Capa 1 2 3

7/30/2019 Capa 1 2 3

1/63

Periodo 2013

GESTION DE REDESAREA DE LA ENERGA LAS INDUSTRIAS

Y LOS RECURSOS NATURALES NO

RENOVABLESCARRERA DE INGENIERA EN SISTEMAS

GESTION DE REDES Parte III

7/30/2019 Capa 1 2 3

2/63

MEDIOS FISICOS

7/30/2019 Capa 1 2 3

3/63

Se enfocar a los medio de red ms comunes y sus caractersticas,describiremos entonces:

Cable STP

Cable UTP

Cable Coaxial

Fibra pticaAtmsfera (redes inalmbricas)

MEDIOS FISICOS

7/30/2019 Capa 1 2 3

4/63

CableSpecifications

Cables have different specifications and expectations pertaining toperformance.

7/30/2019 Capa 1 2 3

5/63

Coaxial Cable

7/30/2019 Capa 1 2 3

6/63

Coaxial Cable

Advantages: Requires fewer repeaters than twisted pair 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 thantwisted pair

Needs more room in wiring ducts than twisted pair

7/30/2019 Capa 1 2 3

7/63

Unshielded Twisted Pair (UTP)

Unshielded twisted-pair cable (UTP) is a four-pair wiremedium used in a variety of networks.

TIA/EIA-568-A/B contains specifications governing cable

performance. RJ-45 connector

When communication occurs, the signal that is transmitted bythe source needs to be understood by the destination.

7/30/2019 Capa 1 2 3

8/63

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. 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

7/30/2019 Capa 1 2 3

9/63

Fiber Optic Cabling

7/30/2019 Capa 1 2 3

10/63

ST and SC Connectors

The type of connector most commonly used withmultimode fiber is the Subscriber Connector (SC

connector); LC connector smaller than the sc , FCReplacement by ST Y SC

On single-mode fiber, the Straight Tip (ST)connector is frequently used. MT-Array (array defiber)

7/30/2019 Capa 1 2 3

11/63

Fiber Optic Patch Panel

7/30/2019 Capa 1 2 3

12/63

Medio inalmbrico Ondas electromagnticas, que pueden recorrer el

vaco del espacio exterior y medios como el aire.

No necesitan un medio fsico para propagarse. Muy verstil para el desarrollo de redes. La aplicacin ms comn de las comunicaciones de

datos corresponde a los usuarios mviles. Cualquier persona o elemento que necesite

comunicar datos a travs de una red sin laslimitaciones de la FO o el cobre .

7/30/2019 Capa 1 2 3

13/63

Wireless WAN Standards IEEE is the prime issuer of standards for wireless

networks. 802.11 standard is Direct Sequence Spread Spectrum

(DSSS). DSSS applies to wireless devices operating within a 1

to 2 Mbps range.

802.11b may also be called Wi-Fi or high-speedwireless and refers to DSSS systems that operate at 1, 2,5.5 and 11 Mbps. The majority of 802.11b devices still fail to match the

11 Mbps throughput and generally function in the2 to4 Mbps range.

802.11acovers WLAN devices operating in the 5 GHZtransmission band. throughput 54 Mbit/s

802.11g provides the same throughout as 802.11a butwith backwards compatibility for 802.11b devices.

802.11 n provides throughout as 300 Mbps

7/30/2019 Capa 1 2 3

14/63

Wireless devices

7/30/2019 Capa 1 2 3

15/63

How wireless LANscommunicate

Since radio frequency (RF) is a sharedmedium, collisions can occur just as theydo on wired shared medium.

The major difference is that there is nomethod by which the source node is ableto detect that a collision occurred.

For that reason WLANs use Carrier

Sense Multiple Access/CollisionAvoidance (CSMA/CA). This is somewhat like Ethernet

CSMA/CD.

7/30/2019 Capa 1 2 3

16/63

Prctica: Utilizar el software Packet Tracer 5.0 o mas

para simulacin de una red de campus condiferentes tipos de medios de comunicacin

con WLAN con APs y laptops.

7/30/2019 Capa 1 2 3

17/63

Tecnologas de la Capa 2 Desempea funciones especficas como:

Proporcionar una interfaz de servicio biendefinida para la capa de red.

