Answer / shahin

CSMA/CD (Carrier Sense Multiple Access/Collision
Detection)is media-access mechanism is what keeps networks
running.

If two or more computers transmit data at the same time, we
get data collision. And thus, no data is sent or received.

We have CSMA/CD for both preventing and controlling collisions.

Suppose 4 system connected as on bus topology or connected
on a Hub.

As we know, in Hub one collision domain & one broadcast
domain. More simply, Hub port just copied data wat it
received & paste it on the rest of the port apart from dat
port from where hub received this data.

So how its detects collision...

Before sending any data, Ethernet NIC first test the voltage
of the line. If its normal, i mean voltage level on line its
start sending data. (Specific voltage level value i didn't
remember).

If two NIC test this voltage level at the same time & they
found its normal for start sending data. When they send
data, data will collide somewhere in the line. Hence data
lose occur & delay in communication.

When NIC detects collision, they wait for random period of
time. (Time i didn't remember). After certain time period
they test the line again & if they found normal. they will
start sending data.

Note: CSMA/CD is not used on Full Duplex Ethernet networks.


3rd Question:

As far my knowledge, there is no such specific command for
this. But we can make any full duplex line in to half duplex
also.

Router(config)#interface fastethernet 0/0
Router(config-if)#duplex ?
auto Enable AUTO duplex configuration
full Force full duplex operation
half Force half-duplex operation



Buddy, i can say this much about it. Hope it may help u
little bit..!!!

Thankx for nice question.

Whith the hierarchical numbering of IP addressing what determines the spoon of the address that will identify the network number? A. subnet mask B. dots between octets C. class of the first octet D. assignments of DHCP E. address resolution process

1 Answers  

---

What are the two types of transmission technology available in ccna?

1 Answers  

---

Identify the default IPX serial encapsulation? A.) Novell-Ether B.) SDLC C.) SNAP D.) HDLC

1 Answers  

---

On an ISDN BRI interface, the control channel is the 'D' channel. What is the rate of this channel? A.) 64 Kbps B.) 1.544 Mbps C.) 128 Kbps D.) 2.048 Mbps E.) 16 Kbps

4 Answers  

---

Which of the following are Session Layer standards? A.) ASCII and EBCDIC B.) MPEG and MIDI C.) NFS and SQL D.) JPEG and PICT

2 Answers  

---

Which protocol will let neighbor routers know if your internetwork experienced congestion on a serial port? A.) BootP B.) IP C.) ICMP D.) ARP E.) FTP F.) RARP

1 Answers  

---

What are the steps of conversion for data encapsulation?

0 Answers  

---

Identify the command to configure the router to boot from an alternate IOS located in flash? A.) boot system flash IOS.exe B.) boot system tftp IOS.exe 172.16.5.1 C.) boot system alternate IOS.exe D.) boot system rom IOS.exe

1 Answers  

---

Which cable called roll-over?

0 Answers  

---

Explain the difference between routable and non- routable protocols?

0 Answers  

---

What is etherchannel?

0 Answers  

---

Identify 3 characteristics regarding CDP? A.) On by default B.) Shows only directly connected neighbors C.) Requires IP or IPX D.) 60 second update interval by default E.) 30 second updates interval by default

1 Answers  

---