Tema 2: Tecnologías LAN. - UPV LAN.pdf · Tema 2: Tecnologías LAN. Evolución de Ethernet. ... EoMPLS VPLS EoRPR NG-SONET ... provide Multipoint Ethernet services

Tema 2: Tecnologías LAN.Tema 2: Tecnologías LAN.

� Evolución de Ethernet.� Ethernet para MANs

� VPLS

� EtherChannelResilient Ethernet: HSRP

TECNOLOGÍAS DE RED AVANZADAS – Master IC 2009-2010 – http://www.grc.upv.es/docencia/tra/

� Resilient Ethernet: HSRP

TECNOLOGÍAS DE RED AVANZADAS –MasterIC 2009-2010

Overview

� Ethernet is the dominant LAN technology. � Easy to implement; flexible.

� 10BASE5, 10BASE2, & 10BASE-T Ethernet � Manchester encoding � Ethernet timing limits � 10BASE-T wiring parameters

� 100-Mbps Ethernet (Fast Ethernet)

TECNOLOGÍAS DE RED AVANZADAS

� 100-Mbps Ethernet (Fast Ethernet)�Gigabit Ethernet

� MAC, frame formats, & transmission process� media and encoding� pinouts and wiring

�Gigabit and 10-Gigabit Ethernet

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TECNOLOGÍAS DE RED AVANZADAS –MasterIC 2009-201010 Mbps Ethernet

� 4 common features of Legacy Ethernet:� timing parameters, frame format, transmission processes, & basic design rule.

�Asynchronous� Uses Preamble and SFD for synchronization

� Slot Time� For speeds ≤1000 Mbps, minimum transmission time


� For speeds ≤1000 Mbps, minimum transmission time

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10BaseT

� Introduced in 1990� UTP cheaper & easier to install than co-ax.� Star or extended star topology.

� Supports half- & full-duplex.� 10 Mbps at half-duplex; 20 Mbps at full-duplex.

�Manchester encoding�Max unrepeated distance 100m


�Max unrepeated distance 100m�UTP Categories:

� 3 - 16 Mhz, 100 ohms � 4 – 20 Mhz, 100 ohms� 5 – 100 Mhz , 100 ohms� 5e – 350 Mhz, 100 ohms

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10BaseT Wiring & Architecture

� Star topology� Hub or switch as concentration point.

� Switch divides into separate collision domains.

� Design concern – minimize delay between distant stations.


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100 Mbps or Fast Ethernet

�Two technologies:� 100Base-TX : copper UTP� 100Base-FX : multimode optical fiber

� Same frame format as 10 Mbps Ethernet� 10x faster than 10Base-T

� Timing is more critical; � more susceptible to noise.


� more susceptible to noise.� Uses two encoding steps

� 4B/5B� Actual line encoding.

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1000 Mbps or Gigabit Ethernet

� Standards� IEEE 802.3ab – Gigabit using Cat 5, or higher.� IEEE 802.3z - Gigabit over optical fiber.

� 1000Base-TX, 1000Base-SX, & 1000Base-LX use same timing, transmission, & frame format.

�Uses two separate encoding steps:� At physical layer, bit patterns from the MAC layer are converted


� At physical layer, bit patterns from the MAC layer are converted into symbols.

� frame is coded into control & data symbols to increase in network throughput.

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1000Base-T

� Designed for Cat 5e or better UTP.� uses all four pairs of wires; full-duplex transmissions on each wire pair! - 250 Mbps per pair; 1000 Mbps for 4 wire pairs.

� Data is divided into 4 parallel streams, encoded, transmitted,


streams, encoded, transmitted, detected, and reassembled.

� Supports both half and full duplex.� Full-duplex is widespread.

� 4D-PAM5 – Pulse Amplitude Modulation

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1000Base-SX and LX

� IEEE 802.3 standard recommended preferred backbone technology� Timing, frame format, & transmission are common to all versions of 1000 Mbps.

� Uses 8B/10B encoding; and NRZ line encoding.


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1000Base-SX and LX (2)

� SX vs LX� SX is short-wavelength

� 850 nm; multimode.

� LX is long-wavelength� 1310 nm; single or multimode.

�MAC method treats link


�MAC method treats link as point-to-point.� Separate fibers for Tx and Rx.

� Inherently full duplex.

�Gigabit Ethernet permits only a single repeater between two stations.

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Gigabit Ethernet Architecture

�Distance limitations of full-duplex links� limited only by the medium; not round-trip delay.

�Auto-Negotiation recommended for all links between station & hub or switch.� to permit highest common performance.


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10 Gigabit Ethernet

� IEEE 802.3ae standard (2002).� 10 Gbps full-duplex transmission over fiber.� Use in LANs, MANs, WANs.

