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EUI-48
- IEEE forms mac addresses from a numbering system. used to be called mac-48
- 48 bits - 24 bits oem - 24 item #
- extended unique identifier
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what cmd prompt shows MAC
ipconfig /all
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generic Ethernet frame contains 5 boxes
to mac, from mac, type, data, fcs
- type is the type of data encap
- fcs uses a math called cyclic redundancy check - done by receiving MAC
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size of frame
and
is there larger
1500 bytes - this helps all nics get their data through the network at the same time
yes, jumbo frame
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MAC know other MACS How?
- table from earlier communications
- or
- send broadcast FF:FF:FF:FF:FF:FF which is the layer 2 broadcast address
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unicast frame
a frame that is addressed specifically to another device's MAC
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how does the switch handle unicast frames versus broadcast frames?
- uni is to the specific mac address
- broadcast is to all in the broadcast domain
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nics operate at two level
layer 2 data link as well as 1 for physical
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switch is layer?
2 -data link
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what are the two sub layers of the data link layer 2
LLC logical link control - uses device drivers to talk to the os
MAC - media access control -makes and addresses frames
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logical addressing
- requires special software called a network protocol. example is tcp/ip protocol suite
- ip addresses
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physical address
MAC address
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ip operates at what level
ip is layer 3 the network layer
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what container forms at layer 3
the ip packet
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what is a PDU
protocol data units
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dotted octet numbering system
- 192.168.4.232
- based on four 8-bit numbers
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what device connects two subnets
router
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router uses what form of addressing
logical
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how does a router process a frame
it strips off the frame checks the ip address in the ip packet and re-frames it and sends accordingly
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what is the frame call for a cable modem
docsis
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segmentation
dicing of data packets into segments or datagrams at layer 4 for transport. sequencing is also done here. datagrams are not sequenced
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reassembly
putting the diced chunks of data in order and verifying good
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session layer handles what
application to application
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command to see sessions running
netstat -a
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presentation layer
translates data from lower layers into a format usable by the application layer
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tcp model link layer is what 2 osi layers
physical and data link
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what happens at the internet layer of the tcp model
the internet layer -deals with the ip packet creation (made up of the osi network layer)
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what happens at the transport layer of the tcp model
is part osi transport, session and some app layer.
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IMAP
internet message access protocol. it is a tcp/ip protocol
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sample connection oriented
IMAP
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sample connectionless
VoIP
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how do you make a tcp segment
strip away the ip addresses from an ip packet
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what is in a tcp segment
- destination port
- source port
- sequence number
- check sum
- flags
- acknowledgement
- data
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what does it mean "tcp segment port"
tcp segment port is two port src and dest the first 1024 are "well known ports" like 80 for http
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how many tcp ports are there?
65536
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data is what layer of tcp model
application
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tcp layer that breaks data into tcp segment
transport layer
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tcp layer that creates ip packets
internet layer
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in tcp model what layer deals with frames
link layer
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what is UDP
it is a connectionless protocol and stands for User datagram protocol
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what fields exist in tcp segment
- dest port
- src port
- seq number
- checksum
- flags
- ack
- data
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what fields exist in a UDP datagram?
- dest port
- src port
- length
- checksum
- data
doesn't care if rec pc gets it
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what is topology
nothing more than the organization of how the ones and zeros in the form of frames move from host to host.
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Bus Topology
all connected by a single cable in the ceiling
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Ring Topology
consists of single ring of cable with no ends; IBM token ring
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Star Topology
Hosts are plugged into a block in the middle. Rare, very old. Star is a physical topology.
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Star - Bus Hybrid Topology
First have classic bus. Then, shrink bus into box. Looks like a star but is a bus in the box.
Physical versus Logical
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Mesh Topology
Each computer is connected directly to every other host (Fully Meshed). If not, Partially Meshed (wireless network). Best for radio waves.
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Coaxail cable layers
copper core conductor > white insulation> 2nd conductor > insulation
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OHMs
measure of resistance
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RG-58
- 50 OHM
- BNC connector; twist lock not threaded
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RG-59
- 75 OHM (TV)
- F-type connector
- FC
- Threaded for cable
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twisted pair cabling
- twisted allows signal to move further down the wire
- can have many strands most common is 4 pairs
- watch out for interference
- cheap
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What are the two cabling standards
EIA 568A and EIA 568B
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name the color order of EIA 568A
- 8 brown
- 7 brown white
- 6 orange
- 5 Blue white
- 4 Blue
- 3 Orange white
- 2 green
- 1 green white
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Name the color order of EIA 568B
- brown
- brown white
- green
- blue white
- blue
- green white
- orange
- orange white
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Cat 1
telephone systems not networks
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CAT 6 and CAT 6a
- different number of twists per inch
- different types of plastic controllers
- kvlar
- 1 gbps 100 meters - cat 6
- 10 gbps 100 meters - cat 6a
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cat 7
- usually shielded
- 10 gbps 100 meters
- not really a standard yet eclipsed by 6a
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cat 3
- 10 mb per second
- 100 meters
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cat 5
cat 5e fixes some issues with 5
- 100 mbit per second
- 100 meters
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what do wire category ratings define?
