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uNit 4 – Network
Computing Systems
1
Index
► Introduction
► Types of networks
► Classification
► OSI Model
► TCP/IP vs OSI
► Network Acces
► IEEE Standards
► Transmission media
► Transmission techniques
► Disturbances
► Services and Functions
► Internet
► IPv4
► ARP
► Netplan
► Routing
2
Network systems
► Transport
► Function, Services and Primitives
► Public and Private keys
► SSH
► Application
► SCP and RCP
► LZW
► DNS
► DHCP
Introduction
► Data
► Computers, Printers, scanner, to sum up devices.
3
The target is Share resources!
► Between peers or through the world.
► Reliably and Safely.
The challenge is connect devices.
Client Server
Network
JavaScript
PHP
History
4
Font:https://www.microsiervos.com/
Font:https://www.eurokonzern.es/
Font:https://es.wi
kipedia.org/
Font:http://iner1.blogspot.com/
X.21
Font:https://networking.ringofsat
urn.com/Protocols/X21.php
Font:https://slideplayer.com/slide/3207708/
A sum up
► Telegraph
► Telephone
► Modem
► Arpanet
► IBM SNA
► X.21 and X.25
► OSI Model
► TCP/IP
TCP/IP
OSI MODEL
I. Bit transmission system
II. Keep link without error
III. Routing and congestion control
IV. Connection peer to peer
V. Improvement services peer to peer
and reconnection without error
VI. Compressing data, encryption,
manage syntax and semantic
VII. Allow user protocols and processes
5
Open System Interconnection treat separately:
OSI basic reference model described in ISO 7498-1 (1984)
Application
Presentation
Session
Transport
Network
Data Link
Physical
Application
Presentation
Session
Transport
Network
Data Link
Physical
Network
Data Link
Physical
Network
Data Link
Physical
Protocols Data unit (PDU) N to N
Services
N
to
N+1
“Divide and Conquer.”
Font:https://community.fs.com/
TCP/IP vs OSI
APPLICATION
TRANSPORT
INTERNET
NETWORK ACCES
Type of networks
► Body area network BAN
► Personal area network PAN
► Local area network LAN
► Campus area network CAN
► Metropolitan area network MAN
► Wide area network WAN
7
According to size:
Classification
► Server-Client
► Peer-to-Peer
According to services:
BAN
PAN
LAN
CAN
MAN
WAN
8
► BUS
► STAR
► RING
► MESH
► TREE
According to topology:
Font:https://www.assignmenthelp.net/assignment_help/network-topology-and-types
9
Network Acces
► Type of signals
► Electrical parameters
Physical interconnection
Physical and Data Link OSI Model
► Communication protocols
► Detection and error correction
► Compatibility
Logical specification
Telematics
Remote
communication
techniques
Communications
► Simplex
► Duplex
► SemiDuplex
Transmitter Channel Receiver
Disturbances
Signals
► Sincronus / Asincronus
► Digital / Analog
► Baseband / Modulated
► Serial / Paralel
802.6
Optical
FIber
802.15
Bluetooth
MEDIA
ACCES
CONTROL
10
IEEE STANDARDS
802.1
Management
802
General
view
802.3
CSMA/CD
Ethernet
802.4
Token
Bus
802.5
Token
Ring
802.11 WLAN
802.11
IR
802.11
FHSS
.11a
OFDM
.11b
DSS
.11g
DSS
OFDM
802.2 Logical Link Control LLC
LLC
Data Link
PDU: Frame
Physical
PDU: Bit
802.16
Wimax
SONET
SDH
RS-232
(Recommended Standard 232)
DTE
Data terminal Equipment
DCE
Data Circuitering Equipment
DB25
DB25
Modem
Telephone Network
Physical example protocol
► Modulation
► Synchronisation
► Init and end
► Multiplexing
► Carrier Detection
► Filtering and Equalization
Services:
► Peer to Peer / Multicast
► Duplex/Semi Duplex/Simplex
► Electronics /Optical/Mechanical
► Topology
► Serial / Paralel
Functions:
► Guided
► Twisted pair (Unshielded UTP or Shielded STP)
► Coaxial 50Ω or 75Ω
► Optical Fiber
► Not guided
► Microwave
► Infrared
► Others (LIFI, HF etc)
11
Transmission media P1
P3
P4
