Network Intro, Osi Reference Model

Front 1

What is an Ethernet Cable code

Back 1

RJ45

Front 2

How many types of messages are there

Back 2

3 - Unicast, broadcast, multicast

Front 3

What is a unicast message

Back 3

A message from one host to another

Front 4

What is a multicast message

Back 4

Message from one host to multiple devices

Front 5

What is a broadcast message

Back 5

Message from one host to all devices

Front 6

What is a Collison domain

Back 6

Network scenario where one device sends a frame out on a physical network segment forcing every other device on the same segment to pay attention to it

Front 7

What is a broadcast domain

Back 7

It's a network scenario in which all the devices in the network segment are allowed to hear a broadcast sent out on that network segment

Front 8

What are hubs

Back 8

1. L1 device

2. Is a multiport receiver i.e. receives a digitalsignal, reamplifies or regenerates the signal, then forwards the signal out theother ports without looking at the data, except to the one from which it was received

3. LAN connection

4. Provides single collision domain

Front 9

Which layer does a hub work on?

Back 9

L1

Front 10

How many collision domains are there in a hub network

Back 10

1

Front 11

Hubs are synchronous with which type of network

Back 11

LAN

Front 12

What are Switches

Back 12

1. They forward & filter or switch frames sent by a host by checking the MAC address

2. Break up Collison domains

3. LAN

4. L2 switching is considered hardware based bridging because it uses a specialized hardware called an ‘application specific integrated circuit’ ASIC

Front 13

What message type is associated with switches

Back 13

Frames

Front 14

How does a switch operate

Back 14

By checking MAC addresses

Front 15

How many collision domains are there in a switched network

Back 15

As many collision domains as there are ports in the switch

Front 16

Which layer does a switch operate on

Back 16

Layer 2

Front 17

Which network does a switch belong to

Back 17

LAN

Front 18

What is a Router

Back 18

1. L3 switch

2. It can interconnect networks and fleet networks based on L3

3. WAN and serial interface for WAN connections i.e. v.35

4. Breaks up broadcast donations

5. Packet switching - switches packets between networks based on logical addressing and access lists

6. Path selection -chooses the best path to reach a network using routing tables

7. Packet filtering - can drop or forward a packet based on their source destination

Front 19

What layer does a router work on

Back 19

L3

Front 20

What is the WAN interface for a Cisco router

Back 20

V35

Front 21

How many broadcast domains are there in a routed network

Back 21

There can be as many domains as the number of connected hosts

Front 22

What network is a router associated with

Back 22

WAN

Front 23

What is packet switching

Back 23

Switching of packets between networks based on logical addressing and access lists

Front 24

How does a router perform path selection

Back 24

It chooses the best path to reach a network by using routing tables

Front 25

How does a router preform packet filtering

Back 25

It can drop or forward packets based on their source destination

Front 26

What are the causes of congestion in a LAN

Back 26

1. Too many hosts in the collision on broadcast domain

2. Broadcast storms

3. Too much multicast traffic

4. Low bandwidth

5. Bunch of ARP broadcasts

Front 27

What is ARP

Back 27

Used for mapping network address to physical address

Front 28

What is a VLAN

Back 28

It is a logical breakup of a broadcast in a L2 switched network

Front 29

How does a switch work?

Back 29

1. It reads each frame that passes through thenetwork

2. Puts the source hardware address in a filtertable and keeps track of which port the frame as received on

3. This information is what helps the machinedetermine the location of the specific sending device

4. The frames get forwarded only to the segmentwhere the destination hardware address is located

5. If the destination device is on the same segmentas the frame, the switch will block the segment from going to any othersegment. If the destination is on a different segment, the frame can betransmitted only to that segment (this is called transparent bridging)

5. If a frame with destination hardware address isn’tfound in the filter table, it will forward the frame to all connected segments 6. If the unknown device replies, the switch will updateits location in its table.

Front 30

Why is a switch said to be hardware based?

Back 30

Layer 2 switching is hardware-based, which means switches use application-specific integrated circuit (ASICs) to build and maintain filter tables (also known as MAC address tables or CAM tables).

Front 31

How does a router work?

Back 31

1. When a packet is received on a router interface,the destination IP will be checked

2. If the packet isn’t destined for that particularrouter, it will look up the packet’s destination network address in the routingtable. Once the router chooses an exit interface, the packet will be sent tothat interface to be framed, and sent out on the local network.

3. If the router can not find an entry for thepacket’s destination network in the routing table, it will drop the packet.