Determinar la manera como los bits seagrupan en tramas, suministrando trnsitode datos confiable a travs del enlace fsicoutilizando las direcciones MAC.

Manejar los errores de transmisin y Regularel flujo de tramas para que los

receptores lentos no sean saturados por

transmisores rpidos.

7/30/2019 Capa 1 2 3

18/63

Capa de Enlace de Datos

7/30/2019 Capa 1 2 3

19/63

Implementaciones Prcticas Token Ring, FDDI y Ethernet. Todas especifican

aspectos de la Capa 2 (LLC control de enlacelgico, denominacin, entramado y MAC), as comotambin aspectos de los componentes desealizacin y de medios de la Capa 1.

Ethernet: topologa de bus lgica y en estrella fsicao en estrella extendida.

Token Ring: topologa de anillo lgica y unatopologa fsica en estrella.

FDDI: topologa de anillo lgica y topologa fsica deanillo doble.

7/30/2019 Capa 1 2 3

20/63

Entramado o Enmarcado de

Datos Para entregarservicios a la Capa de red, la

Capa de enlace de Datos debe utilizarlos

servicios proporcionados por la Capa fsica. La capa 1 acepta un flujo de bits en bruto y lo

entrega al destino o intenta hacerlo y nogarantiza ausencia de errores.

El # de bits recibidos puede ser mayor, menoroigualque el # de bits transmitidos.

Es responsabilidad de la Capa de enlace deDatos detectar y corregir estos errores.

7/30/2019 Capa 1 2 3

21/63

Entramado o Enmarcado deDatos

7/30/2019 Capa 1 2 3

22/63

Es un concepto terico, que ayuda a entender la tec-nologa y las tramas (802.3, 802.5, FDDI), lospaquetes (IP) y los segmentos (TCP y UDP)especficos.

Tiene secciones llamadas campos formados por bytes campo de inicio de trama

campos de direccin campo de longitud/tipo/control campo de datos campo de secuencia de verificacin de trama

campo de fin de trama

Formato de Trama Genrica

7/30/2019 Capa 1 2 3

23/63

Tecnologas de la Capa 2

7/30/2019 Capa 1 2 3

24/63

802.0 SEC

802.1 High Level Interface (HILI)

802.2 Logical Link Control (LLC)

802.3 CSMA/CD Working Group

802.4 Token Bus

802.5 Token Ring

802.6 Metropolitan Area Network (MAN)

802.7 BroadBand Technical Adv. Group (BBTAG)

802.8 Fiber Optics Technical Adv. Group (FOTAG)

802.9 Integrated Services LAN (ISLAN)

802.10 Standard for Interoperable LAN Security (SILS)

802.11 Wireless LAN (WLAN)

802.12 Demand Priority

802.14 Cable-TV Based Broadband Communication Network

802.15 Wireless Personal Area Network (WPAN)

802.16 Broadband Wireless Access (BBWA)

RPRSG Resilient Packet Ring Study Group (RPRSG)

IEEE 802 Committees

IEEE 802.3 - 10 Mbps

IEEE 802.3u - 100 Mbps

IEEE 802.3z - 1000 Mbps

IEEE 802.3ab - 1000 Mbps

IEEE 802.11

IEEE 802.11a

IEEE 802.11b WiFi

IEEE 802.11g

IEE 802.11 n

7/30/2019 Capa 1 2 3

25/63

LAN: Ethernet

7/30/2019 Capa 1 2 3

26/63

Tipos de Ethernet

7/30/2019 Capa 1 2 3

27/63

Tipos de Ethernet

7/30/2019 Capa 1 2 3

28/63

Frames Ethernet

7/30/2019 Capa 1 2 3

29/63

Frames Ethernet 802.3 con 802.2

DSAP (Destination Service Access Point) y SSAP (Source Service Access

Point)

Service Access Point
http://es.wikipedia.org/w/index.php?title=Service_Access_Point&action=edit&redlink=1http://es.wikipedia.org/w/index.php?title=Service_Access_Point&action=edit&redlink=1

