Day 2

- Communication Servers
-
- Modems

Network media = Fiber, copper, wireless.
Copper, twisted pair: problem with copper electromagnetic interference.
Fiber, uses light pulses.
Wireless, electromagnetic waves for wireless.

Considerations:

1. How far you need to go.
2. Distance
3. What kind of bandwidth
4. Cost of installation, connectors, etc.
Types of networks:
1. LAN – a group of IN devices in control of a single administrator.
2. WAN – tend to connect geographically challenged locations.
3. Internetwork – collection of two more LAN’s.
4. Intranet – is a private web network that is closed to the public.
5. ISP
6. NIC – is a physical connection to the network. Network Internet Connection.
7. Port – physical port, where you can plug in a cable.
8. Protocols are rules.
Protocols define sharing, update message, starting/stopping communication.
IEEE - standardized the protocols that everyone agreed to.
IETF – Internet Engineering Task Force, the protocols they designed are provider independent.
A group of protocols can be grouped in a different Layer.
Protocol model, describes functions that occur.
Reference model, gives you a common reference for each layer.

TCP/IP suite PiPP:
- Application (httpd)
- Transport (communication between devices)
- Internet (path selection)
- Network (hardware and media)
OSI Model:
- Application layer. 7
- Presentation 6
- Session 5
- Transport 4
- Network 3
- Data Link 2
- Physical 1
Incapsulation: Take data and capsulate it as data goes as you go from layer 7 to layer 1.
Decapsulation: Data going from layer 1 to layer 7.

- Data Link, Layer 2 – FRAMES = Mac.addr
- Network, Layer 3 – Packets = IP ADDR
- Transport, Layer 4 = Port. Address

Chapter 3: Application Layer, first step on getting data off to the internet.

It has:
- Applications: software used to communicate over the internet. Not windows/excel/etc.
- Services: File transfer.
- Protocols: HTTP, FTP, DNS. Exchange data between source and destination.

APPLICATION LAYER (Layer 7) - first step on getting data off to the internet.

PRESENTATION LAYER (Layer 6) - coding and conversion of the application layer. Compression, encryption, etc.

SESSION LAYER (Layer 5) - establishes a session, mantains a session, and terminates a session.

Telnet, is an application, a service, a protocol. Telnet allows you to have remote access to another device

Client server model = a requesting device, "please send me some data"
Server model = is a responding device. Server can handle multiple clients at one time.

Daemon = service that is running on the background, it listens for a request and then respond.

PEER-TO-PEER = two or more computers connected to a network.

PORT NUMBERS::

-DNS can be TCP/UDP port 53.
-HTTP is TCP port 80
-SMTP is TCP port 25
-Telnet is TCP port 23
-DHCP

Day 1

1. protocols

identified sender and identified receiver

agree on method of communication

common language and grammar (Cisco IOS)

speed and timing

confirmation or aknowledgement (ACK) of data received


2. Network itself

Quality of the pathway.

Number of times the message changes for (from switch to switch, etc)

Number of times a message is redirected

Number of messages sent at the same time

Size or complexitity of the network

3. Elements of a network

a) Protocols (set of rules)
b) Messages (units of information)
c) Medium (whatever is being sent over, fiber, copper, etc)
d) Devices (routers, switches, hubs)

TCP - Transmission Control Prot.
TCP/IP - " " "

Services:

www = HTTP
email = SMTP/POP

9781587132032 = Lab book


Convergence -

Network architecture - Conceptual plans to build a network

a) Fault tolerant - alternative pathways

b) Escalability

c) Quality of Service (QoS) -

d) Prioritize traffic

e) Security (firewalls)

Security:

- Network infrastructure, security, physical plan.
- Content security, protecting the data on the devices themselves.
- Availability, data available when user needs the data.