fundamentos generales
TRANSCRIPT
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Módulo:
Fundamentos de Redes
Maestría en Seguridad
Telemática
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Facilitador Diego Avila Pesántez Estudios:
Ingeniero en Sistemas Informáticos ( UC 1997)
Maestría en Internetworking (U. de Chile 2002)
Diplomado en Docencia Universitaria (2000)
Maestría en Informática Aplicada (ESPOCH
2003)
Estudiante del Doctorado en Ingeniería en
Sistemas e Informática. UMNSM
Certificaciones Internacionales:
CCNA (Cisco Certified Netwok Associete)
CCNP(Cisco Certified Network Proffesional)
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Motivación
http://www.youtube.com/watch?v=itIy8jlVF6o
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Evaluación del Módulo
• Tareas/Labs 50%
• Caso de estudio 50%
Horario de jornadas:
Viernes 17h00 - 22h00
Sábado 08h00 - 17h00
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Agenda
• Conceptos Generales, modelo OSI
& TCP/IP
• Conectividad en función de
capas: Física, Enlace de datos, Red
• Tecnologías de Redes LAN
•Direccionamiento IPv4, IPv6.
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Objetivos del Módulo •Revisar la tecnología actual del entorno de
redes que permita a los asistentes recordar
definiciones y conceptos importantes como
punto de partida a los laboratorios
experimentales.
• Analizar los principios del Modelo de
referencia OSI, TCP/IP, switching Ethernet,
protocolos capa 3 que permitan comparar con
las diferentes aplicaciones y su funcionamiento
estratificado en capas.
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Bibliografía · Isaacs, M. Internet User's Guide to Network Resource Tools:
http://www.terena.nl/gnrt/. Estupenda guía sobre las herramientas y servicios de
Internet. Imprescindible para cualquier usuario habitual u ocasional.
· McKeon, B. An Introduction to the OSI Reference Model:
http://ntrg.cs.tcd.ie/undergrad/4ba2/ . Muy buen resumen del modelo OSI y de los
protocolos OSI. También habla de TCP/IP y ATM.
· Networking Essentials: http://www.labmice.net/networking/networkbasics.htm
· Technology Guides for Communications & Networking:
http://www.techguide.com/. Interesante recopilación de guías técnicas. Hay que
registrarse para conseguirlas, pero es gratis.
· Home Page de Raj Jain: http://www.cis.ohio-state.edu/~jain/. Impresionante
colección de materiales docentes sobre redes (presentaciones, ejercicios, etc.)
· Tutoriales de Network Magazine:
http://www.networkmagazine.com/static/tutorial/index.html. Interesante
recopilación de artículos educativos sobre diversos temas relacionados con redes
de computadores.
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Bibliografía Howe, D. Free On-Line Dictionary Of Computing: http://wombat.doc.ic.ac.uk/.
Recopilación exhaustiva de términos informáticos.
· Malkin, G. (RFC1983). Internet Users' Glossary. Completo diccionario de
términos y abreviaturas del mundo Internet
· Tech Encyclopedia: http://www.techweb.com/encyclopedia/
· Webopedia: http://webopedia.internet.com/
· Whatis: http://whatis.com/
ANSI (American National Standards Institute): http://www.ansi.org/
· ATM Forum: http://www.atmforum.com
· Frame Relay Forum: http://www.frforum.com
· IEEE (Institute of Electrical and Electronic Engineers): http://www.ieee.org
· IETF (Internet Engineering Task Force): http://www.ietf.org
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Local Area Network (LAN)
Local Area Network (LAN)
An individual network usually spans a single
geographical area, providing services and applications
to people within a common organizational structure,
such as a single business, campus or region.
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Wide Area Network (WAN)
Wide Area Networks (WANs)
Leased connections through a telecommunications
service provider network.
Networks that connect LANs in geographically
separated locations
Telecommunications service provider (Carrier)
interconnect the LANs at the different locations.