7/30/2019 Capa 1 2 3

30/63

100-Mbps Ethernet

100-Mbps Ethernet is also known as Fast Ethernet

100BASE-TX is copper UTP

100BASE-FX is multimode optical fiber

Frame format

100-Mbps frame format is the same as the 10-Mbps frame

Parts of the transmission process

Two separate encoding steps are used

The first part of the encoding uses a technique called

4B/5B

The second part of the encoding is the actual line

encoding specific to copper or fiber

7/30/2019 Capa 1 2 3

31/63

4B/5B Cada 4 bits de datos se codifica en

cdigos de 5-bit los cdigos de 5 bits son seleccionados

para tener no mas de un 0 inicial y no masde dos 0s finales. As, nunca se tienen mas de tres 0s

consecutivos

La palabra de cdigo de 5 bit sontransmitidas usando NRZI Se logra 80% de eficiencia

7/30/2019 Capa 1 2 3

32/63

1000-Mbps Ethernet

1000-Mbps Ethernet or Gigabit EthernetTransmission

Fiber and copper media

The 1000BASE-X IEEE 802.3z

Specifies 1 Gbps full duplex over optical fiber

1000BASE-TX, 1000BASE-SX, and 1000BASE-LX

Frame Format Same format used for 10 and 100-Mbps Ethernet

7/30/2019 Capa 1 2 3

33/63

1000-Mbps Ethernet

1000BASE-T (IEEE 802.3ab) was developed toprovide additional bandwidth for:

Intra-building backbones

Inter-switch links

Server farms Connections for high-end workstations

Supports both half-duplex and full-duplex

Fiber-based Gigabit Ethernet (1000BASE-X)

Uses 8B/10B encoding (similar to 4B/5B)

Uses encoding ZRZI Non Return to Zero Invertive

7/30/2019 Capa 1 2 3

34/63

7/30/2019 Capa 1 2 3

35/63

1000Base-LX/SX

NRZ signals are pulsed into the fiber Short-wavelength (1000BASE-SX ) Long-wavelength (1000BASE-LX)

Separate fibers

Transmitting (Tx)

Receiving (Rx)

Inherently full duplex

Gigabit Ethernet is the dominant technology for: Backbone installations

High-speed cross-connects

General infrastructure

7/30/2019 Capa 1 2 3

36/63

10 GigabitEthernet

10GBASE-SR Short distances, supports a range between 26 m to 82 m 10GBASE-LX4

Uses wide wavelength division multiplexing (WWDM)

240 m tHo 300 m over multimode fiber

10 km over single-mode fiber 10GBASE-LR and 10GBASE-ER

Support 10 km and 40 km over single-mode fiber 10GBASE-SW, 10GBASE-LW, and 10GBASE-EW

Known collectively as 10GBASE-W

7/30/2019 Capa 1 2 3

37/63

Future of EthernetFuture of Ethernet

The future of networking media is three-fold:1.Copper (up to 10-1000 Mbps, perhaps

more)

2.Wireless (approaching 1000 Mbps, perhaps

more)3.Optical fiber (currently at 10,000 Mbps and

soon to be more)

Copper and wireless media have certainphysical and practical limitations

7/30/2019 Capa 1 2 3

38/63

Ejercicios Extra-clase de anlisis de trficoutilizando la herramienta Wireshark

IP, ETHERNET, UDP, TCP, ARP, http, https

7/30/2019 Capa 1 2 3

39/63

Dispositivos de Capa 2

7/30/2019 Capa 1 2 3

40/63

Prove el puerto para la conexin dered

NICs

7/30/2019 Capa 1 2 3

41/63

Factores de Seleccin de la

NIC Al elegir la NIC se debe tener encuenta:

tipo de red Ethernet (10/100/1000 Mbps)

tipo de medios UTP, F.O., Wireless

tipo de bus del sistema

PCI, PCMCIA, USB

7/30/2019 Capa 1 2 3

42/63

PUENTES (BRIDGE) Dispositivo de capa 2 conecta

dos segmentos de LAN Trabajan a nivel de software

generando latencia Filtrar el trfico de una LAN

Verifica la direccin de cadadispositivo de la LAN

Crea una lista de MAC paratoma de decisiones

Cada NIC tiene una direccinMAC exclusiva El puente conecta solamente

dos segmentos a la vez Los routers y los switches han

desplazado al puente

7/30/2019 Capa 1 2 3

43/63

SWITCH

Dispositivo de la capa 2 Puente multipuerto

Toman decisiones basadosen las direcciones MAC

LANs mucho ms eficiente

7/30/2019 Capa 1 2 3

44/63

Segmenta una red endominios de colisin tantoscomo puertos activos posea

Conmutan" datos slodesde el puerto de origen alde destino

Suministra a cada puerto elancho de banda total

SWITCH

7/30/2019 Capa 1 2 3

45/63

Trabaja conmutando tramas de datos Aprende direcciones, reenviar, filtrar paquetes y

