Interview Questions.

Q1. What Is Ethernet ?

Ethernet is a medium that is utilized by devices like computers, switches , routers, hubs and so on. If  gadgets needs to ship information among every other the use of ethernet era, both the gadgets must help ethernet. For instance, there are community interface playing cards which assist ethernet, switches and routers which aid ethernet network cards. Ethernet comes at the layer 2 of the OSI Model and Layer 1 of the TCP/IP Model.

Q2. How "late Collision" Is Avoided In Ethernet?

Late collision can be prevented, if the maximum period of the Ethernet network phase is constrained, such that if a collision occurs, it will reach the trmitter before the trmitter finished trmitting the entire body. In a typical 10 Mbps community, the minimum length of an Ethernet frame is 576 bits (seventy two bytes) and the most length of a single Ethernet community section is 2.5 kms.

Q3. What Is A "collision"?

At anybody example, in an Ethernet community, most effective one device can trmit. If  devices trmit at the same instance, then the indicators from each devices will collide and a "collision" will occur. When a "collision" occurs, the signals will get distorted and the frame will be lost. Collisions are very commonplace in a Ethernet network.

Q4. What Is Ethernet?

Ethernet is a Local Area Network (LAN) cabling and signaling specification for baseband networks. Ethernet makes use of a bus or superstar topology for connecting one-of-a-kind nodes in a community.

Q5. What Are The Standard Data Rates For Ethernet?

The standard statistics costs for Ethernet are 10 Mbps, a hundred Mbps, and 1 Gbps

Q6. What Are The Different Ethernet Frame Formats?

The special Ethernet frame codecs are listed underneath: Ethernet II and IEEE 802.Three

Q7. How To Differentiate Between An 802.3 Frame And An Ethernet Ii Frame?

The value of 'length' area in an 802.Three frame have to be less than 1500 and in a Ethernet II body the cost of 'type' area have to be greater than 15@Since the 802.Three body 'period' area and the Ethernet II body 'type' area are on the equal offset from the header, depending on the cost present, the body may be differentiated.

Q8. What Is Csma/cd?

CSMA/CD is a media access manipulate mechanism used in Ethernet to get over frame collision. The following steps are observed to recover from a collision. 

Step 1: Before an Ethernet device sends a frame at the Ethernet cable, it listens to discover if every other device is already trmitting a frame (Carrier Sense). 

Step 2: Once the tool unearths that different devices are not trmitting any frame, it starts trmitting the body. If two devices stumble on that the Ethernet cable is loose on the identical time, then each will begin trmitting the frames (Multiple Access). This will result in collision. 

Step 3: The Ethernet devices at the same time as trmitting the frames, additionally listen for the collision. (Collision Detect). 

Step four: If they hit upon a collision, both the devices stop sending the frame (backpedal). 

Step five: They retry the trmission after a logarithmic time-out length. This method is repeated until the body is trmitted efficaciously, for a most of sixteen times. The body is discarded after the sixteenth retry.

Q9. How Is "collision" Handled In Ethernet Networks?

Ethernet makes use of the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) media get right of entry to manage mechanism to locate and get over a collision.

Q10. What Are The Components Of An Ethernet Frame?

Ethernet frames are of various kinds. Typically they encompass the supply mac-cope with, vacation spot mac-address, facts from the upper layer, sort of statistics like IP, IPX and so forth, preamble (for clocking) and a FCS value for identifying the validity of the frame (Checks if the body is invalid, corrupt, and many others)

Q11. What Is The Minimum And Maximum Size Of An Ethernet Frame?

The minimal size of an Ethernet body is 64 bytes. The breakup of this length between the fields is: Destination Address (6 bytes) + Source Address (6 bytes) + Frame Type (2 bytes) + Data (46 bytes) + CRC Checksum (four bytes). The minimum variety of bytes handed as records in a body need to be forty six bytes. If the dimensions of the facts to be surpassed is much less than this, then padding bytes are introduced. The most size of an Ethernet frame is 1518 bytes. The breakup of this size between the fields is: Destination Address (6 bytes) + Source Address (6 bytes) + Frame Type (2 bytes) + Data (1500 bytes) + CRC Checksum (four bytes). The maximum variety of bytes of statistics that may be passed in a single body is 1500 bytes.

Q12. How Is A Frame Received At The Destination?

The preamble subject is seemed into first inner a body. This is only for synchronization. This is followed by means of the destination searching into whether the body is meant for itself or now not, by means of checking the vacation spot mac-cope with. Once the mac-cope with is confirmed, the FCS fee is calculated. If a mismatch is found , the frame is discarded. Else, the records form of the body is appeared into and the data is send to an appropriate layers of the running gadget (IP Layer).