Voice and data on separate networks or converged
networks
T1, DS3, OC3
PPP, HDLC
Frame Relay, ATM
ISDN, POTS
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End devices
End devices or hosts:
The source or destination of a message.
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Components of the Network
Devices (hardware)
End devices, switch, router, firewall
Media (wired, wireless)
Cables, wireless mediums
Services (software)
Network applications, routing protocols, processes, algorithms
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Servers and Clients
A host
Client, Server, or both.
Software determines the role.
Servers provide information and services to clients
e-mail or web pages
Clients request information from the server.
Server
Client
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Network
Media
Network media: The medium over which the message
travels.
Cooper wires - electrical impulses.
Fiber optics – pulses of light
Wireless – electromagnetic waves.
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Network
Media
Different media considerations (4):
Distance it will carry signal
Environment it works in
Bandwidth (speed)
Cost
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Components of a Network
Topology Diagrams
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New Network Trends
Some of the top trends include:
Bring Your Own Device (BYOD)
Online collaboration
Video
Cloud computing
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Network Trends
Bring Your Own Device (BYOD)
The concept of any device, to any content, in anyway is a major
global trend that requires significant changes to the way devices
are used. This trend is known as Bring Your Own Device (BYOD).
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Online Collaboration
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Video Communication
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Cloud Computing
Cloud computing offers the following potential
benefits:
Organizational flexibility
Agility and rapid deployment
Reduced cost of infrastructure
Refocus of IT resources
Creation of new business
models
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Data Centers A data center is a facility used to house computer
systems and associated components including:
Redundant data communications connections
High-speed virtual servers (sometimes referred to as
server farms or server clusters)
Redundant storage systems (typically uses SAN
technology)
Redundant or backup power supplies
Environmental controls (e.g., air conditioning, fire
suppression)
Security devices
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Networking Technologies for the Home
Technology Trends in the Home
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Networking Technologies for the Home
Powerline Networking
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Networking Technologies for the Home
Wireless Broadband
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Network Security
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Network Security
Security Threats
The most common external threats to networks
include:
Viruses, worms, and Trojan horses
Spyware and adware
Zero-day attacks, also called zero-hour attacks
Hacker attacks
Denial of service (DoS) attacks
Data interception and theft
Identity theft
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Security Solutions Network security components often include:
Antivirus and antispyware
Firewall filtering
Dedicated firewall systems
Access control lists (ACL)
Intrusion prevention systems (IPS)
Virtual Private Networks (VPNs)
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Early days – proprietary network equipment and protocols.
Now – Industry standards
Institute of Electrical and Electronics Engineers (IEEE)
Examples: 802.3 (Ethernet), 802.11 (WLAN)
Internet Engineering Task Force (IETF)
Internet standards
RFCs (Request for Comments)
Example: TCP, IP, HTTP, FTP
Protocol Suites and Standards
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Example: RFC 791 IPv4
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Protocols
Protocol – Rules that govern communications.
Protocol suite - A group of inter-related protocols
Example: TCP/IP
HTTP
Header Data
Frame Header IP Header TCP Header App
Header Frame Trailer
Protocols
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Protocol and Reference Models
The Open Systems Interconnection (OSI) model is the most widely known internetwork reference model.
The International Organization for Standardization (ISO) released the OSI reference model in 1984, was the descriptive scheme they created.
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TCP/IP Model
TCP/IP Model and Protocol Suite is an open standard.
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Multiple protocols (encapsulated)
Encapsulation – Process of adding a header to the data
or any previous set of headers.
Decapsulation – Process of removing a header.
HTTP
Header Data
Frame Header IP Header TCP Header App
Header Frame Trailer
Data
Protocols
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The Communication Process - Encapsulation
Server
Data HTTP
Header
TCP
Header
IP
Header
Data Link
Header
Data Link
Trailer
HTTP Data
Encapsulation – Process of adding control information as
it passes down through the layered model.
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The Communication Process - Decapsulation
Data HTTP
Header
TCP
Header
IP
Header
Data Link
Header
Data Link
Trailer
Client
HTTP Data
Decapsulation – Process of removing control information
as it passes upwards through the layered model.