� distance to 40 km over single-mode fiber.� compatibility with SONET and SDH networks.

� Properties� Same Frame format


� Same Frame format� Compatible with legacy, fast, & gigabit, with no reframing or protocol conversions.

� Bit time is 0.1 nanoseconds. � Full-duplex only (CSMA/CD not necessary). � IEEE 802.3 sublayers within OSI Layer 2 are preserved.

� Some additions to accommodate 40 km fiber links and interoperability with SONET/SDH technologies.

� Flexible, efficient, reliable, relatively low cost end-to-end Ethernet networks become possible.

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10 Gigabit Ethernet (3)

� Implementations being considered: � 10GBASE-SR

� for short distances (26 – 82 m) over multimode fiber.

� 10GBASE-LX4 � distances 240 m to 300 m over multimode fiber, and 10 km over single-mode fiber.

� 10GBASE-LR & 10GBASE-ER


� 10 km & 40 km over single-mode fiber.

� 10GBASE-SW, 10GBASE-LW, & 10GBASE-EW � to work with OC-192 synchronous transport module SONET/SDH WAN equipment.

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10 Gigabit Ethernet Architecture

� Issues of synchronization, bandwidth, and Signal-to-Noise Ratio:� 10-Gigabit Ethernet uses two encoding steps.

� uses codes (symbols) for user data give efficient transmission.� encoded data provides synchronization, efficient use of BW, and improved Signal-to-Noise


and improved Signal-to-Noise Ratio.

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Future of Ethernet

� Ethernet is evolving into LAN, MAN, & WAN technology.� Standards for 40, 100, or even 160 Gbps are being developed.

� Full-duplex high-speed Ethernet technologies are taking over even QoS-intensive applications.� Like: IP telephony & video multicast.


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Evolución de Ethernet

Acceso Distribución Metro Metro Core

ATMSONET/SDH

ATMSONET/SDH

ATM ADSLT1/E1

FRATM

GlobalInternet

Casa

MDU

Resid

en

cia

l


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Optical EthernetEoMPLS

VPLSEoRPR

NG-SONET(EoS)Metro DWDM

Optical EthernetEoMPLS

VPLSRPR

NG-SONET(EoS)Metro DWDM

IP ADSLIP VDSLEPONEFM

Optical EthernetEoRPR

NG-SONET(EoS)

GlobalInternet

STU

MTU

Em

pre

sa


Servicios Metropolitanos

�Algunos servicios son:� Conectividad Internet � Transparent LAN service (punto a punto LAN to LAN)� L2VPN (punto a punto o multipunto a multipunto LAN to LAN)� Extranet� LAN a Frame Relay/ATM VPN� Conectividad a centro de backup


� Conectividad a centro de backup� Storage area networks (SANs)� Metro transport (backhaul)� VoIP

�Algunos se están ofreciendo desde hace años. La diferencia está en que ahora se ofrecen usandoconectividad Ethernet !!

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Servicio Ethernet – Modelo de referencia

�Customer Equipment (CE) se conecta a través de UNI

�CE puede ser un � router� Bridge IEEE 802.1Q (switch)

�UNI (User Network Interface)� Standard IEEE 802.3 Ethernet PHY and

CEUNI


� Standard IEEE 802.3 Ethernet PHY and MAC

� 10Mbps, 100Mbps, 1Gbps or 10Gbps� Soporte de varias clases de servicio (QoS)

�Metro Ethernet Network (MEN)� Puede usar distintas tecnologías de transporte y de provisión de servicio� SONET/SDH, WDM, PON, RPR, MAC-in-MAC, QiQ (VLAN stack), MPLS

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CE

CE

Metro Metro Ethernet Ethernet Network Network (MEN)(MEN)

UNI


Servicio Ethernet – Modelo (2)

� Sobre el anterior modelo, se añade un cuarto ingrediente: una Ethernet Virtual Connection (EVC)

� EVC: es una asociación entre dos o más UNI� Es creada por el proveedor del servicio para un cliente� Una trama enviada en un EVC puede ser enviada a uno o másUNIs del EVC:�Nunca será enviada de vuelta al UNI de entrada.


�Nunca será enviada de vuelta al UNI de entrada.�Nunca será enviada a un UNI que no pertenezca al EVC.

� Las EVC´s pueden ser:� Punto a punto (E-Line)� Multipunto a multipunto (E-LAN)

�Cada tipo de servicio ethernet tiene un conjunto de atributos de servicio y sus correspondientes parámetros que definen las capacidades del servicio.