P2
1 2 3 4 5 6 7 8
RJ-45
Font:https://www.pinterest.es
Cat 5 100Mbps Carry 100MHz
Cat 5e 1Gbps Carry 100MHz
Cat 7 10Gbps Carry 600MHz +Shield
Cat 8 25Gbps Carry 2000MHz
Cat 6 1Gbps Carry 250MHz +Performance
Font:https://miracomosehace.com/
12
Font:https://es.wikihow.com/crimpar-una-clavija-RJ-45 and
https://www.helicateringservices.com
► Guided
► Twisted pair (Unshielded UTP or Shielded STP)
► Coaxial 50Ω or 75Ω(TV)
► Optical Fiber
► Not guided
► Microwave
► Infrared
► Others (LIFI, HF etc)
13
Transmission media
Font:https://miracomosehace.com/
COAXIAL Bandwidth 500MHz
10-Base 5 RG-8,RG-9,RG-11 10Mbps 500m
10-Base 2 RG-58A/U 10Mbps 200m
Bell Labs wave machine
► Guided
► Twisted pair (Unshielded UTP or Shielded STP)
► Coaxial 50Ω or 75Ω(TV)
► Optical Fiber
► Multimode
► Monomode
► Not guided
► Microwave
► Infrared
► Others (LIFI, HF etc)
14
Transmission media
Snell’s law
Coating
Core
(n1)
Cladding
(n2)
If
All signal are reflected
Font:https://www.profesionalreview.com/redes/
► Guided
► Twisted pair (Unshielded UTP or Shielded STP)
► Coaxial 50Ω or 75Ω(TV)
► Optical Fiber
► Not guided
► Microwave
► Right of way allowed
► Poor performance with obstacles
► Authorization required
► Infrared
► Others (LIFI, HF etc)
15
Transmission media
Font:https://www.forbes.com/
>1GHz travel straight
Font:https://mandoadistanciaparatv.com/
► Guided
► Twisted pair (Unshielded UTP or Shielded STP)
► Coaxial 50Ω or 75Ω(TV)
► Optical Fiber
► Not guided
► Microwave
► Infrared
► Others (LIFI, HF, etc)
16
Transmission media
Font:https://movitherm.com/knowledgebase/thermal-infrared-imaging-explained/
Font:https://support.polar.com/
17
► Base Band
► Modulated Band
► Digital Modulations
► Multiple access
Transmission techniques
18
► Base Band
► Modulated Band
► Digital Modulations
► Multiple access
Transmission techniques
19
► Base Band
► Modulated Band
► Digital Modulations
► Multiple access
Transmission techniques
People from other class who don't known Complex numbers
20
► Base Band
► Modulated Band
► Digital Modulations
► Multiple access
► Time Division Multiple Access TDMA
► Frequency Division Multiple Access
► Code Division Multiple Acces
► TDMA/FDMA
► Spread Spectrum Multiple Access SSMA
► Direct Sequence Spread Spectrum DSSS
► Frequency Hopping FHSS
Transmission techniques
21
► Atenuattion
► Distortion phase or frequency
► Noise
► Thermal (Electronics components)
► Intermodulation (Other frequencies)
► Crosstalk
► Impulsive (Spikes)
► Echoes(multipath)
Disturbances
C = 2B log2 M
Where
C = Capacity of the channel
B = Bandwidth
M = Number of discrete signal or voltage level
S = Signal
N = Noise
C = B log2(1+S/N) bps
Nyquist f>=2B Shannon
Font:https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem
A (dB) = 10 log10 (PotT/PotR)
Where
A = Attenuation
PotT = Power Transmitted
PotR = Power Received
AΠ(t/T)
T
t
Echo
1/T , 2/T , 3/T ...
ATsinc(fT)
f
x0·Π(t/T)
x1·Π(t/T)· e^(j2Πt1/T)
...
xn·Π(t/T) · e^(j2ΠtN/T)
802.6
Optical
FIber
802.15
Bluetooth
MEDIA
ACCES
CONTROL
22
IEEE STANDARDS
802.1
Management
802
General
view
802.3
CSMA/CD
Ethernet
802.4
Token
Bus
802.5
Token
Ring
802.11 WLAN
802.11
IR
802.11
FHSS
.11a
OFDM
.11b
DSS
.11g
DSS
OFDM
802.2 Logical Link Control LLC
LLC
Data Link
PDU: Frame
Physical
PDU: Bit
802.16
Wimax
SONET
SDH
► Framework
► Error control
► Connection Oriented
► Flow control
► Offline services
► Not Flow control
Services:
► Error detection and correction
► Fragmentation and defragmentation
► Media access control
Functions:
Paritty
Generator
(k bits)
n bits n+k bits
Transmission
Splitter
Paritty
Generator
(k’’ bits)
k’’ bits
k’’==k’
k’ bits
n’ bits
No, Error!
