nov-03 ©cisco systems ccna semester 1 version 3 comp11 mod11 – st. lawrence college – cornwall...
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Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 1
Cisco Systems CCNA Version 3 Semester 1
Module 11
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 2
Students completing this module should be able to:
• Describe the functions of the TCP/IP transport layer. • Describe flow control. • Describe the processes of establishing a connection
between peer systems. • Describe windowing. • Describe acknowledgment. • Identify and describe transport layer protocols. • Describe TCP and UDP header formats. • Describe TCP and UDP port numbers. • List the major protocols of the TCP/IP application layer. • Provide a brief description of the features and operation of
well-known TCP/IP applications.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 3
The Department of Defense (DoD) developed the TCP/IP reference model to provide a communication network that could continue to function in wartime.
Transport Layer
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 4
OVERVIEW11.1 TCP/IP Transport Layer
11.1.1 Introduction to transport layer
11.1.2 Flow control
11.1.3 Session establishment, maintenance, and termination overview
11.1.4 Three-way handshake
11.1.5 Windowing
11.1.6 Acknowledgment
11.1.7 Transmission Control Protocol (TCP)
11.1.8 User Datagram Protocol (UDP)
11.1.9 TCP and UDP port numbers
11.2 The Application Layer11.2.1 Introduction to the TCP/IP application layer
11.2.2 DNS
11.2.3 FTP
11.2.4 HTTP
11.2.5 SMTP
11.2.6 SNMP
11.2.7 Telnet
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 5
11.1.1 Introduction to transport layer
•Segmentation of upper-layer application data •Establishment of end-to-end operations •Transport of segments from one end host to another end host •Flow control provided by sliding windows •Reliability provided by sequence numbers and acknowledgments
MACd MACs IPs IPd Ps Pd
Ps Pd
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 6
MACd MACs
IPs IPd
Ps Pd
• Reliable• connection-
oriented
11.1.1 Introduction to transport layer
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 7
11.1.1 Introduction to transport layer
• Peer to Peer Communication is really communication between the headers at each layer.
• Layers 2 and 3 are best effort or connectionless.• Layer 4 Transport is connection oriented. The ‘connection’ is in the
header.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 8
11.1.1 Introduction to transport layer
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 9
11.1.2 Flow control
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 10
11.1.1 Introduction to transport layer
• There may be more than one application using the TCP/IP stack at the same time.
• Port Numbers are used to keep them separate.
HTTP 80 HTTP 80
TELNET 23 TELNET 23
SMTP 25 SMTP 25
DNS 53 DNS 53
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 11
11.1.3 Session establishment, maintenance, and termination overview
HTTPTELNETDNS53 23 80
TELNET
23
FTP
21
Congestion can be caused by:• Faster computers generate traffic volume greater than the network is able to transfer. • Large numbers of computers send data to the same location at the same time.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 12
11.1.3 Session establishment, maintenance, and termination overview
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 13
11.1.3 Session establishment, maintenance, and termination overview
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 14
11.1.4 Three-way handshake
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 15
In TCP the three-way handshaking process begins when the sending host sends a SYN
segment.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 16
11.1.5 Windowing
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 17
11.1.6 Acknowledgment
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 18
6603 – 6267 = 336 bytes or octets
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 19
11.1.5 Windowing
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 20
I can accept a window this
big.
Source Port = 80. my Host.
Destination Port = 3551. Marc’s server.
Window size is the size in Octets or Bytes that the device with the Source Port Transport Layer buffer is ready to accept.
This is Flow Control.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 21
11.1.6 Acknowledgment
The source must receive an "ACK 4" acknowledgement
before sending more data.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 22
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 23
11.1.7 Transmission Control Protocol (TCP)
567 bytes or octets of data.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 24
567 bytes or octets of data.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 25
In TCP the three-way handshaking process
begins when the sending host sends a SYN segment.
Source = 3550Destination = 80
1
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 26
The Destination ACK…
Source = 80Destination =
3550
… and requests a SYN of its
own.
2
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 27
The Source acknowledges.
Source = 3550Destination = 80
3
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 28
• Source port – Number of the calling port
• Destination port – Number of the called port
• Sequence number – Number used to ensure correct sequencing of the arriving data
• Acknowledgment number – Next expected TCP octet
• HLEN – Number of 32-bit words in the header
• Reserved – Set to zero
• Code bits – Control functions, such as setup and termination of a session
• Window – Number of octets that the sender is willing to accept
• Checksum – Calculated checksum of the header and data fields
• Urgent pointer – Indicates the end of the urgent data
• Option – One option currently defined, maximum TCP segment size
• Data – Upper-layer protocol data
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 29
11.1.8 User Datagram Protocol (UDP)
• no guaranteed delivery of datagrams • reliability provided by the application layer • connectionless
• Source port – Number of the calling port • Destination port – Number of the called port • Length – Number of bytes including header and data • Checksum – Calculated checksum of the header and data
fields • Data – Upper-layer protocol data
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 30
11.1.9 TCP and UDP port numbers
You should at least remember these port numbers.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 31
11.1.9 TCP and UDP port numbers
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 32
11.1.9 TCP and UDP port numbers
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 33
11.1.9 TCP and UDP port numbers
• Numbers below 1024 are considered well-known port numbers.
