Networking

1
Networking

• the good, the bad the ugly.

2
The OSI 7 layer model

• Application
• Presentation
• Session
• Transport
• Network
• Data-Link
• Physical

3
Physical Layer

• Type of cable (or radio wave).
• Bit-by-bit transmissions.

4
Data-Link Layer

• Frame-by-frame discussion.
• Verifies receipt.

5
Network Layer

• Addressing the data.
• Name to number conversion.

6
Transport Layer

• Breaks data up into chunks.
• Verifies transmission and receipt.

7
All the Other Layers

• Session - controls how transport will happen.
• Presentation - encryption, compression, etc.
• Application - www, e-mail, etc.

8
3 Must-Have Things( 1 more too.)

• IP number. - x.x.x.x where 0x255
• Subnet Mask. - 255.255.255.0
• Gateway. - x.x.x.x, usually x.x.x.1
• and a DNS server.

9
MAC address

• Every machine on a network must have one.
• It must be unique.
• 48 bits long - 281 trillion machines.
• Gets converted to IP number by gateway.

10
Hardware

• Cards or NICs
• Hubs
• Switches
• Routers
• Firewalls

11
NICs

• MAC address.
• Interface Type
• Connectors

12
Hubs

• The Gossips of Networking
• Cheap. Cheap. Cheap.

13
Switches

• Switchboard Operators
• Memorize IP and MAC address
• Cheap. Fast.

14
Routers

• The Dumb Gatekeeper.
• Slow(er).
• Not as Cheap.

15
Firewalls

• The Smart Gatekeeper.
• Slow(est).
• All Prices.