What Is The Difference Between Udp And Tcp Internet Protocols?

What is the difference between UDP and TCP internet protocols? Q. Can you explain the difference between UDP and TCP internet protocol (IP) traffic and its usage with an example? A. Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)is a transportation protocol that is one of the core protocols of the Internet protocol suite. Both TCP and UDP work at transport layer TCP/IP model and both have very different usage.

Difference between TCP and UDP TCP UDP Reliability: TCP is connectionReliability: UDP is connectionless oriented protocol. When a file or protocol. When you a send a data or message send it will get delivered message, you don't know if it'll get unless connections fails. If connection there, it could get lost on the way. lost, the server will request the lost There may be corruption while part. There is no corruption while transferring a message. transferring a message. Ordered: If you send two messages Ordered: If you send two messages along a connection, one after the out, you don't know what order they'll other, you know the first message will arrive in i.e. no ordered get there first. You don't have to worry about data arriving in the wrong order. Heavyweight: - when the low level Lightweight: No ordering of parts of the TCP "stream" arrive in the messages, no tracking connections, wrong order, resend requests have to etc. It's just fire and forget! This be sent, and all the out of sequence means it's a lot quicker, and the parts have to be put back together, so network card / OS have to do very requires a bit of work to piece little work to translate the data back together. from the packets. Streaming: Data is read as a "stream," Datagrams: Packets are sent with nothing distinguishing where one individually and are guaranteed to be packet ends and another begins. There whole if they arrive. One packet per may be multiple packets per read call. one read call. Examples: World Wide Web (Apache Examples: Domain Name System TCP port 80), e-mail (SMTP TCP (DNS UDP port 53), streaming media port 25 Postfix MTA), File Transfer applications such as IPTV or movies, Protocol (FTP port 21) and Secure Voice over IP (VoIP), Trivial File Shell (OpenSSH port 22) etc. Transfer Protocol (TFTP) and online multiplayer games etc TCP - Transfer Control Protocol. a.Reliable b.Connection oriented. c.Acknowledgement

UDP - User Datagram Protocol. a.Non Reliable b.Connectionless c.No Acknowledgement

User Datagram Protocol (UDP) It is part of the base protocols of the Internet Protocol Suite. Programs on networked computers can send short messages sometimes called as datagrams. UDP does not guarantee any reliability( it happens datagram may arrive out of order, are duplicated, or are missing without any notice). The fact that no checking whether all packets are actually delivered is made, UDP proves to be faster and more efficient, for applications that do not need guaranteed delivery. UDP find its uses in such situations: Time-sensitive applications. The problems due to delayed packets are avoided It is also useful for servers that answer small queries from huge numbers of clients. UDP supports packet broadcast (conveys to all on local network) and multicasting (conveys to all subscribers).

Transmission Control Protocol (TCP) It is often referred to as TCP/IP due to the importance of this protocol in the Internet Protocol Suite. TCP operates at a higher level, concerned only with the two end systems, (e.g. between web browser and a web server). TCP provides reliable, sequential delivery of a stream of data from one program on one computer to another program on another computer. Common uses of TCP regroup e-mailing support and file transfer and Web applications. Among its management tasks, TCP controls message size, the rate at which messages are exchanged, and network traffic congestion. As for IP, it handles lower-level transmissions from computer to computer as a message transferred across the Internet. Note: IP works by exchanging information chunks called packets. A packet is a sequence of bytes consisting of a header and a body. The header contains the packet's destination and path to be taken on the Internet and the body contains the data which is being transmitted.

- Round-trip time (RTT), also called round-trip delay, is the time required for a signal pulse or packet to travel from a specific source to a specific destination and back again. In this context, the source is the computer initiating the signal and

the destination is a remote computer or system that receives the signal and retransmits it.