• Numbers above 1024 are dynamically assigned port numbers.
• Registered port numbers are those registered for vendor-specific applications.
• Most of these are above 1024.
1024 is 10 bits. There are 16 bits (65,536) available for port numbers.00000011 11111111
All zeros in the first six positions means it is a “well-known” port
number.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 34
11.1.9 TCP and UDP port numbers
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 35
OVERVIEW11.1 TCP/IP Transport Layer
11.1.1 Introduction to transport layer
11.1.2 Flow control
11.1.3 Session establishment, maintenance, and termination overview
11.1.4 Three-way handshake
11.1.5 Windowing
11.1.6 Acknowledgment
11.1.7 Transmission Control Protocol (TCP)
11.1.8 User Datagram Protocol (UDP)
11.1.9 TCP and UDP port numbers
11.2 The Application Layer11.2.1 Introduction to the TCP/IP application layer
11.2.2 DNS
11.2.3 FTP
11.2.4 HTTP
11.2.5 SMTP
11.2.6 SNMP
11.2.7 Telnet
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 36
Application Layer
eg. Dialog Control is • Session Layer in OSI• Application Layer in
TCP/IP
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 37
11.2.1 Introduction to the TCP/IP application layer
• Domain Name System (DNS)
• File Transfer Protocol (FTP)
• Hypertext Transfer Protocol (HTTP)
• Simple Mail Transfer Protocol (SMTP)
• Simple Network Management Protocol (SNMP)
• Telnet
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 38
11.2.2 DNS
eg. http://www.harvard.edu/
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 39
11.2.2 DNS
eg. Non-Profit organizations
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 40
11.2.2 DNS
.us USA
.ca Canada
.au Australia
.cl Chile
.de Germany
.hk Hong Kong
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 41
11.2.3 FTP and TFTP
• Both TFTP and FTP are used to transfer files between systems.
• TFTP is limited to Read, Write and Mail.
In Semester 2 we will use TFTP to load and retrieve ISO images from a router.
FTP uses TCP thence is
connection oriented.
TFTP uses UDP thence is NOT
connection oriented.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 42
11.2.4 HTTP
Eg. http://uno.slctech.org/~clark/ …the TCP protocol is http, the domain name is slctech.org, the machine is uno, and the folder is ~clark.
DNS is used to translate a web address into an IP address.
HTTP (not shown port 80) uses TCP thence is connection oriented.
DNS can use either TCP or
UDP.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 43
SMTP• offers very little
security • no authentication
11.2.5 SMTP
Email servers communicate with each
other using SMTP.
Clients collect their mail using POP3 or IMAP4.
SMTP uses TCP
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 44
11.2.6 SNMP
•Network Management System is the central point for SNMP.•It uses the majority of memory resources.
Managed devices:Eg. Routers,
switches, hosts etc.Agents report back to the NMS the status of the items in their MIBs
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 45
• Network management system (NMS)
• NMS executes applications that monitor and control managed devices. The bulk of the processing and memory resources required for network management are provided by NMS. One or more NMSs must exist on any managed network.
• Managed devices
• Managed devices are network nodes that contain an SNMP agent and that reside on a managed network. Managed devices collect and store management information and make this information available to NMSs using SNMP. Managed devices, sometimes called network elements, can be routers, access servers, switches, and bridges, hubs, computer hosts, or printers.
• Agents
• Agents are network-management software modules that reside in managed devices. An agent has local knowledge of management information and translates that information into a form compatible with SNMP.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 46
11.2.7 Telnet
Telnet uses TCP thence is connection
oriented.
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 47
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 48
OVERVIEW11.1 TCP/IP Transport Layer
11.1.1 Introduction to transport layer
11.1.2 Flow control
11.1.3 Session establishment, maintenance, and termination overview
11.1.4 Three-way handshake
11.1.5 Windowing
11.1.6 Acknowledgment
11.1.7 Transmission Control Protocol (TCP)
11.1.8 User Datagram Protocol (UDP)
11.1.9 TCP and UDP port numbers
11.2 The Application Layer11.2.1 Introduction to the TCP/IP application layer
11.2.2 DNS
11.2.3 FTP
11.2.4 HTTP
11.2.5 SMTP
11.2.6 SNMP
11.2.7 Telnet
Nov-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod11 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 49
FIN