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Atributos de un servicio en particular Ethernet

�Multiplexación de servicios� Asocia una UNI con varias EVC. Puede ser:

�Hay varios clientes en una sóla puerta (ej. En un POP UNI)�Hay varias conexiones de servicios distintos para un solo cliente

�Transparencia de VLAN� Significa que proveedor del servico no cambia el identificador de la VLAN ( el MEN aparece como un gran switch)


la VLAN ( el MEN aparece como un gran switch)� En el servicio de acceso a Internet tiene poco importancia

� “Bundling”� Más de una VLAN de cliente está asociada al EVC en una UNI

� Etc.

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Atributos

�Atributos de UNI: � identificador, tipo de medio, velocidad, duplex, etc� Atributo de soporte de VLAN tag� Atributo de multiplexación de servicio� Security filters attribute� etc

�Atributos de EVC:


�Atributos de EVC:� Parámetros de tráfico (CIR, EIR, in, out, etc)

� Committed Information Rate (CIR) � Excess Information Rate (EIR)

� Parámetros de prestaciones (delay, jitter, etc)� Parámetros de Clase de Servicio (VLAN-ID, valor de .1p, etc)� Multicast frame delivery� etc

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Servicio Ethernet Line (E-Line)

UNI

Point-to-Point Ethernet Virtual Circuits

(EVC)

IP PBX

Servers

IP Voice


2

2

Data

CE

CE

CE

Metro Ethernet Network

1 or more UNIs

UNI

Video

IP PBX

Data

IP Voice


Servicio Ethernet Line (E-Line)

�Una E-Line puede operar con ancho de banda dedicado ó con un ancho de banda compartido.

�EPL: Ethernet Private Line� Es un servicio EVC punto a punto con un ancho de banda dedicado

� El cliente siempre dispone del CIRNormalmente en canales SDH ó en redes MPLS


� Normalmente en canales SDH ó en redes MPLS� Es como una línea en TDM, pero con una interfaz ethernet

�EVPL: Ethernet Virtual Private Line� En este caso hay un CIR y un EIR y una métrica para el soporte de SLAs (service level agreement)

� Es similar al Frame Relay� Se suele implementar con canales TDM compartidos ó con redes de conmutación de paquetes usando SW´s y/o routers

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Servicio Ethernet LAN (E-LAN)

Multipoint-to-Multipoint Ethernet Virtual Circuit

(EVC)

UNI

UNI

ServersIP Voice


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CE

CE

CE

Metro Ethernet Network

CE

UNIUNI

IP PBX

Data

Data

Data

IP Voice

IP Voice


Servicio Ethernet LAN (E-LAN)

�Una E-LAN puede operar con ancho de banda dedicado ó con un ancho de banda compartido.

� EPLan: Ethernet Private LAN� Suministra una conectividad multipunto entre dos o más UNI´s, con un ancho de banda dedicado.

� EVPLan: Ethernet Virtual Private LAN� Otros nombres:


� Otros nombres:� VPLS: Virtual Private Lan Service� TLS: Transparent Lan Service� VPSN: Virtual Private Switched Network

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TECNOLOGÍAS DE RED AVANZADAS –MasterIC 2009-2010Un ejemplo: ONO


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TECNOLOGÍAS DE RED AVANZADAS –MasterIC 2009-2010Un ejemplo: ONO


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Otro ejemplo: TelefonicaTECNOLOGÍAS DE RED AVANZADAS

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Otro ejemplo: TelefonicaTECNOLOGÍAS DE RED AVANZADAS

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Virtual Private LAN Service (VPLS)

�VPLS defines an architecture allows MPLS networks offer Layer 2 multipoint Ethernet Services

� SP emulates an IEEE Ethernet bridge network (virtual)�Virtual Bridges linked with MPLS Pseudo Wires

� Data Plane used is same as EoMPLS (point-to-point)


PE PECE CE

VPLS is an Architecture

CE


Virtual Private LAN Service

� End-to-end architecture that allows MPLS networks to provide Multipoint Ethernet services

� It is “Virtual” because multiple instances of this service share the same physical infrastructure

� It is “Private” because each instance of the service is


� It is “Private” because each instance of the service is independent and isolated from one another

� It is “LAN Service” because it emulates Layer 2 multipoint connectivity between subscribers


Why Provide A Layer 2 Service?

