ESSENTIALS OF NETWORKING
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Ethernet was invented in networking to fix bandwidth hogging
Internet data travels in 1500byte ethernet "frames"
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MAC address *for every computer on a Network
(MAC address = media access control address)
MAC address (sometimes called PHYSICAL ADDRESS)
is 12 hexadecimal digits # broken up by : Looks like long lottery number w/dashes
4C : 7C : 5F : 0B : 54 : 05
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12 hexadecimal digits - First 6 digits are called "OEM ID"
4C : 7C : 5F : 0B : 54 : 05
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Curious about what your MAC-address is Windows??
Open command screen- COMMAND ipconfig /all
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a DATA TRAIN
or 1500byte "ETHERNET FRAME" - always contains these:
Destination MAC-ADDRESS + source MAC-ADDRESS + DATA + FCS (frame check sequence)
(we include source MAC-ADDRESS incase receiving PC wants to talk back)
FCS "frame check sequence" makes sure the data is in proper order
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an IP address is only important for WIDE AREA NETWORKS "WAN"
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Difference between HUB and SWITCH??
HUB
"repeater" makes actual copies of data
& blasts it back out to everyone on network.
Everyone else's macAdress just ignores the duplicated data if was not meant for them
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SWITCH
"smart repeater" SWITCH remembers the macAddress of all PCs
Then just rifles data to intended destinations (makes no copies)
SWITCH is way faster.. don't have everyone talking over each other
the "copying" HUB uses up limited bandwidth
**SWITCH learns macAddresses of everyone connected**
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All addresses are divisible by 4
Letters never go beyond F
**based on a Hexadecimal 16 digit numbering system**
Base 16 counting & only 16 combinations
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0000 = O
0001 = 1
0010 = 2
0011 = 3
0100 = 4
0101 = 5
0110 = 6
0111 = 7
1000 = 8
1001 = 9
1010 = A
1011 = B
1100 = C
1101 = D
1110 = E
1111 = F
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This 16digit data code helps shorten the Binary DOS of ZEROS and ONES
MAC address is 12 hexadecimal digits # broken up by :
12x4 = 48
a 48bit cluster of data that PCs decode
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LAN can only handle about 30 to 40 office computers
then a ROUTER connects those LANs to the wider internet
(like a magic box with tiny traffic cop inside)
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ROUTERs speak LOGICAL ADDRESSING aka "IP address"
first 7 digits (IP address) are the same on all devices on a LAN
*but after that individual devices have unique numbers (IP and MACaddress)*
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CABLES for networking:
ETHERNET
10base T = 10mbps Baseband twisted pair
100base T
1000base T
10GBbase T (that's as high as they go)
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DOCSIS (cable modems)
COPPER vs FIBER OPTIC
OLD-ass Coaxial. Comes in 3 ratings.
RG-58 (super thin BNC connector)
RG-59
RG-6 (F type connectors. Threaded screw on end)
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CAT RATINGS for CABLES
PLENUM RATINGS (based on CABLES ability to resist fire):
1. PVC general purpose non-plenum = Cheap but dangerous to put in areas that get hot
(crawlspace, attic, kitchen, under house)
2. Riser = less vulnerable than PVC. (used to go through floors)
3. PLENUM = resistant to fire
**always read building codes**
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UTP unshielded Twisted pair
& "strands" like hair inside = Best for plugging into PATCH PANEL
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version1 - RJ-11 looks like telephone cable
version2 - RJ-45 w/8 contacts
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STP: shielded twisted pair. Super strong.
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Fiber Optic Cables
**Uses light - not electricity**
(Looks like hair made of kevlar. FIBER GLASS)
SINGLEMODE fiber = uses actual lasers
Fiber optic cable tends to come in 2 wires (1 sends info - 1 receives)
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CUTTING + CRIMPING
(if you need to build or fix a cable)
Crimps are the little plastic teeth at end of ethernet
make sure crimp tooth is compatible with wire
CABLE CRIMPER & CUTTER looks like bolt cutter scissors
Inside Cable is different 4 coloured wires = TIA 568A / TIA 568B
*each with 8 pins on the crimp
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Untangle wires then lay them flat *like "zebra fruit" strips of gum
Push wires into the "tooth". Then use crimper to smoosh it together.
Check for
1. continuity - cables connected at both ends
2. Wire map. Are the coloured wires lined up properly? ("straight through cable")
FLUKE NETWORKS TESTER will show 2 identical sets of numbers if you did cabling right
CROSSOVER CABLE is when you accidentally flip colors one side of cable
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8 pins on ethernet cable - RIGHT TO LEFT
(but from above looks like left to right)
T568A goes
Green stripe < green < stripe yellow < Blue < stripe blue < Yellow < stripe brown < brown
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T568B goes
stripe Yellow < yellow < stripe green < blue < stripe blue < green < stripe Brown < brown
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When STRUCTURED CABLING
a) Start at MDF "main distribution frame" closet/room:
Equipment racks, at "U" height (file cabinet size), PATCH PANELs,
hubs + switch, server computers, wires, etc.
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b) HORIZONTAL RUN (T.I.A. RUN):
PC < WALL OUTLET < RISER < PATCH PANEL + new ethernet < switch
T.I.A. rules states: HORIZONTAL RUN can be maximum 90meters
(295.276 feet, 98 yards) basically a football field
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Back of PATCH PANEL has a bunch of plastic groove teeth
with TIA 568A and TIA 568B sides
Use 110 punchdown tool to "punch" wires down into the grooves
FLUKE NETWORKS TESTER comes with adapter for PATCH PANEL
**and remote part for WALL OUTLET**
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When FLUKE NETWORK TESTING a HORIZONTAL RUN
do "continuity test" + "wire map test"
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you can also Test locate the HORIZONTAL RUN with
a Fox & the Hound (tone generator & tone probe)
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TDR "time domain reflectometer"
= tells you the length of cable via speed of light
(If TDR reads out shorter length than what you measured- there's a broken cable somewhere)
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