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The
Communication
Process
Protocol Data Unit (PDU) - The form that a piece of data takes at any layer.
PDUs are named according to the protocols of the TCP/IP suite.
Data - Application layer PDU
Segment - Transport Layer PDU
Packet - Internetwork Layer PDU
Frame - Network Access Layer PDU
Bits - A PDU used when physically transmitting data over the medium
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TAREA EN CLASE: ENCAPSULAMIENTO
Organizarse en equipos de 4 personas.
Determinar la manera como pueden
describir el proceso de encapsulamiento
de datos.
10 min. para planificar la presentación.
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Warriors of the Net
To get an idea of many of the things we will be learning about…
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TCP-IP Protocol
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TCP-IP Protocol
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HTTP
(WWW)
FTP
SMTP
(email)
Telnet
(file transfer)
(remote login)
DHCP
(IP address
resolution)
DNS
(file sharing)
P2P
(domain name
resolution)
(file sharing)
SMB
We will examine
HTTP in detail.
Aplication Layer
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HTTP (HyperText Transfer Protocol)
Implemented in:
Client program
Server program
Web page (also called a html document)
Web page consists of objects
HTML file
JPEG image
JAVA applet
Audio file
HTTP
Server
HTTP
Client
HTTP HTTP
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HTTPS
HTTPS (Hypertext Transfer Protocol over Secure Socket Layer) is a URL
scheme used to indicate a secure HTTP connection.
HTTPS is not a separate protocol
combination of a normal HTTP interaction over an encrypted:
Secure Sockets Layer (SSL) or
Transport Layer Security (TLS) connection
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FTP (File Transfer Protocol)
FTP was developed to allow for file transfers between a client and a server.
Used to push and pull files from a server running the FTP daemon (FTPd).
RFC 959
FTP
Client FTP
Server
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Internet mail involves:
User agents
Allows users to read, reply, compose, forward, save, etc., mail messages
GUI user agents: Outlook, Eudora, Messenger
Text user agents: mail, pine, elm
Mail servers
Stores user mail boxes, communicates with local user agents and other
mail servers.
SMTP
Principle application layer protocol for Internet mail
Sent over TCP
Mail access protocols: POP3, IMAP4, HTTP
SMTP SMTP
POP3
IMAP
User agent User agent Mail server Mail server
SMTP – Simple Mail Transfer Protocol
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Telnet
Allows a user to remotely access another device (host, router,
switch).
Connection called a Virtual Terminal (VTY) session.
Telnet clients:
Putty
Teraterm
Hyperterm
Server
Telnet Telnet
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Telnet
Supports user authentication,
Does not encrypt data.
Secure Shell (SSH) protocol offers an alternate and secure method for
server access.