Yes
Receiver
m
clk
c1
c0
00
10
01
11
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
0/00
1/11
c= 00 00 11 10 10
00 01 01 10 10
m=00110
r= 00 01 01 10 10
r= c+Error
Redundancy generator
Reception with error
Path with less cost (Hamming distance) give us the correct code
0
2
1
1
R1 R0
if m=1 c=11 then 1/11
Viterbi Algorithm
Hamming distance
00 11 2
01 11 1
11 01 1
00
10
01
11
0
1 1
0
0
1
1
2
0/01
1/10
R0
R1
4
0/00 0/00 1/ 1/ 0/
Generator
1
24
► Connection Oriented
► Establishing the link connection
► Data transmission
► Termination of the link connection
► Ensures reliable delivery of frames
► Transmission errors are detected
and bad frames are discarded
► All lost or erroneous frames are
retransmitted
► All duplicate frames are detected
and discarded
► Frames are delivered to the top layer
neat and error free
► The flow control is performed
between the emitter and the receiver
► To carry out error handling:
► Error detection techniques
► Frame numbering
► Confirmation of all frames received
correctly
► Retransmission unconfirmed frames
HDLC (High-level Data Link Control):
► Use
► Cisco devices
► Networks with high error
rates.
01111110
25
► Offline services
Not guarantee reliable delivery of
frames
► Transmission errors are detected
and bad frames are discarded
► Missing or erroneous frames are
not retransmitted
► Correct frames are not confirmed
► Possible duplicate frames are not
detected or discarded
► Frames are delivered to the top
layer in the order they arrive
► No flow control between emitter
and receiver
No establishment or connection end
phases
► Each frame is considered
independent of the rest
► Use
► Networks with low error rates (these
are the most common today)
► ADSL (PPPoE = PPP over Ethernet,
PPPoA = PPP over ATM)
PPP (Point to point) and LLC (Logic Link Control) protocol:
MAC Address
26
► MAC-48 deprecated
► EUI-48 2^48 (281.474.976.710.656)
► EUI-64 add 16 bits more (RFC 2464)
Media Access Control Address (MAC Address)
27
Internet
Network OSI Model PDU:Packet or Datagram
► All components has IP address
► Identify Network and Host
Addressing
► All component is routed to
destination using tables and
rules.
Routing
► IPv4 RFC791
► IPV6
IP addressing Classless Inter-Domain Routing (CIDR)
28
► 32 to be grouped in eights
► RFC5735 Classes and reserved addresses
► A mask is used to known Network or Host bits
► Some are Private IPs RFC1918:
► Class A
► 10.0.0.0 to 10.255.255.255
► Class B
► 172.16.0.0 to 172.31.255.255
► Class C
► 192.168.0.0 to 192.168.255.255
► Loopback RFC1122:
► 127.0.0.0 to 127.255.255.255
► Link-Local RFC3927:
► 169.254.1.0 to 169.254.254.255
► Multicast RFC1122:
► 224.0.0.0 to 224.0.0.15
► Future RFC1122:
► 240.0.0.0 to 240.0.0.15
► Broadcast RFC919:
► 255.255.255.255/32
IPv4
► Class A
► 0.0.0.0 to 127.255.255.255 Mask 255.0.0.0
► Class B
► 128.0.0.0 to 191.255.255.255 Mask 255.255.0.0
► Class C
► 192.0.0.0 to 223.255.255.255 Mask 255.255.255.0
► Class D
► 224.0.0.0 to 239.255.255.255
► Class E
► 240.0.0.0 to 255.255.255.255
29
Classe Extended mask Reduced mask Binary mask Wildmask
A 255.0.0.0 /8 11111111.00000000.00000000.00000000 0.255.255.255
B 255.255.0.0 /16 11111111.11111111.00000000.00000000 0.0.255.255
C 255.255.255.0 /24 11111111.11111111.11111111.00000000 0.0.0.255
Net Address Mask First Host Address Last Host Address Broadcast Address Nº Hosts
147.23.0.0 255.255.0.0 147.23.0.1 147.23.255.254 147.23.255.255 2^16 – 2 = 65534
30
192.168.1.109/2
4
192.168.1.1/24
Wireshark
IPv4 Datagram
ping 192.168.1.1
31
Address Resolution Protocol (ARP) RFC 826 and RFC 5227 / 5494.