evitar bucles Controlar el trficos de mltiples segmentos

7/30/2019 Capa 1 2 3

46/63

7/30/2019 Capa 1 2 3

47/63

Layer 2 and layer 3 switching

A layer 3 switch is typically a layer 2 switch that includes arouting process

Layer 3 switching has many meanings and in many cases isjust a marketing term.

Layer 3 switching is a function of the network layer. The Layer 3 header information is examined and the packet is

forwarded based on the IP address.

Symmetric and asymmetric

7/30/2019 Capa 1 2 3

48/63

Symmetric and asymmetricswitching

7/30/2019 Capa 1 2 3

49/63

Tres mtodos de conmutacin

Store-and-forward The entire frame is receivedbefore any forwarding takes place. The destination and source addresses are read and

filters are applied before the frame is forwarded. CRC (count of redundancy cyclical)| Check done is

forwarded Cut-through The frame is forwarded through the

switch before the entire frame is received. This mode decreases the latency of the

transmission, but also reduces error detection.

7/30/2019 Capa 1 2 3

50/63

Free of fragmenteste es una modificacion de metodo de corte, elswitch lee los primeros 64 bytes antes de transmitir la trama.

7/30/2019 Capa 1 2 3

51/63

Dominios de Broadcast Todos los hosts conectados al mismo

switch permanecen en el mismodominio de broadcast

Un broadcast desde un nodo ser vistopor todos los otros nodos conectadosen el mismo switch

7/30/2019 Capa 1 2 3

52/63

Dominios de Broadcast Todos los hosts conectados al mismo

switch permanecen en el mismodominio de broadcast

Un broadcast desde un nodo ser vistopor todos los otros nodos conectadosen el mismo switch

7/30/2019 Capa 1 2 3

53/63

APRENDIZAJE DE DIRECCIONES

Un switch crea circuitos Virtuales entresegmentos identificando lasdirecciones MAC de destino asociada

a un puerto Cuando un switch se inicia no posee

datos MAC por lo que inunda todos los

puertos para obtener la MAC

7/30/2019 Capa 1 2 3

54/63

Segmentacin con Routers

7/30/2019 Capa 1 2 3

55/63

Tarea Extra-Clase:Realizar un cuadro comparativo de

caractersticas tcnicas & estndares de 3

switches de diferentes fabricantes (Cisco,Enterasys, HP, D-link, TPLINK,

TRENDNET, ETC...).

7/30/2019 Capa 1 2 3

56/63

Capa de RedEnrutamiento y Direccionamiento

7/30/2019 Capa 1 2 3

57/63

Importancia de la Capa de

Red Identificacin

Segmentacin Comunicacin entre redes Determinacin de Ruta

Direccionamiento

7/30/2019 Capa 1 2 3

58/63

Airport

School

Gas Station

Hospital

Factory

Train Station

FD

Fire Department

Stadium

Sidew

City Str

Intersta

7/30/2019 Capa 1 2 3

59/63

Airport

School

Gas Station

Hospital

Factory

Train Station

FD

Fire Department

Stadium

Sidewalk

City Street

Interstate

Bomberos a la Escuela

7/30/2019 Capa 1 2 3

60/63

F

C

G

E

B

DA

Internet

56

T1 1.5Mbps

T3 45Mbps

A

D

7/30/2019 Capa 1 2 3

61/63

F

C

G

E

B

DA

Internet

56

T1 1.5Mbps

T3 45Mbps

Red C a Red G

B

C

D

E

FG

Direccionamiento (Capa de

7/30/2019 Capa 1 2 3

62/63

Direccionamiento (Capa deRed)

7/30/2019 Capa 1 2 3

63/63

Capa de Red

Direcciones IP dentro del

Encabezado IP

Documents

Capa 1 2 3