Stronger authentication
Encrypts data
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DHCP – Dynamic Host Configuration Protocol
IP addresses and other information can be obtained:
Statically
Dynamically (DHCP)
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DNS – Domain Name System
DNS allows users (software) to use domain names instead of IP addresses
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Transport Layer Protocols
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0 15 16 31
16-bit Source Port Number
16-bit Destination Port Number
32-bit Sequence Number
32 bit Acknowledgement Number
4-bit Header
Length
6-bit
(Reserved)
U
R
G
A
C
K
P
S
H
R
S
T
S
Y
N
F
I
N
16-bit Window Size
16-bit TCP Checksum
16-bit Urgent Pointer
Options (if any)
Data (if any)
UDP and TCP TCP
TCP provides:
Reliable delivery
Error checking
Flow control
Congestion control
Ordered delivery
(Connection establishment)
UDP provides:
Unreliable delivery
No error checking
No flow control
No congestion control
No ordered delivery
(No connection establishment)
UDP
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TCP Header
TCP provides reliable delivery on top of unreliable IP
0 15 16 31
16-bit Source Port Number
16-bit Destination Port Number
32-bit Sequence Number
32 bit Acknowledgement Number
4-bit Header
Length
6-bit
(Reserved)
U
R
G
A
C
K
P
S
H
R
S
T
S
Y
N
F
I
N
16-bit Window Size
16-bit TCP Checksum
16-bit Urgent Pointer
Options (if any)
Data (if any)
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TCP Header
source port -- the number of the calling port
destination port -- the number of the called port
sequence number -- the number used to ensure correct sequencing of the arriving data
acknowledgment number -- the next expected TCP octet
HLEN -- the number of 32-bit words in the header
reserved -- set to 0
code bits -- the control functions (e.g. setup and termination of a session)
window -- the number of octets that the sender is willing to accept
checksum -- the calculated checksum of the header and data fields
urgent pointer -- indicates the end of the urgent data
option -- one currently defined: maximum TCP segment size
data -- upper-layer protocol data
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TCP: Connection Establishment 0 15 16 31
16-bit Source Port Number
16-bit Destination Port Number
32-bit Sequence Number
32 bit Acknowledgement Number
4-bit Header
Length
6-bit
(Reserved)
U
R
G
A
C
K
P
S
H
R
S
T
S
Y
N
F
I
N
16-bit Window Size
16-bit TCP Checksum
16-bit Urgent Pointer
Options (if any)
Data (if any)
Three-way
Handshake
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TCP: Connection Termination
1. When the client has no more data to send in the stream, it sends a segment
with the FIN flag set.
2. The server sends an ACK to acknowledge the receipt of the FIN to terminate
the session from client to server.
3. The server sends a FIN to the client, to terminate the server to client session.
4. The client responds with an ACK to acknowledge the FIN from the server.
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UDP
source port -- the number of the calling port
destination port -- the number of the called port
UDP length -- the length of the UDP header
checksum -- the calculated checksum of the header and data fields
data -- upper-layer protocol data
0 15 16 31
16-bit Source Port Number
16-bit Destination Port Number
16-bit UDP Length
16-bit UDP Checksum
Data (if any)
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UDP
Why would an application developer choose UDP rather than TCP?
Finer application-layer control
TCP will continue to resend segments that are not acknowledged.
Applications that use UDP can tolerate some data loss:
Streaming video
VoIP (Voice over IP)
Application decides whether or not to resend entire file: TFTP
0 15 16 31
16-bit Source Port Number
16-bit Destination Port Number
16-bit UDP Length
16-bit UDP Checksum
Data (if any)
Time
Client Server
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Network Layer
IPv4
IPv6
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Network Layer
Layer 3 uses four basic processes:
Addressing
Encapsulation
Routing
Decapsulation
0 15 16 31
4-bit
Version
4-bit
Header
Length
8-bit Type Of
Service
(TOS)
16-bit Total Length (in bytes)
16-bit Identification
3-bit
Flags
13-bit Fragment Offset
8 bit Time To Live
TTL
8-bit Protocol
16-bit Header Checksum
32-bit Source IP Address
32-bit Destination IP Address
Options (if any)
Data
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Assignment of IP Addresses
Regional Internet Registries (RIRs)
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IP Header IPv4
IP Destination Address
32-bit binary value that represents the packet destination
Network layer host address.
IP Source Address
32-bit binary value that represents the packet source Network
layer host address.
Where I am
going.
Where I came
from.
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Sending hosts generates the value for TTL.
Common operating system TTL values are:
UNIX: 255
Linux: 64 or 255 depending upon vendor and version
Microsoft Windows 95: 32
Microsoft Vista: 128
Protocol field enables the Network layer to pass the data to the
appropriate upper-layer protocol.
Example values are:
01 ICMP, 06 TCP, 17 UDP
Type-of-Service is used to determine the priority of each packet.
Enables Quality-of-Service (QoS) mechanism for high priority traffic.
What types of traffic might a network administrator need to give priority
to? Traffic that cannot accept any delays.