Q13. What Is An Ethernet Frame ?

An ethernet body is used for encapsulating facts from the higher layers of the TCP/IP Model. Assume that a PC1 pings PC@The ping , that's an ICMP packet along with the IP Header is encapsulated within the ethernet frame. The body is used for sporting the ping packet and in the end deliver it to PC2.

Q14. What Is A Broadcast Address?

The Ethernet cope with in which all of the bits are 1 is known as a printed deal with. It is represented as FF:FF:FF:FF:FF:FF. A body with this address is received and processed with the aid of all the nodes within the network.

Q15. What Is Promiscuous Mode?

Normally, a Ethernet community interface will pass a body to the above network layers handiest if it's far addressed to that interface. If the network interface is placed in the promiscuous mode, the Ethernet community interface will ship all the frames (frames addressed to any host inside the community), regardless of their vacation spot address to the above network layers. This mode is utilized by network analyzers to seize all the frames.

Q16. How Two Systems In An Ethernet Network Communicate?

In a Ethernet community, a system proclaims the facts using a Ethernet frame. The vacation spot device is designated inside the Ethernet frame the usage of its Ethernet cope with. All the systems in the network concentrate for an Ethernet frame with their Ethernet deal with in it. When a gadget gets an Ethernet body with its deal with in it, it methods the body and sends it to the better layers (like IP) for further processing.

Q17. Why There Are Different Ethernet Frame Formats?

Xerox developed the first version of Ethernet, Ethernet I. The 2d model of Ethernet, Ethernet II, was developed by DEC, Intel and Xerox. After this the Ethernet changed into standardized via IEEE and the new layout is known as 802.Three layout. To offer backward compatibility with Ethernet II, 802.2 SNAP format was advanced.

Q18. What Is "overdue Collision"?

An Ethernet tool will stumble on a collision, at the same time as it's far trmitting, only if the collision reaches it earlier than it completes trmitting the whole frame. If the collision reaches the trmitter, after it completed sending the whole body, then the trmitter will now not stumble on the collision, it'll count on the collision came about due to some other body. This is called "late collision". Late collision will arise, if the length of the Ethernet community phase is more than the usual allowed period.

Q19. Why Sub Network Access Protocol (snap) Header Is Required?

The 802.2 LLC header replaces the 'protocol type' of the Ethernet II format with  SAP fields, Source SAP and Destination SAP. The cost of the SAP subject within the 802.2 header is equal to the 'protocol type' discipline within the Ethernet II header. The fee of the SAP discipline might be between 1 and 255, when you consider that it is an 8 bit subject. On the opposite hand, the 'protocol kind' cost for the usual protocols like IP, ARP, and so forth is grater than 15@Obviosuly, those values cannot be represented in the SAP fields. So to offer compatibility with Ethernet II, SNAP header changed into added to the 802.2 LLC header. In a SNAP frame, each the SAP values might be 0xAA and the primary five bytes of the facts will provide the protocol ID. Out of the 5 bytes of data, the final 2 bytes are identical as the protocol type area of the Ethernet II frame. The first 3 bytes are called as 'Organizationally Unique Identifer' (OUI) and are allocated as a supplier identifier. Typically, OUI may be zero.

Q20. How Is The Length Of An Ethernet Ii Frame Calculated?

The duration of an Ethernet II body isn't always gift inside the body itself. It depends on the Ethernet network interface used. When the interface sends a frame to the network device driving force, it materials the duration of the obtained body.

Q21. To Which Osi Layer Does Ethernet Belong?

Ethernet belongs to each the Physical Layer (Layer 1) and the Data Link layer (Layer 2) inside the OSI structure.

Q22. How Is An Ethernet Frame Constructed?

An ethernet body is constructed by way of the community card. When data at the running device , comes down to the community card, the frame could be constructed to send the records out at the network.

Q23. What Is Mtu?

Maximum Trmission Unit (MTU) is the most quantity of bytes that may be trmitted in a single trmission unit. Every conversation medium has a MTU. For Ethernet, the MTU of a frame is 1500.

Q24. What Is An Ethernet Address?

Each device in an Ethernet network is uniquely identified by means of a 48 bit (6 bytes) deal with called Ethernet deal with. Ethernet cope with is also referred to as Media Access Control (MAC) address. Ethernet addresses are represented as six pairs of hexadecimal digits separated by means of a colon. Ethernet deal with are buried within the network adapter through the manufacturer. A Ethernet cope with of a tool can't be changed. Example: 00:60:08:11:B1:AB, 00:00:c0:5e:eighty three:0e