TCP IP Illustrated

The host requirements rfc states that tcp should

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Unformatted text preview: t's possible for it to send the first byte (the ASCII ESC) and then hold the remaining bytes of the sequence waiting for the ACK of this byte. But when the server receives this first byte it doesn't generate an echo until the remaining bytes are received. This often triggers the delayed ACK algorithm on the server, meaning that the remaining bytes aren't sent for up to 200 ms. This can lead to noticeable delays to the interactive user. file:///D|/Documents%20and%20Settings/bigini/Docum...i/homenet2run/tcpip/tcp-ip-illustrated/tcp_int.htm (7 of 14) [12/09/2001 14.47.18] Chapter 19. TCP Interactive Data Flow The sockets API uses the TCP_NODELAY socket option to disable the Nagle algorithm. The Host Requirements RFC states that TCP should implement the Nagle algorithm but there must be a way for an application to disable it on an individual connection. An Example We can see this interaction between the Nagle algorithm and keystrokes that generate multiple bytes. We establish an Rlogin connection from our host slip to the host vangogh.cs.berkeley.edu. We then type the Fl function key, which generates 3 bytes: an escape, a left bracket, and an M. We then type the F2 function key, which generates another 3 bytes. Figure 19.5 shows the tcpdump output. (We have removed the type-of-service information and the window advertisements.) 1 2 3 4 5 0.0 0.250520 (0.2505) 0.251709 (0.0012) 0.490344 (0.2386) 0.588694 (0.0984) 2.836830 (2.2481) 3.132388 7 (0.2956) 3.133573 8 (0.0012) 3.370346 9 (0.2368) 3.388692 10 (0.0183) 6 type Fl key slip.1023 > vangogh. login: P 1:2(1) ack 2 vangogh.login > slip.1023: P 2:4(2) ack 2 slip.1023 > vangogh.login: P 2:4(2) ack 4 vangogh.login > slip.1023: P 4:6(2) ack 4 slip.1023 > vangogh.login: . ack 6 type F2 key slip.1023 > vangogh.login: 6 vangogh.login > slip.1023: 5 slip.1023 > vangogh.login: 8 vangogh.login > slip.1023: 7 P 4:5(1) ack P 6:8(2) ack P 5:7(2) ack P 8:10(2) ack slip.1023 > vangogh.login: . ack 10 Figure 19.5 Watching the...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.

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