What is duplex printing ?

                                    What is duplex printing ?

Duplex printing is a feature of some computer printers and multi-function printers (MFPs) that allows the printing of a sheet of paper on both sides automatically. Print devices without this capability can only print on a single side of paper, sometimes called single-sided printing or simplex printing.

Duplex print devices, depending on options, software, and printer settings, can print single-sided page to single-sided page (1:1) or double-sided page to double-sided page (2:2). Many can also combine single-sided pages into a double-sided page format (1:2). Double-sided booklet formats (2:2 with a center fold) are also available, depending on optional outputs from the printer.

Duplexed documents can be printed to be bound on either the short edge or the long edge. This functionality is mostly available on printers that come with a duplexer.^[1] Long edge binding in portrait mode allows pages to be turned side-to-side like a book. Short-edge binding allows the pages to be oriented correctly if they are flipped vertically, as in a notepad. This second form of printing/binding is sometimes known as "tumble." If the printing is done in landscape mode, these concepts are transposed since the print direction is different.

Single-sided printers can print both sides of the paper by manually removing and turning over a stack of sheets after one side is printed; however, the user has to manually turn the print job over and re-initialize the printing of the document, with care to ensure that the order and orientation is correct.

Duplex

Duplex

It is important that you understand duplex logic and how it affects traffic on a network. The communication mode of a device may either be half-duplex or full-duplex, depending on the connection type.

Half-duplex allows for one-way communication, which means that a device can only send or receive a data transmission at any given time. This option does not allow for simultaneously sending and receiving data. As part of a shared collision domain, hubs are inherently set up for half-duplex. Bandwidth suffers because a collision detection technology such as the CSMA/CD algorithm must be implemented. Collision detection can chew up 50–60% of the bandwidth on that ethernet LAN.

Full-duplex allows for two-way communication, which means that a device can simultaneously send and receive data transmissions. Full-duplex is available with dedicated switch port connections to a single device. If a switch port connection is configured for full-duplex, the CSMA/CD algorithm must be disabled. An ethernet connection set for full-duplex allows for 100% transmission speeds in both directions. For example, a 100Mbps connection can transmit data simultaneously at 100Mbps in each direction.

With ethernet, if a switch port and NIC offer multiple speed options as well as half- and full-duplex settings, autonegotiation can be configured on both devices. The switch and NIC automatically negotiate the connection speed and duplex so that the settings on both ends match. You may have heard of a 10/half or 100/full connection before. The term 10/half refers to a 10Mbps half-duplex connection. It is more likely that you will see 100/full, which indicates a 100Mbps full-duplex connection.

Top Questions and Answers on OSI Model

• List the layers of OSI?

From top to bottom, OSI layers are,

Application, Presentation, Session, Transport, Network, Data Link and Physical.

• What are the responsibilities of Data Link Layer?

Framing, Error detection, CRC and Physical Addressing is the task of DLL.

• What are the responsibilities of Network Layer?

Routing, IP Addressing and Path determination are the main responsibilities of Network Layer.

• What are the responsibilities of Transport Layer?

Transport Layer has a lot of function. Most important being,

1. Multiplexing and De-Multiplexing
2. Segmentation and Re-assembly
3. Flow Control
4. Error Correction
5. Connection Establishment
6. Sequencing
7. Acknowledgement
8. 3 way Handshake

• Routers work at which OSI layer?

Network Layer

• Switches work at which OSI layer?

Layer 2 and Some Switches can operate at Layer 3 and above

• What is a Window in networking terms?

Window is the amount of segments sent by TCP between two acknowledgements.

• What is the role of the LLC sublayer in datalink layer?

Logical Link Control provides error detection, using Ethernet trailer field frame check sequence (FCS).

• What is the function of the Application Layer in networking?

Application Layer is responsible for providing a user interface in between user and Network with the help of applications like web browsers.

• What is the difference between TCP and UDP?

