ensuring the reliability of data delivery © 2004 cisco systems, inc. all rights reserved....
TRANSCRIPT
Ensuring the Reliability of Data Delivery
© 2004 Cisco Systems, Inc. All rights reserved.
Understanding How UDP and TCP Work
INTRO v2.0—6-1
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-2
Outline
• Overview
• Transport Layer Functions
• Reliable vs. Best Effort
• UDP and TCP
• UDP and TCP Port Numbers
• UDP and TCP Header Formats
• Summary
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-3
Transport Layer
• Session multiplexing
• Segmentation
• Flow control (when required)
• Connection-oriented (when required)
• Reliability (when required)
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-4
Reliable vs. Best Effort Comparison
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-5
TCP/IP Protocol Stack
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-6
UDP Characteristics
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-7
TCP Characteristics
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-8
Port Numbers
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-9
UDP Header
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-10
TCP Header
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-11
Summary
• The transport layer operates between the network layer and the application layer and provides communication services directly to the application processes running on different hosts.
• UDP is a best-effort, connectionless protocol used for applications that do not require error checking or sequence numbering, such as voice and video streaming.
• TCP is a reliable, connection-oriented protocol that ensures delivery of packets without error and in correct order.
© 2004 Cisco Systems, Inc. All rights reserved. INTRO v2.0—6-12
Summary (Cont.)
• UDP and TCP use ports to support multiple conversations between different network devices.
• UDP delivers TFTP, SNMP, and RIP.
• TCP delivers FTP, Telnet, and SMTP.
• The UDP header length is always 64 bits.
• The TCP header follows the Internet header, supplying information specific to the TCP protocol. This division allows for the existence of host level protocols other than TCP.
