User:Itpastorn/dko/ccna1-3.1-11

TCP/IP Transport and Application Layers

Overview CCNA 1 - Module 11 (3.1)
 * The functions of the transport layer
 * Flow control
 * How a connection is established between peer systems
 * Windowing
 * Acknowledgment
 * Transport layer protocols
 * TCP and UDP header formats
 * TCP and UDP port numbers
 * The major protocols of the TCP/IP application layer
 * Features and operation of well-known TCP/IP applications

Introduction to the TCP/IP transport layer

 * Segmentation
 * End-to-end operations
 * Flow control, sliding windows
 * Sequence numbers, acknowledgements

Connection establishment, maintenance, and termination

 * Congestation
 * Three way handshake - connection parameters
 * "Buffer full", "not ready" --&gt; Process segements --&gt; "Ready"

Windowing
The quantity of data that a machine can transmit on the network without receiving an acknowledgement
 * The ACK number refers to the next packet that is expected

TCP

 * The segment
 * Used by
 * FTP
 * HTTP
 * SMTP
 * Telnet and SSH

UDP

 * The segment
 * No windows
 * No ACKs
 * Used by
 * TFTP
 * SNMP
 * DHCP
 * DNS
 * NFS (normally, TCP is better over long distances)

TCP and UDP port numbers
Ports, IANA
 * 20,21 - FTP
 * 22   - SSH
 * 23   - Telnet
 * 25   - SMTP
 * 53   - DNS
 * 69   - TFTP
 * 80   - HTTP
 * 123  - NTP
 * 137,139 - NetBIOS (Windows needs them!)
 * 143  - IMAP
 * 161  - SNMP
 * 179  - BGP
 * 194  - IRC
 * 443  - HTTPS
 * 520  - RIP
 * Well-known ports (0-1023)
 * Registered ports
 * Dynamically assigned ports
 * Reserved ports

The three way handshake

 * 1) SYN ( seq = x ); INS = Initial Sequence Number
 * 2) SYN ( seq = y ) + ACK ( x +1 ); Received x, expecting x + 1
 * 3) ACK ( y + 1)

Introduction to the TCP/IP application layer
(Repetition)

DNS

 * TLD = Top Level Domain
 * com
 * edu
 * net
 * org
 * Int
 * gov (USA only)
 * mil (USA only)
 * us
 * se
 * nu
 * to
 * museum
 * aero
 * biz
 * Types of records
 * A
 * AAAA
 * MX
 * CNAME
 * Types of servers
 * Caching Name Server
 * Top Name Server
 * Authoritative Name Server
 * LAN server
 * Tools
 * dig
 * nslookup
 * whois
 * whois

FTP and TFTP
TFTP is used by PXE and Cisco routers to download IOS images and configuration files.

HTTP
Anatomy of the URI Common commands Virtual hosting
 * protocol
 * user
 * password
 * hostname
 * domain
 * path
 * resource
 * get variables
 * fragment
 * GET
 * POST
 * HEAD
 * PUT

SMTP
(POP3,IMAP4)

SNMP
Alternative: RMON
 * Network management system (NMS)
 * Managed devices
 * Agents

Telnet

 * A service
 * A protocol
 * A command (that can connect to any port)
 * Telnet sends everything, including passwords, unencrypted. Use SSH!

Extra topics (in addition to CCNA)

 * Datagram Congestion Control Protocol (DCCP)
 * Stream Control Transmission Protocol (SCTP)
 * Virtual circuits

Additional resorces (besides Wikipedia)

 * How the Transport Layer Works at Learn Networking
 * How the Application Layer Works at Learn Networking

Navigation

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