Following are differences in TCP and UDP,

• TCP stands for “Transmission Control Protocol” UDP stands for “User datagram Protocol”.
• TCP is connection oriented protocol while UDP is connectionless protocol.
• TCP is more reliable than UDP.
• UDP is faster for data sending than TCP.
• UDP makes error checking but no reporting but TCP checks for errors and performs reporting.
• TCP provides guaranteed Delivery of Data but UDP has no guarantee.
• Header size of TCP is 20 bytes while that of UDP is 8 bytes.
• TCP has acknowledgement segments but UDP has no acknowledgement.
• TCP is used for application that require high reliability but less time critical whereas UDP is used for application that are time sensitive but require less reliability.

• What is the port no of DNS and Telnet?

DNS = 53, Telnet = 23

• Which service use both TCP and UDP ?

DNS uses both TCP and UDP

• What is the port no of SMTP and POP3?

POP3 = 110; SMTP = 25

• In which layer term “Frames” is used ?

Frames are PDU of Data Link Layer

• In which layer term “Packets” is used ?

Packets are PDU of Network Layer

• In which layer term “Segments” is used ?

Segments are used at Transport Layer

• Give some example for protocols work at Application layer ?

Application Layer Protocols are  HTTP, HTTPs, Telnet, SSH, DNS, FTP, TFTP, DHCP, RIP

• What is CRC? Which layer CRC works ?

Cyclic Redundancy Check is used to detect the errors in network. It works at Data Link Layer (LLC Sub Layer).

• What is the purpose of the Data Link?

Data Link Layer is responsible for Framing, Error Detection and Physical Addressing

• Which one is reliable – TCP or UDP ?

TCP is reliable.

• What is the port number of ftp (data) and ftp?

FTP port number 20 (Data); 21 for Control

• Which layer provides logical addressing that routers will use for path determination ?

Network Layer

• Which layer specifies voltage, wire speed, and pinout cables and moves bits between devices ?

Physical

• Which layer combines bits into bytes and bytes into frames, uses MAC addressing, and provide error detection ?

Data Link Layer

• Which layer is responsible for keeping the data from different applications separate on the network ?

Session layer.

• Which layer segments and resembles data into a data stream ?

Transport layer.

• Which layer provides the physical transmission sof the data and handless error notification, network topology, and flow control ?

Data Link Layer

• Which Layer manages device addressing, tracks the location of devices on the network, and determine the best way to move data ?

Network layer.

• How Data breaks down on each layer from top to bottom ?

Encapsulation occurs in following format

• MAC address works on which layer ? What are the differences of MAC sublayer and LLC sublayer?

MAC works at DATA LINK LAYER. Media Access Control provides physical addressing while Logical Link Control provides error detection, using Ethernet trailer field frame check sequence (FCS). It is 4 bytes field. When a sending device sends a data it put the data in a mathematical algorithm and it gets a product, sending device puts the product in FCS. When a receiving device receive a data it also put the data in same mathematical algorithm and get a product. If both products are same, Frame is accepted or else discarded.

• Which layer is responsible for converting data packets from the Data Link layer into electrical signals ?

Physical Layer

• At which layer is routing implemented, enabling connections and path selection between two end systems. ?

Network Layer

• Which layer defines how data is formatted, presented, encoded,and converted for use on the network ?

Presentation Layer

• Which layer is responsible for creating, managing and terminating sessions between applications ?

Session Layer

• DNS uses which protocol? Why?

DNS uses both TCP and UDP

• Which layer is closer to the user?

From sender point of view, Application Layer is closest and from Receiver point of view Pgysical Layer is closest.

• Differentiate between forward lookup and reverse lookup in DNS?

Forward Lookup: Name to IP resolution

Reverse Lookup: IP to Name resolution;

• What is IPSec?

IPSec provides data security at the IP Packet Level.

• What is the way to establish a TCP connection?

TCP Connection is established using three-way Handshake.

• What is the difference between flow control and error control?

Error Controls the process of detecting and correcting both the bit and packet level error. While flow control is a mechanism to ensure the efficient delivery of Data. Flow control is agreeing on the minimum amount of data that a receiver can handle at a time.