VoIP, Streaming video
IP Header IPv4
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Special Use IPv4 Addresses
Network and Broadcast addresses – within each
network the first and last addresses cannot be assigned
to hosts
Loopback address – 127.0.0.1 a special address that
hosts use to direct traffic to themselves (addresses
127.0.0.0 to 127.255.255.255 are reserved)
Link-Local address – 169.254.0.0 to 169.254.255.255
(169.254.0.0/16) addresses can be automatically
assigned to the local host
Experimental addresses – 240.0.0.0 to
255.255.255.254 are listed as reserved
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Public and Private IPv4 Addresses
Private address blocks are:
Hosts that do not require access to the Internet can use private
addresses
10.0.0.0 to 10.255.255.255 (10.0.0.0/8)
172.16.0.0 to 172.31.255.255 (172.16.0.0/12)
192.168.0.0 to 192.168.255.255 (192.168.0.0/16)
Shared address space addresses:
Not globally routable
Intended only for use in service provider networks
Address block is 100.64.0.0/10
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Public and Private IPv4 Addresses
Private address blocks are:
Hosts that do not require access to the Internet can use
private addresses
10.0.0.0 to 10.255.255.255 (10.0.0.0/8)
172.16.0.0 to 172.31.255.255 (172.16.0.0/12)
192.168.0.0 to 192.168.255.255 (192.168.0.0/16)
Shared address space addresses:
Not globally routable
Intended only for use in service provider networks
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Network/Subnets Address
Networks can be subdivided into subnets.
This provides for several benefits which we will discuss later.
Networks can be grouped based on factors that include:
Geographic location, Purpose, Ownership
172.16.10.100/24
172.16.10.55/24
172.16.10.3/24
172.16.20.77/24
172.16.20.96/24
172.16.20.103/24
172.16.30.39/24
172.16.30.10/24
172.16.30.111/24
172.16.40.123/24
172.16.40.51/24
172.16.40.29/24 172.16.1.1/24
172.16.10.1/24 172.16.20.1/24 172.16.30.1/24 172.16.40.1/24
172.16.10.0/24 172.16.20.0/24 172.16.30.0/24 172.16.40.0/24
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Static routes
Manually entered by the administrator
Dynamic Routing protocols
Routers automatically learn about remote networks
Ex: RIP, EIGRP, OSPF, IS-IS, BGP
192.168.1.254/24
C 192.168.2.0/24 is direction connected, FastEthernet0/1
Network 192.168.2.0/24
Network 192.168.1.0/24
Routing
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IPv6 Addressing
128-bit hexadecimal format (0-9, A-F)
Uses 16-bit hexadecimal number fields separated by
colons (:)
Every 4-hexadecimal digits are equivalent to 16-bits.
Consists of 8 hextets/quartets which is the equivalent to 16-
bits per-hextet.
2001:0DB8:0001:5270:0127:00AB:CAFE:0E1F /64
- 2001 in hexadecimal is 0010 0000 0000 0001 in
binary
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IPv6 Addressing Structure
The Site Prefix or Global Routing Prefix is the first 3
hextets or 48-bits of the address. It is assigned by the
service provider.
The Site Topology or Subnet ID Is the 4th hextet of the
address.
The Interface ID is the last 4 hextets or 64-bits of the
address. It can be manually or dynamically assigned using
the EUI-64 command. (Extended Unique Identifier)
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IPv6 Addressing Structure
First 3 bits are fixed at 001 or 200::/12 (IANA Global
Routing Number)
Bits 16-24 identifies the Regional Registry:
- AfriNIC, APNIC, LACNIC, RIPE NCC and ARIN
2001:0000::/23 – IANA
2001:0200::/23 – APNIC (Asia/Pacific Region)
2001:0400::/23 – ARIN (North America Region)
2001:0600::/23 – RIPE (Europe, Middle East and Central Asia)
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IPv6 Addressing Structure
Remaining 8-bits up to /32 identifies the ISP.
The 3rd hextet represents the Site/Customer Identifier.
The 4th hextet represent the Site Topology/Subnet ID.