Go-Back-N ARQ is a specific instance of the Automatic Repeat-reQuest (ARQ) Protocol, in which the sending process continues to send a number of frames specified by a window size even without receiving an ACK packet from the receiver. The receiver process keeps track of sequence number of the next frame it expects to receive, and sends that number with every ACK it sends. The receiver will ignore any frame that does not have the exact sequence number it expects -- whether that frame is a "past" duplicate of a frame it has already ACK'ed, or whether that frame is a "future" frame past the lost packet it is waiting for. Once the sender has sent all of the frames in its window, it will detect that all of the frames since the first lost frame are outstanding, and will go back to sequence number of the last ACK it received from the receiver process and fill its window starting with that frame and continue the process over again. A nice java applet can be found here: http://media.pearsoncmg.com/aw/aw_kurose_network_2/applets/go-back-n/go-back-n.html Go-Back-N ARQ Go-Back-N ARQ is a specific instance of the Automatic Repeat-reQuest (ARQ) Protocol, in which the sending process continues to send a number of frames specified by a window size even without receiving an ACK packet from the receiver. The receiver process keeps track of sequence number of the next frame it expects to receive, and sends that number with every ACK it sends. The receiver will ignore any frame that does not have the exact sequence number it expects -- whether that frame is a "past" duplicate of a frame it has already ACK'ed [1] or whether that frame is a "future" frame past the lost packet it is waiting for. Once the sender has sent all of the frames in its window, it will detect that all of the frames since the first lost frame are outstanding, and will go back to sequence number of the last ACK it received from the receiver process and fill its window starting with that frame and continue the process over again. Go-Back-N ARQ is a more efficient use of a connection than Stop-and-wait ARQ, since unlike waiting for an acknowledgement for each packet, the connection is still being utilized as packets are being sent. In other words, during the time that would otherwise be spent waiting, more packets are being sent. However, this method also results in sending frames multiple times -- if any frame was lost or damaged, or the ACK acknowledging them was lost or damaged, then that frame and all following frames in the window (even if they were received without error) will be re-sent. To avoid this, Selective Repeat ARQ can be used. [2] Contents: 1. Pseudocode 2. Choosing a Window size(N) 3. Examples 4. References 5. External links

1. Pseudocode

These examples assume an infinite amount of sequence and request numbers. [3] N = windowsize Rn = request number Sn = sequence number Sb = sequence base Sm = sequence max Receiver: Rn = 0 Do the following forever: If the packet received = Rn && the packet is error free Accept the packet and send it to a higher layer Rn = Rn +1 Send a Request for Rn Else Refuse packet Send a Request for Rn Sender: Sb = 0 Sm = N - 1 Repeat the following steps forever: 1. If you receive a request number where Rn > Sb Sm = Sm + (Rn - Sb) Sb =Rn 2. If no packet is in transmission, Transmit a packet where Sb <= Sn <= Sm. Packets are transmitted in order.

2. Choosing a Window size(N) There are a few things to keep in mind when choosing a value for N. 1. The sender must not transmit too fast. N should be bounded by the receiver’s ability to process packets. 2. N must be smaller than the number of sequence numbers (if they are numbered from zero to n1) to verify transmission in cases of any packet (any data or ACK packet) being dropped. [4] 3. Given the bounds presented in (1) and (2), choose N to be the largest number possible. [5] What is the difference between flow control and congestion control? Where can I find more information on this? > TCP's four congestion control algorithms include: slow start, congestion avoidance, fast retransmit, and fast recovery. Congestion control basically states that a network device can transmit only a certain number of packets and can not add more packets to a network until an acknowledgement is received. http://www.ecse.rpi.edu/Homepages/shivkuma/research/congpapers.html has some good papers on the topic. Flow control works by refusing new connections until congestion is resolved. In serial transmissions, Xon/Xoff is used for flow control. It is a handshaking mechanism that will keep a sender from sending data faster than a receiver can receive it. Flow control vs. congestion control: Flow control means preventing the source from sending data that the sink will end up dropping because it runs out of buffer space. This is fairly easy with a sliding window protocol--just make sure the source's window is no larger than the free space in the sink's buffer. TCP does this by letting the sink advertise its free buffer space in the window field of the acks. Congestion control means preventing (or trying to prevent) the source from sending data that will end up getting dropped by a router because its queue is full. This is more complicated, because packets from different sources travelling different paths can converge on the same queue.

