Transmission Control Protocol in Java

Print QR Code in Java Transmission Control Protocol
Transmission Control Protocol
Encode QR Code 2d Barcode In Java
Using Barcode generation for Java Control to generate, create Denso QR Bar Code image in Java applications.
Figure 35-6: Retransmission due to a lost acknowledgment In a second scenario, host A sends two segments back to back The first segment has sequence number 92 and 8 bytes of data, and the second segment has sequence number 100 and 20 bytes of data Suppose that both segments arrive intact at B, and B sends two separate acknowledgements for each of these segments The first of these acknowledgements has acknowledgment number 100; the second has acknowledgment number 120 Suppose now that neither of the acknowledgements arrive at host A before the timeout of the first segment When the timer expires, host A resends the first segment with sequence number 92 Now, you may ask, does A also resend second segment According to the rules described above, host A resends the segment only if the timer expires before the arrival of an acknowledgment with an acknowledgment number of 120 or greater Thus, as shown in Figure 35-7, if the second acknowledgment does not get lost and arrives before the timeout of the second segment, A does not resend the second segment
Creating Barcode In Java
Using Barcode printer for Java Control to generate, create barcode image in Java applications.
Figure 35-7: Segment is not retransmitted because its acknowledgment arrives before the timeout In a third and final scenario, suppose host A sends the two segments, exactly as in the second example The acknowledgment of the first segment is lost in the network, but just before the timeout of the first segment, host A receives an acknowledgment with acknowledgment number 120 Host A therefore knows that host B has received everything up through byte 119; so host A does not resend either of the two segments This scenario is illustrated in the Figure 35-8
Read Barcode In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
file:///D|/Downloads/Livros/computa o/Computer%20Net%20Approach%20Featuring%20the%20Internet/segmenthtml (8 of 15)20/11/2004 15:52:11
Painting QR Code In Visual C#
Using Barcode generation for .NET framework Control to generate, create Quick Response Code image in Visual Studio .NET applications.
Transmission Control Protocol
Drawing QR Code ISO/IEC18004 In Visual Studio .NET
Using Barcode drawer for ASP.NET Control to generate, create QR Code ISO/IEC18004 image in ASP.NET applications.
Figure 35-8: A cumulative acknowledgment avoids retransmission of first segment Recall that in the previous section we said that TCP is a Go-Back-N style protocol This is because acknowledgements are cumulative and correctlyreceived but out-of-order segments are not individually ACKed by the receiver Consequently, as shown in Figure 35-5 (see also Figure 34-11), the TCP sender need only maintain the smallest sequence number of a transmitted but unacknowledged byte (sendbase) and the sequence number of the next byte to be sent (nextseqnum) But the reader should keep in mind that although the reliable-data-transfer component of TCP resembles Go-Back-N, it is by no means a pure implementation of Go-Back-N To see that there are some striking differences between TCP and Go-Back-N, consider what happens when the sender sends a sequence of segments 1, 2,, N, and all of the segments arrive in order without error at the receiver Further suppose that the acknowledgment for packet n < N gets lost, but the remaining N-1 acknowledgments arrive at the sender before their respective timeouts In this example, Go-Back-N would retransmit not only packet n, but also all the subsequent packets n+1, n+2,,N TCP, on the other hand, would retransmit at most one segment, namely, segment n Moreover, TCP would not even retransmit segment n if the acknowledgement for segment n+1 arrives before the timeout for segment n There have recently been several proposals [RFC 2018, Fall 1996, Mathis 1996] to extend the TCP ACKing scheme to be more similar to a selective repeat protocol The key idea in these proposals is to provide the sender with explicit information about which segments have been received correctly, and which are still missing at the receiver
QR Code Printer In .NET Framework
Using Barcode creation for .NET framework Control to generate, create QR Code 2d barcode image in VS .NET applications.
356 Flow Control
Creating QR Code In Visual Basic .NET
Using Barcode printer for .NET framework Control to generate, create QR Code 2d barcode image in .NET applications.
Recall that the hosts on each side of a TCP connection each set aside a receive buffer for the connection When the TCP connection receives bytes that are correct and in sequence, it places the data in the receive buffer The associated application process will read data from this buffer, but not necessarily at the instant the data arrives Indeed, the receiving application may be busy with some other task and may not even attempt to read the data until long after it has arrived If the application is relatively slow at reading the data, the sender can very easily overflow the connection's receive buffer by sending too much data too quickly TCP thus provides a flow control service to its applications by eliminating the possibility of the sender overflowing the receiver's buffer Flow control is thus a speed matching service - matching the rate at which the sender is seding to the rate at which the receiving application is reading As noted earlier, a TCP sender can also be throttled due to congestion within the IP network; this form of sender control is referred to as congestion control, a topic we will explore in detail in Sections 36 and 37 While the actions taken by flow and congestion control are similar (the throttling of the sender), they are obviously taken for very different reasons Unfortunately, many authors use the term interchangeably, and the savvy reader would be careful to distinguish between the two cases Let's now discuss how TCP provides its flow control service TCP provides flow control by having the sender maintain a variable called the receive window Informally, the receive window is used to give the sender an idea about how much free buffer space is available at the receiver In a full-duplex connection, the sender at each side of the connection maintains a distinct receive window The receive window is dynamic, ie, it changes throughout a connection's lifetime Let's investigate the receive window in the context of a file transfer Suppose that host A is sending a large file to host B over a TCP connection Host B allocates a receive buffer to this connection; denote its size by RcvBuffer From time to time, the application process in host B reads from the buffer Define the following variables: LastByteRead = the number of the last byte in the data stream read from the buffer by the application process in B LastByteRcvd = the number of the last byte in the data stream that has arrived from the network and has been placed in the receive buffer at B
Bar Code Drawer In Java
Using Barcode generation for Java Control to generate, create barcode image in Java applications.
file:///D|/Downloads/Livros/computa o/Computer%20Net%20Approach%20Featuring%20the%20Internet/segmenthtml (9 of 15)20/11/2004 15:52:11
Barcode Creation In Java
Using Barcode creation for Java Control to generate, create barcode image in Java applications.
UPC A Creator In Java
Using Barcode encoder for Java Control to generate, create UPC-A image in Java applications.
Code 3 Of 9 Creator In Java
Using Barcode creator for Java Control to generate, create Code 3/9 image in Java applications.
Paint Bar Code In .NET
Using Barcode creation for ASP.NET Control to generate, create barcode image in ASP.NET applications.
Reading Barcode In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
EAN13 Printer In .NET
Using Barcode printer for ASP.NET Control to generate, create UPC - 13 image in ASP.NET applications.
Code-39 Generation In .NET Framework
Using Barcode printer for ASP.NET Control to generate, create Code-39 image in ASP.NET applications.