- speed and length
- number of twists per inch
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what colors are fiber optic cables
yellow and orange
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Name the parts of a fiber cable
- glass core
- cladding - light reflects off of this
- cable jacket
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What are the two types of fiber optic cabling
- single mode - yellow - designed to be used with lazers, thinner fiber goes loooong distance and has 2 connectors
- multimode - orange - designed to propagate lights - always has two connectors (LED)
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ST connector
fiber connector that punches in and twists
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SC connector
are square just push in
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LC Connector
two connectors built into one
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MT-RJ Connector
Two connectors
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physical contact fiber
PC with slightly rounded edges
less desired
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ultra physical contact
- upc
- more rounded
- less light loss
- more desired
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angle physical contact
- APC
- 7 degree angle
- more desired
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What is the Plenum-rated fire rating
- Plenum-rated - is a space between the dropped ceiling and the actual ceiling
- or
- the space between a raised floor and the actual floor
Highest fire rating and resistance
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What is the Riser-rated fire rating
designed to run between floors in a building
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What is the PVC or non-plenum fire rating
no fire protection at all
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two old network connections
- serial ports - oldest -rs-232 language - db-9 and db-25
- parallel ports - iEEE 1284 - db 25 female for printers and lantastic
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IEEE 802.3
Ethernet standard
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What is a rollover or yost cable?
Used on high end routers to interface with the device using a serial connection and db-9 serial port
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Basic Ethernet Frame parts
- Preamble - I am coming
- Destination MAC -
- Source MAC -
- Data Type - Ether Type - 2 bytes/octets what data type are we hauling i.e. ARP, IPV4, etc.
- Data - Minimum must be 64 bytes will pad if under. Max is 1522 octets
- (PAD) -
- FCS - Frame Check Sequence - 32 bytes
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Jumbo Frame size on high speed network
MTU max. transmission unit
9000 bytes
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define
10BASE5
10mb baseband 500 meters
used BNC connector on cable; pc had t-connector into mac card
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CSMA/CD - segmented cable only
- Carrier Sense Multiple Access
- Collision Detection
frame goes both directions; need terminator resistor to prevent reflection
computers can't talk at same time
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10Base2 define
10 mbits baseband 200 meters
used BNC connector on cable; pc had t-connector into mac card
up to 30 devices
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define 10BASET
10 mb baseband max 100 meters
CAT 3 or better
no more than 1024 nodes
old slow ; bus in a box
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how to crimp straight through cables
- plastic piece is a crimp
- crimper
- 1) cut jacket
- 2) untwist wires and put in order
- 3) Use collar to prealign
- 4) Slide into crimp
- 5) With Tab up, green on left from behind crimp; hold up and make sure each goes up
- 6) Crimp it
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EIA/TIA 568A
- 1-8
- 1)green/white
- 2)green
- 3)orange/white
- 4)blue
- 5)blue/white
- 6)orange
- 7)brown/white
- 8)brown
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how is a crossover cable different
2 transmit and 2 receive
one is 568A and 568B on the other end
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what is the technical term for an RJ-45 connector?
8P8C connector
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things to know about csma/cd
- bandwidth is split by number of conversations
- mac cards roll the dice of milliseconds
- collisions are common
- collision domain - can hear same collision plugged into same domain
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switch communication
- builds a mac address table to port
- it will update in milliseconds
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What is the broadcast mac address
FF:FF:FF:FF:FF:FF
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reasons to broadcast?
announce network name, trying to find specific computer
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what is a broadcast domain
hooked to a switch and can hear others broadcasts
maintenance ports allow to hear others traffic like hub
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What layer is frame, packet, segment
layer 2, 3, 4
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is a hub a repeater
yes it sends a copy of frame to all other connections
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what information do i get with ipconfig?
ipv, subnet mask, gateway
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how many character is mac address
48 bits, 12 char
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what is a broadcast frame?
FF-FF-FF-FF-FF-FF every device processes
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what is a broadcast domain
all computers that can hear the broadcast basically all plugged to hub/switch
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Example of logical addressing?
IP addressing
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if a frame is for a pc on another network id, what mac addresses is used.
the destination mac address is that of the default gateway router, the destination ip address is for the intended pc. At the router, the frame (mac address) is stripped off leaving ip addresses. Then the router reattaches new mac addresses, the dest is the receiving pc mac address and the src is the router's mac address.
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how many well known ports?
0-1024
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how many not well known ports?
1025-65535
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