I’m ready to sent to print for first time!. -The printer’s IP = 192.168.0.29 -
► Host: Hey there (sending to FF:FF:FF:FF:FF:FF) Who has ? 192.168.0.29
► Printer: to host...Hey! 192.168.0.29 is at 14:2d:27:bc:46:4d
Ok noted! Now I can send data to print to 14:2d:27:bc:46:4d
32
► systemctl stop network-manager
► systemctl start network-manager
► systemctl disable network-manager
► systemctl enable network-manager
► systemctl mask network-manager
► systemctl unmask network-manager
NetworkManager
33
Network Manager has nmcli to management
$ nmcli con add con-name eth1 type wifi ifname eth1 ipv4.method auto
$ nmcli con mod eth1 ipv6.method ignore
$ nmcli con edit
$ nmcli con reload
# nmcli radio
# nmcli device wifi rescan
# nmcli device wifi list
# nmcli device wifi connect SSID-Name
password wireless-password
34
Dijkstra algorithm for dynamic routing
STEP NODES
A B C D
0 0 inf/- inf/C inf/-
1 - 7/A 3/A inf/-
2 - 5/C - 11/C
3 - - - 7/B
A C
B D
3
7 2
2
8
35
Transport
Transport OSI Model PDU:Segment or Datagram
► Fragmentation / Defragmentation
► Multiplexing / Demultiplexing
► Flow Control
► Error Control
Functions
► Connection Oriented (TCP)
► Establishment
► Transferring
► Release connection
► Connectionless Communication (UDP)
Services
► LISTEN
► CONNECT
► SEND
► RECEIVE
► DISCONNECT
Host A Host B
time
Host A Host B
time
Primitives
36
► Provides a secure channel over an
unsecured network
► Use public and private key i useful
to scripting
SSH (Secure Shell)
type $env:USERPROFILE.sshid_rsa.pub | ssh pi@IP_ADDRESS "cat >> .ssh/authorized_keys"
ssh -X <user_name>@<ip_addres> -p <port>
Get-Service sshd
Start-Service sshd
Stop-Service sshd
cssh netadmin@192.168.1.{1..254}
$ sudo systemctl start ssh
$ sudo nano /etc/ssh/sshd_config
$ sudo systemctl reload ssh
scp .ssh/id_rsa.pub teacher@IP_ADDRESS:"C:ProgramDatasshadministrators_authorized_keys"
37
Application
Session OSI Model PDU: Transaction or Datagram
► Access point to services
► Establishment
► Release connection
Functions
► SCP Secure copy
► Authentication less (SSH do it)
► Encrypted data
► RCP Remote copy files
► rcp [-r] source-file|directory target-file|directory
Services
38
Application
Presentation OSI Model PDU: Datagram
► Data format
► Encryption
► Compression
► MP3, JPEG, AVI, Lemple-Ziv-
Welch(LZW)
Functions
39
TOBEORNOTTOBEORTOBEORNOT #
LZW
# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
TEXT CODE
T 20
O 15
B 2
E 5
O 15
R 18
N 14
O 15
T 20
TO 28
BE 30
TEXT CODE
TO 28
OB 29
BE 30
E0 31
OR 32
RN 33
NO 34
OT 35
TT 36
TOB 37
BEO 38
ORT 39
TOBE 40
RNO 42
OT # 43
TEXT CODE
OR 32
TOB 37
EO 31
RN 33
OT 35
# 0
40/15/33/35/37/41/37/41/33/43 there are 10 codes Log2(43)≈5,426 thus 60 bits
Alphabet has 27 letters Log2(27)≈ 4,75 thus 135 bits
Arround 50%
Compression !!