What is a Subnet Mask? A subnet mask allows you to identify which part of an IP address is reserved for the network, and which part is available for host use. If you look at the IP address alone, especially now with classless interdomain routing, you can't tell which part of the address is which. Adding the subnet mask, or netmask, gives you all the information you need to calculate network and host portions of the address with ease. In summary, knowing the subnet mask can allow you to easily calculate whether IP addresses are on the same subnet, or not.

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Acc ordi ng to Forr est er, "Go ogl e is setti ng a new pric e floo r on em ail and arc hivi ng cost s." Do wnl oad the Last modified: Tuesday, January 15, 2008 Forr est A mask used to determine er rep what subnet an IP address ort belongs to. An IP address co has two components, the mp arin network address and the g host address. For example, the cost consider the IP address 150.215.017.009. Assuming this is part of a Class B network, the first two numbers (150.215)semof represent the Class B network address, and the second two numbers (017.009) identify a ail fro particular host on this network. m Subnetting enables the network administrator to further divide the host part of the address intoGo ogl two or more subnets. In this case, a part of the host address is reserved to identify the particular e subnet. This is easier to see if we show the IP address in binary format. The full address is: and oth er pro vide rs. >>

subnet mask

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10010110.11010111.00010001.00001001 The Class B network part is: 10010110.11010111 and the host address is 00010001.00001001 If this network is divided into 14 subnets, however, then the first 4 bits of the host address (0001) are reserved for identifying the subnet. The subnet mask is the network address plus the bits reserved for identifying the subnetwork. (By convention, the bits for the network address are all set to 1, though it would also work if the bits were set exactly as in the network address.) In this case, therefore, the subnet mask would be 11111111.11111111.11110000.00000000. It's called a mask because it can be used to identify the subnet to which an IP address belongs by performing a bitwise AND operation on the mask and the IP address. The result is the subnetwork address: Subnet Mask IP Address Subnet Address

255.255.240.000 150.215.017.009 150.215.016.000

11111111.11111111.11110000.00000000 10010110.11010111.00010001.00001001 10010110.11010111.00010000.00000000

The subnet address, therefore, is 150.215.016.000.

subnet mask A mask used to determine what subnet an IP address belongs to. An IP address has two components, the network address and the host address. For example, consider the IP address 150.215.017.009. Assuming this is part of a Class B network, the first two numbers (150.215) represent the Class B network address, and the second two numbers (017.009) identify a particular host on this network. Subnetting enables the network administrator to further divide the host part of the address into two or more subnets. In this case, a part of the host address is reserved to identify the particular subnet. This is easier to see if we show the IP address in binary format. The full address is: 10010110.11010111.00010001.00001001 The Class B network part is: 10010110.11010111 and the host address is 00010001.00001001 If this network is divided into 14 subnets, however, then the first 4 bits of the host address (0001) are reserved for identifying the subnet. The subnet mask is the network address plus the bits reserved for identifying the subnetwork. (By convention, the bits for the network address are all set to 1, though it would also work if the bits were set exactly as in the network address.) In this case, therefore, the subnet mask would be 11111111.11111111.11110000.00000000. It's called a mask because it can be used to identify the subnet to which an IP address belongs by performing a bitwise AND operation on the mask and the IP address. The result is the subnetwork address:

Subnet Mask IP Address Subnet Address

255.255.240.000 150.215.017.009 150.215.016.000

11111111.11111111.11110000.00000000 10010110.11010111.00010001.00001001 10010110.11010111.00010000.00000000

The subnet address, therefore, is 150.215.016.000.