Most of this is going to be a review of my notes from the Network Fundamentals class. Over time, I may add links to videos on subnetting as well.
Segments of Original Notes
More after the break
Review
From CSIT 1730
Network
Models
·
OSI -> Know the 7 layers – Please Do
Not Throw Sausage Pizza Away
o
7 Application- user interaction
layer. This is what we see.
o
6 Presentation- this is where the
computer translates the information to what the application will show us.
o
5 Session- Establish and ends the
connection.
o
4 Transport- the layer that breaks down
the information that will be sent into manageable segments and how
communication will be set up.
§ 2mg
email broken down into 2 segments of
1mg each.
§ Flow control-
making sure that both devices are able to communicate by making sure they can
communicate at all times. Window size is deciding how many
segments to send before waiting for an acknowledgment.
o
3 Network- Routing and IP
addressing. This layer decides how to
send the segments to the address it is heading to. Also packets the data to send it to layer 2.
o
2 Data Link - Frames your data to
protect it.
§ Sublayers
·
LLC- logical link control- the control
that talks between the physical device and the data link layer
o
Makes sure that layers 2 & 3 are
ready to talk to each other and they understand each other.
o
Detects errors.
·
MAC- machine access control- physical
item
o
1 Physical- translates to binary
data. Handles physical media standards.
§ Sends
and receives the bits.
·
The DoD model / TCP/IP
o
Department of defense, US standard
o
4 layers
§ Application
·
OSI- Application, Presentation and
session layers
§ Host
to host
·
OSI- Transport
§ Internet
·
OSI- Network
§ Network
access
·
OSI- Data link and Physical Layers
·
Each layer is dealt with in different
ways. It also makes troubleshooting
easier. Makes it much easier to develop
on the layers. It also makes it possible
for specialization.
·
Models are for standardization.
Types
of Cables
·
Cable Standards- TIA/EIA A/B
o
UTP Cables- Unshielded Twisted Pair
(Twisted Pair) (Copper)
o
We twist the copper wires to keep
interference down. The more twists, the
better the signal quality.
§ Straight
through
·
1,2,3,6
Do not use 4,5,7
o
1------1
o
2------2
o
3------3
o
6------6
·
When to use?
o
Connecting a PC to a hub/switch
(different devices)
§ Cross
Over
·
1,3 & 2,6
o
1----3
o
2----6
o
3----1
o
6----2
·
When to use?
o
Connecting two computers (like devices)
§ Rollover
(Flip em!)
·
Uses all 8 pins
o
1----8
o
2----7
o
3----6
o
4----5
o
5----4
o
6----3
o
7----2
o
8----1
·
Used?
o
Mostly used for console
connections. Used to configure devices
and change settings.
·
Source
o
UTP Electricity
o
Fiber- Light- Laser or LED
·
Distance
o
UTP 100m/328ft
o
Fiber Single Mode-25 miles/40km Multi
Mode- 3000ft/1km
·
Disadvantages
o
Twisted Pair is unsecure- easy to add
points to listen in. There is more
interference due to signal type.
Distance is also a factor- long distances require a signal booster.
o
Fiber is really expensive and not very
flexible. Installation can only be done
by someone licensed.
·
Advantages
o
Fiber- Speed, distance, Secure, no
interference
o
Twisted Pair- cheaper
Network
Design Requirements
o
How many subnets do I need?
o
How many devices do I have to support in
those subnets?
o
Must leave 2 bits to the host id- one
for the addressing and one for broadcasting
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