40
Application
Application OSI Model PDU: Datagram
► Applications and interfaces
► Show human readable
► Telnet, FTP, DNS, SMTP
Functions
Dynamic Host Configuration Protocol
(DHCP)
Under UDP
Client sent DHCP Discovery to broadcast and port 67, from IP 0.0.0.0 and port 68
Server sent DHCP Offer to broadcast
IP: source=192.168.1.1; destination=255.255.255.255
UDP: source port=67; destination port=68
sudo dhclient -r
41
To finish....
42
Thanks!

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Unidad 4 – Redes de ordenadores (en inglés).pptx

  • 1. uNit 4 – Network Computing Systems 1
  • 2. Index ► Introduction ► Types of networks ► Classification ► OSI Model ► TCP/IP vs OSI ► Network Acces ► IEEE Standards ► Transmission media ► Transmission techniques ► Disturbances ► Services and Functions ► Internet ► IPv4 ► ARP ► Netplan ► Routing 2 Network systems ► Transport ► Function, Services and Primitives ► Public and Private keys ► SSH ► Application ► SCP and RCP ► LZW ► DNS ► DHCP
  • 3. Introduction ► Data ► Computers, Printers, scanner, to sum up devices. 3 The target is Share resources! ► Between peers or through the world. ► Reliably and Safely. The challenge is connect devices. Client Server Network JavaScript PHP
  • 5. I. Bit transmission system II. Keep link without error III. Routing and congestion control IV. Connection peer to peer V. Improvement services peer to peer and reconnection without error VI. Compressing data, encryption, manage syntax and semantic VII. Allow user protocols and processes 5 Open System Interconnection treat separately: OSI basic reference model described in ISO 7498-1 (1984) Application Presentation Session Transport Network Data Link Physical Application Presentation Session Transport Network Data Link Physical Network Data Link Physical Network Data Link Physical Protocols Data unit (PDU) N to N Services N to N+1 “Divide and Conquer.”
  • 7. Type of networks ► Body area network BAN ► Personal area network PAN ► Local area network LAN ► Campus area network CAN ► Metropolitan area network MAN ► Wide area network WAN 7 According to size: Classification ► Server-Client ► Peer-to-Peer According to services: BAN PAN LAN CAN MAN WAN
  • 8. 8 ► BUS ► STAR ► RING ► MESH ► TREE According to topology: Font:https://www.assignmenthelp.net/assignment_help/network-topology-and-types
  • 9. 9 Network Acces ► Type of signals ► Electrical parameters Physical interconnection Physical and Data Link OSI Model ► Communication protocols ► Detection and error correction ► Compatibility Logical specification Telematics Remote communication techniques Communications ► Simplex ► Duplex ► SemiDuplex Transmitter Channel Receiver Disturbances Signals ► Sincronus / Asincronus ► Digital / Analog ► Baseband / Modulated ► Serial / Paralel
  • 10. 802.6 Optical FIber 802.15 Bluetooth MEDIA ACCES CONTROL 10 IEEE STANDARDS 802.1 Management 802 General view 802.3 CSMA/CD Ethernet 802.4 Token Bus 802.5 Token Ring 802.11 WLAN 802.11 IR 802.11 FHSS .11a OFDM .11b DSS .11g DSS OFDM 802.2 Logical Link Control LLC LLC Data Link PDU: Frame Physical PDU: Bit 802.16 Wimax SONET SDH RS-232 (Recommended Standard 232) DTE Data terminal Equipment DCE Data Circuitering Equipment DB25 DB25 Modem Telephone Network Physical example protocol ► Modulation ► Synchronisation ► Init and end ► Multiplexing ► Carrier Detection ► Filtering and Equalization Services: ► Peer to Peer / Multicast ► Duplex/Semi Duplex/Simplex ► Electronics /Optical/Mechanical ► Topology ► Serial / Paralel Functions:
  • 11. ► Guided ► Twisted pair (Unshielded UTP or Shielded STP) ► Coaxial 50Ω or 75Ω ► Optical Fiber ► Not guided ► Microwave ► Infrared ► Others (LIFI, HF etc) 11 Transmission media P1 P3 P4 P2 1 2 3 4 5 6 7 8 RJ-45 Font:https://www.pinterest.es Cat 5 100Mbps Carry 100MHz Cat 5e 1Gbps Carry 100MHz Cat 7 10Gbps Carry 600MHz +Shield Cat 8 25Gbps Carry 2000MHz Cat 6 1Gbps Carry 250MHz +Performance Font:https://miracomosehace.com/
  • 13. ► Guided ► Twisted pair (Unshielded UTP or Shielded STP) ► Coaxial 50Ω or 75Ω(TV) ► Optical Fiber ► Not guided ► Microwave ► Infrared ► Others (LIFI, HF etc) 13 Transmission media Font:https://miracomosehace.com/ COAXIAL Bandwidth 500MHz 10-Base 5 RG-8,RG-9,RG-11 10Mbps 500m 10-Base 2 RG-58A/U 10Mbps 200m Bell Labs wave machine
  • 14. ► Guided ► Twisted pair (Unshielded UTP or Shielded STP) ► Coaxial 50Ω or 75Ω(TV) ► Optical Fiber ► Multimode ► Monomode ► Not guided ► Microwave ► Infrared ► Others (LIFI, HF etc) 14 Transmission media Snell’s law Coating Core (n1) Cladding (n2) If All signal are reflected Font:https://www.profesionalreview.com/redes/
  • 15. ► Guided ► Twisted pair (Unshielded UTP or Shielded STP) ► Coaxial 50Ω or 75Ω(TV) ► Optical Fiber ► Not guided ► Microwave ► Right of way allowed ► Poor performance with obstacles ► Authorization required ► Infrared ► Others (LIFI, HF etc) 15 Transmission media Font:https://www.forbes.com/ >1GHz travel straight
  • 16. Font:https://mandoadistanciaparatv.com/ ► Guided ► Twisted pair (Unshielded UTP or Shielded STP) ► Coaxial 50Ω or 75Ω(TV) ► Optical Fiber ► Not guided ► Microwave ► Infrared ► Others (LIFI, HF, etc) 16 Transmission media Font:https://movitherm.com/knowledgebase/thermal-infrared-imaging-explained/ Font:https://support.polar.com/
  • 17. 17 ► Base Band ► Modulated Band ► Digital Modulations ► Multiple access Transmission techniques
  • 18. 18 ► Base Band ► Modulated Band ► Digital Modulations ► Multiple access Transmission techniques
  • 19. 19 ► Base Band ► Modulated Band ► Digital Modulations ► Multiple access Transmission techniques People from other class who don't known Complex numbers
  • 20. 20 ► Base Band ► Modulated Band ► Digital Modulations ► Multiple access ► Time Division Multiple Access TDMA ► Frequency Division Multiple Access ► Code Division Multiple Acces ► TDMA/FDMA ► Spread Spectrum Multiple Access SSMA ► Direct Sequence Spread Spectrum DSSS ► Frequency Hopping FHSS Transmission techniques
  • 21. 21 ► Atenuattion ► Distortion phase or frequency ► Noise ► Thermal (Electronics components) ► Intermodulation (Other frequencies) ► Crosstalk ► Impulsive (Spikes) ► Echoes(multipath) Disturbances C = 2B log2 M Where C = Capacity of the channel B = Bandwidth M = Number of discrete signal or voltage level S = Signal N = Noise C = B log2(1+S/N) bps Nyquist f>=2B Shannon Font:https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem A (dB) = 10 log10 (PotT/PotR) Where A = Attenuation PotT = Power Transmitted PotR = Power Received AΠ(t/T) T t Echo 1/T , 2/T , 3/T ... ATsinc(fT) f x0·Π(t/T) x1·Π(t/T)· e^(j2Πt1/T) ... xn·Π(t/T) · e^(j2ΠtN/T)
  • 22. 802.6 Optical FIber 802.15 Bluetooth MEDIA ACCES CONTROL 22 IEEE STANDARDS 802.1 Management 802 General view 802.3 CSMA/CD Ethernet 802.4 Token Bus 802.5 Token Ring 802.11 WLAN 802.11 IR 802.11 FHSS .11a OFDM .11b DSS .11g DSS OFDM 802.2 Logical Link Control LLC LLC Data Link PDU: Frame Physical PDU: Bit 802.16 Wimax SONET SDH ► Framework ► Error control ► Connection Oriented ► Flow control ► Offline services ► Not Flow control Services: ► Error detection and correction ► Fragmentation and defragmentation ► Media access control Functions: Paritty Generator (k bits) n bits n+k bits Transmission Splitter Paritty Generator (k’’ bits) k’’ bits k’’==k’ k’ bits n’ bits No, Error! Yes Receiver
