching is based on network topology table populated and

works on Network layer.

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