- Allows 65,536 subnets with 18,446,744,073,709,551,616 (18
quintillion) for each subnet.
- Not part of the host address field.
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IPv6 Addressing Scheme and Subnets
The Interface ID are the remaining 64-bits of the address.
Can be manually configured or dynamically by using the EUI-64
(Extended Unique Identifier).
The EUI-64 command uses the device 48-bits MAC Address and
convert it into 64-bits by adding FF:FE in the middle of the address.
The first (network) and last (broadcast) address may be assigned to an
interface. An interface may contain more than one IPv6 address.
There are no broadcast addresses, multicast is used instead.
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IPv6 Addressing Scheme and Subnets
IPv6 uses the same method as IPv4 to subnet their
addresses.
/127 gives you 2 addresses.
/124 gives you 16 addresses
/120 gives you 256 addresses
The first address in a network consists of all 0's and the last
address consists of all F's.
It’s recommended for simplicity and design purposes to use
/64 everywhere. Using anything less than /64 could
potentially break IPv6 features and cause increased design
complexity.
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Leading Zeroes and Double Colons (::)
Leading 0s (zeroes) in any 16-bit section can be omitted.
Address before omission:
2001:0DB8:0001:5270:0127:00AB:CAFE:0E1F /64
Address after omission:
2001:DB8:1:5270:127:AB:CAFE:E1F /64
This rule applies only to leading 0s; if trailing 0s are omitted, the
address would be vague.
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Leading Zeroes and Double Colons (::)
A Double Colons or Compressing Zeroes can be used to shorten an
IPv6 address when one or more hextets consist of all 0s.
Double Colons can only be used to compress a single contiguous 16-
bits blocks. You cannot use double colons to include part of a block.
Double Colons can only be used once in an address, if it's used more
than once the address could be ambiguous
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Data Link Layer
Data Link layer
Connects the Network Layer with the Physical Layer
Network Layer and above is software (IP, TCP, HTTP, etc.)
Physical layer is implemented in hardware (converting bits to a transmission signal)
Data Link layer is implemented in both:
Software
Hardware
Data Link Layer prepares Network Layer packets for transmission across some form of media, be it copper, fiber, or the atmosphere.
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Data Link Sublayers
Data Link layer has two sublayers (sometimes):
Logical Link Control (LLC) – Software processes that provide
services to the Network layer protocols.
Frame information that identifies the Network layer protocol.
Multiple Layer 3 protocols, (IP and IPX) can use the same
network interface and media.
Media Access Control (MAC) - Media access processes
performed by the hardware.
Provides Data Link layer addressing and framing of the data
according to the protocol in use.
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79
Media Access Control
The media access control methods used by logical
multi-access topologies are typically:
CSMA/CD - Hubs
CSMA/CA - Wireless
Token passing – Token Ring
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Physical Layer Protocols & Services
Describe the purpose of the Physical layer in the network and
identify the basic elements that enable this layer to fulfill its
function
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Physical Layer Protocols & Services
Describe the role of bits in representing a frame as it is
transported across the local media
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Physical Layer Protocols & Services
Describe the role of signaling in the physical media
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Physical Layer Protocols & Services
Identify hardware components associated with the Physical layer
that are governed by standards
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Characteristics & Uses of Network Media
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Coaxial Cable
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Coaxial Cable
Advantages:
Less expensive than fiber
It has been used for many years for many types of data communication, including cable television
Disadvantages:
More expensive and more difficult to install than twisted pair
Needs more room in wiring ducts than twisted pair
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Shielded Twisted Pair (STP and ScTP)
Shielded twisted-pair cable (STP) combines the techniques of shielding, cancellation, and twisting of wires.
Each pair of wires is wrapped in metallic foil.
The four pairs of wires are wrapped in an overall metallic braid or foil.
A new hybrid of UTP with traditional STP is Screened UTP (ScTP), also known as Foil Twisted Pair (FTP).
ScTP is essentially UTP wrapped in a metallic foil shield, or screen.