  • 23. m clk c1 c0 00 10 01 11 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 0/00 1/11 c= 00 00 11 10 10 00 01 01 10 10 m=00110 r= 00 01 01 10 10 r= c+Error Redundancy generator Reception with error Path with less cost (Hamming distance) give us the correct code 0 2 1 1 R1 R0 if m=1 c=11 then 1/11 Viterbi Algorithm Hamming distance 00 11 2 01 11 1 11 01 1 00 10 01 11 0 1 1 0 0 1 1 2 0/01 1/10 R0 R1 4 0/00 0/00 1/ 1/ 0/ Generator 1
  • 24. 24 ► Connection Oriented ► Establishing the link connection ► Data transmission ► Termination of the link connection ► Ensures reliable delivery of frames ► Transmission errors are detected and bad frames are discarded ► All lost or erroneous frames are retransmitted ► All duplicate frames are detected and discarded ► Frames are delivered to the top layer neat and error free ► The flow control is performed between the emitter and the receiver ► To carry out error handling: ► Error detection techniques ► Frame numbering ► Confirmation of all frames received correctly ► Retransmission unconfirmed frames HDLC (High-level Data Link Control): ► Use ► Cisco devices ► Networks with high error rates. 01111110
  • 25. 25 ► Offline services Not guarantee reliable delivery of frames ► Transmission errors are detected and bad frames are discarded ► Missing or erroneous frames are not retransmitted ► Correct frames are not confirmed ► Possible duplicate frames are not detected or discarded ► Frames are delivered to the top layer in the order they arrive ► No flow control between emitter and receiver No establishment or connection end phases ► Each frame is considered independent of the rest ► Use ► Networks with low error rates (these are the most common today) ► ADSL (PPPoE = PPP over Ethernet, PPPoA = PPP over ATM) PPP (Point to point) and LLC (Logic Link Control) protocol: MAC Address
  • 26. 26 ► MAC-48 deprecated ► EUI-48 2^48 (281.474.976.710.656) ► EUI-64 add 16 bits more (RFC 2464) Media Access Control Address (MAC Address)
  • 27. 27 Internet Network OSI Model PDU:Packet or Datagram ► All components has IP address ► Identify Network and Host Addressing ► All component is routed to destination using tables and rules. Routing ► IPv4 RFC791 ► IPV6 IP addressing Classless Inter-Domain Routing (CIDR)
  • 28. 28 ► 32 to be grouped in eights ► RFC5735 Classes and reserved addresses ► A mask is used to known Network or Host bits ► Some are Private IPs RFC1918: ► Class A ► 10.0.0.0 to 10.255.255.255 ► Class B ► 172.16.0.0 to 172.31.255.255 ► Class C ► 192.168.0.0 to 192.168.255.255 ► Loopback RFC1122: ► 127.0.0.0 to 127.255.255.255 ► Link-Local RFC3927: ► 169.254.1.0 to 169.254.254.255 ► Multicast RFC1122: ► 224.0.0.0 to 224.0.0.15 ► Future RFC1122: ► 240.0.0.0 to 240.0.0.15 ► Broadcast RFC919: ► 255.255.255.255/32 IPv4 ► Class A ► 0.0.0.0 to 127.255.255.255 Mask 255.0.0.0 ► Class B ► 128.0.0.0 to 191.255.255.255 Mask 255.255.0.0 ► Class C ► 192.0.0.0 to 223.255.255.255 Mask 255.255.255.0 ► Class D ► 224.0.0.0 to 239.255.255.255 ► Class E ► 240.0.0.0 to 255.255.255.255
  • 29. 29 Classe Extended mask Reduced mask Binary mask Wildmask A 255.0.0.0 /8 11111111.00000000.00000000.00000000 0.255.255.255 B 255.255.0.0 /16 11111111.11111111.00000000.00000000 0.0.255.255 C 255.255.255.0 /24 11111111.11111111.11111111.00000000 0.0.0.255 Net Address Mask First Host Address Last Host Address Broadcast Address Nº Hosts 147.23.0.0 255.255.0.0 147.23.0.1 147.23.255.254 147.23.255.255 2^16 – 2 = 65534