STP – Shielded Twisted Pair ScTP – Screened Twisted Pair
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Shielded Twisted Pair (STP and ScTP)
Greater protection from all types of external and internal interference than UTP.
Reduces electrical noise within the cable such as pair to pair coupling and crosstalk.
Reduces electronic noise from outside the cable, for example electromagnetic interference (EMI) and radio frequency interference (RFI).
More expensive and difficult to install than UTP.
Needs to be grounded at both ends
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Characteristics & Uses of Network Media
Unshielded twisted-pair cable (UTP) is a four-pair wire medium used in
a variety of networks.
TIA/EIA-568-B contains specifications governing cable performance.
RJ-45 connector
When communication occurs, the signal that is transmitted by the
source needs to be understood by the destination.
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Characteristics & Uses of Network Media
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ST and SC Connectors
The type of connector most commonly used with multimode
fiber is the Subscriber Connector (SC connector).
On single-mode fiber, the Straight Tip (ST) connector is
frequently used.
LC (Little conector).
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Fiber versus Copper
Implementation Issues Copper Media Fibre Optic
Bandwidth Supported 10 Mbps – 10 Gbps 10 Mbps – 100 Gbps
Distance Relatively short
(1 – 100 meters)
Relatively High
(1 – 100,000 meters)
Immunity To EMI And RFI Low High
(Completely immune)
Immunity To Electrical Hazards Low High
(Completely immune)
Media And Connector Costs Lowest Highest
Installation Skills Required Lowest Highest
Safety Precautions Lowest Highest
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Properties of Wireless Media
Wireless does have some areas of concern including:
Coverage area
Interference
Security
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• IEEE 802.11 standards
• Commonly referred to as Wi-Fi.
• Uses CSMA/CA
• Variations include:
• 802.11a: 54 Mbps, 5 GHz
• 802.11b: 11 Mbps, 2.4 GHz
• 802.11g: 54 Mbps, 2.4 GHz
• 802.11n: 600 Mbps, 2.4 and 5 GHz
• 802.11ac: 1 Gbps, 5 GHz
• 802.11ad: 7 Gbps, 2.4 GHz, 5 GHz, and 60 GHz
• IEEE 802.15 standard
• Supports speeds up to 3 Mb/s
• Provides device pairing over distances from 1 to 100
meters.
• IEEE 802.16 standard
• Provides speeds up to 1 Gbps
• Uses a point-to-multipoint topology to provide
wireless broadband access.
Wireless Media
Types of Wireless Media
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Wireless Media
Wireless LAN
Cisco Linksys EA6500 802.11ac Wireless Router
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Wireless Media
802.11 Wi-Fi Standards
Standard Maximum
Speed Frequency
Backwards
Compatible
802.11a 54 Mbps 5 GHz No
802.11b 11 Mbps 2.4 GHz No
802.11g 54 Mbps 2.4 GHz 802.11b
802.11n 600 Mbps 2.4 GHz or 5 GHz 802.11b/g
802.11ac 1.3 Gbps
(1300 Mbps)
2.4 GHz and 5.5
GHz 802.11b/g/n
802.11ad 7 Gbps
(7000 Mbps)
2.4 GHz, 5 GHz and
60 GHz 802.11b/g/n/ac
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How wireless LANs communicate
Since radio frequency (RF) is a
shared medium, collisions can
occur just as they do on wired
shared medium.
The major difference is that there is
no method by which the source
node is able to detect that a
collision occurred.
For that reason WLANs use Carrier
Sense Multiple Access/Collision
Avoidance (CSMA/CA).
This is somewhat like Ethernet
CSMA/CD.
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Tarea Extraclase:
Realizar un mapa mental sobre características de cables: UTP/STP Cat 5e, Cat 6, Cat 6A, Cat 7, Fibra óptica multimodo, Fibra óptica monomodo.
Stack de protocolos que utiliza la aplicación VoIP utilizando Wireshark.
Simulación de la red de Campus utilizando el Packet Tracer de Cisco.