  • 31. 31 Address Resolution Protocol (ARP) RFC 826 and RFC 5227 / 5494. I’m ready to sent to print for first time!. -The printer’s IP = 192.168.0.29 - ► Host: Hey there (sending to FF:FF:FF:FF:FF:FF) Who has ? 192.168.0.29 ► Printer: to host...Hey! 192.168.0.29 is at 14:2d:27:bc:46:4d Ok noted! Now I can send data to print to 14:2d:27:bc:46:4d
  • 32. 32 ► systemctl stop network-manager ► systemctl start network-manager ► systemctl disable network-manager ► systemctl enable network-manager ► systemctl mask network-manager ► systemctl unmask network-manager NetworkManager
  • 33. 33 Network Manager has nmcli to management $ nmcli con add con-name eth1 type wifi ifname eth1 ipv4.method auto $ nmcli con mod eth1 ipv6.method ignore $ nmcli con edit $ nmcli con reload # nmcli radio # nmcli device wifi rescan # nmcli device wifi list # nmcli device wifi connect SSID-Name password wireless-password
  • 34. 34 Dijkstra algorithm for dynamic routing STEP NODES A B C D 0 0 inf/- inf/C inf/- 1 - 7/A 3/A inf/- 2 - 5/C - 11/C 3 - - - 7/B A C B D 3 7 2 2 8
  • 35. 35 Transport Transport OSI Model PDU:Segment or Datagram ► Fragmentation / Defragmentation ► Multiplexing / Demultiplexing ► Flow Control ► Error Control Functions ► Connection Oriented (TCP) ► Establishment ► Transferring ► Release connection ► Connectionless Communication (UDP) Services ► LISTEN ► CONNECT ► SEND ► RECEIVE ► DISCONNECT Host A Host B time Host A Host B time Primitives
  • 36. 36 ► Provides a secure channel over an unsecured network ► Use public and private key i useful to scripting SSH (Secure Shell) type $env:USERPROFILE.sshid_rsa.pub | ssh pi@IP_ADDRESS "cat >> .ssh/authorized_keys" ssh -X <user_name>@<ip_addres> -p <port> Get-Service sshd Start-Service sshd Stop-Service sshd cssh netadmin@192.168.1.{1..254} $ sudo systemctl start ssh $ sudo nano /etc/ssh/sshd_config $ sudo systemctl reload ssh scp .ssh/id_rsa.pub teacher@IP_ADDRESS:"C:ProgramDatasshadministrators_authorized_keys"
  • 37. 37 Application Session OSI Model PDU: Transaction or Datagram ► Access point to services ► Establishment ► Release connection Functions ► SCP Secure copy ► Authentication less (SSH do it) ► Encrypted data ► RCP Remote copy files ► rcp [-r] source-file|directory target-file|directory Services
  • 38. 38 Application Presentation OSI Model PDU: Datagram ► Data format ► Encryption ► Compression ► MP3, JPEG, AVI, Lemple-Ziv- Welch(LZW) Functions
  • 39. 39 TOBEORNOTTOBEORTOBEORNOT # LZW # A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 TEXT CODE T 20 O 15 B 2 E 5 O 15 R 18 N 14 O 15 T 20 TO 28 BE 30 TEXT CODE TO 28 OB 29 BE 30 E0 31 OR 32 RN 33 NO 34 OT 35 TT 36 TOB 37 BEO 38 ORT 39 TOBE 40 RNO 42 OT # 43 TEXT CODE OR 32 TOB 37 EO 31 RN 33 OT 35 # 0 40/15/33/35/37/41/37/41/33/43 there are 10 codes Log2(43)≈5,426 thus 60 bits Alphabet has 27 letters Log2(27)≈ 4,75 thus 135 bits Arround 50% Compression !!
  • 40. 40 Application Application OSI Model PDU: Datagram ► Applications and interfaces ► Show human readable ► Telnet, FTP, DNS, SMTP Functions
  • 41. Dynamic Host Configuration Protocol (DHCP) Under UDP Client sent DHCP Discovery to broadcast and port 67, from IP 0.0.0.0 and port 68 Server sent DHCP Offer to broadcast IP: source=192.168.1.1; destination=255.255.255.255 UDP: source port=67; destination port=68 sudo dhclient -r 41