�Customer have full operational control over their routing neighbours

� Privacy of addressing space - they do not have to be shared with the carrier network

�Customer has a choice of using any routing protocol


�Customer has a choice of using any routing protocolincluding non IP based (IPX, AppleTalk)

�Customers could use an Ethernet switch instead of a router as the CPE

�A single connection could reach all other edge points emulating an Ethernet LAN (VPLS)


VPLS is defined in IETF

Application

GeneralFormerly PPVP�

workgroup

VPWS, VPLS, IPLS

BGP/MPLS VP�s (RFC

4364 was 2547bis)

IAB

ISOC

Internet

L2VP�

L3VP�


Ops and Mgmt

Routing

Security

IETF

MPLS

Transport

4364 was 2547bis)

IP VP�s using Virtual

Routers (RFC 2764)

CE based VP�s using IPsec

Pseudo Wire Emulation

edge-to-edge

Forms the backbone

transport for VPLS

As of 2-�ov-2006

PWE3


Classification of VPNs

CPE

Based

�etwork

Based

VP�


Layer 3

MPLS

VP�

Virtual

Router

GREIPSec

Layer 3

P2P VPWSEthernet

Frame Relay

PPP/HDLC

ATM/Cell R

elay

Ethernet (P

2P)

Frame Relay

ATM

Ethernet (P

2MP)

Ethernet (M

P2MP)

Layer 2

VPLS

IPLS


L2VPN Models

IP

Like-to-LikeLike-to-Like

L2VP�

MPLS


ATM

AAL5/Cell

PPP

HDLC

Ethernet FR

L2TPv3

Point-to-Point

ATM

AAL5/Cell

PPP

HDLC

Ethernet FR

VPWS

Point-to-Point

Like-to-Like

Any-to-Any

Like-to-Like

Any-to-AnyLike-to-LikeLike-to-Like

VPLS/IPLS

Multipoint

Ethernet


IP LAN-Like Service (IPLS)

�An IPLS is very similar to a VPLS except� The CE devices must be hosts or routers not switches� The service will only carry IPv4 or IPv6 packets � IP Control packets are also supported – ARP, ICMP� Layer 2 packets that do not contain IP are not supported

� IPLS is a functional subset of the VPLS service


� IPLS is a functional subset of the VPLS service� MAC address learning and aging not required� Simpler mechanism to match MAC to CE can be used� Bridging operations removed from the PE� Simplifies hardware capabilities and operation

�Defined in draft-ietf-l2vpn-ipls


VPLS Components

�-PECE router

CE router

CE router

CE router

Attachment circuits

Port or VLA� modeMesh of LSP between �-PEs

�-PE

Pseudo Wires within LSPVirtual Switch Interface (VSI)

terminates PW and provides

Ethernet bridge function


MPLS

Core

CE router

CE switch

CE router

CE switch

CE switch

CE router

�-PE

Targeted LDP between PEs to

exchange VC labels for Pseudo Wires Attachment CE

can be a switch or router

Tema 2: Tecnologías LAN.Tema 2: Tecnologías LAN.

�EtherChannel�Resilient Ethernet: HSRP

TECNOLOGÍAS DE RED AVANZADAS – Master IC 2009-2010 – http://www.grc.upv.es/docencia/tra/


Etherchannel Concepts

An Etherchannel combines multiple physical links into a single logical link. Ideal for load

sharing or link redundancy – can be used by both layer 2 and Layer 3 subsystems…

Physical ViewMultiple ports are

defined as being

part of an

Etherchannel


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9

group

Logical ViewSubsystems running

on the switch only

see one logical link

An Etherchannel can be defined on Ethernet, Fast Ethernet, Gigabit Ethernet or 10 Gigabit

Ethernet Ports

TECNOLOGÍAS DE RED AVANZADAS –MasterIC 2009-2010 Etherchannel Concepts

Multichassis EtherChannel (MEC)

Prior to Virtual Switch, Etherchannels were restricted to reside within the same physical

switch. In a Virtual Switch environment, the 2 physical switches form a single logical network

entity - therefore Etherchannels can now also be extended across the 2 physical chassis…

Virtual Switch Virtual Switch


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0

Regular Etherchannel on single chassis Multichassis EtherChannel across 2 VSL-

enabled Chassis


Resilient Ethernet

�How does a workstation get a default gateway?� DHCP: gives the workstation the default gateway� IRDP (ICMP Router Discovery Protocol): extension to ICMP that allows an end-station to automatically discover a default gateway. RPs (Route Processors) periodically generate special multicast packets that announce the router’s existence to the clients every 5 to 10 minutes. Multicast packet has the RP’s address and a life-time value. Could take up to 30 minutes.


address and a life-time value. Could take up to 30 minutes.� Proxy ARP: host dynamically discovers default IP address and MAC of the default gateway. When default gateway fails, traffic is dropped. After a lengthy period of time, host will re-perform the Proxy ARP, but in most situations, host will continue using same failed default gateway.

�What happens to the workstation when router fails?� Host can’t communicate with other networks

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Solution is HSRP (Hot Standby Routing Protocol)

�Cisco-proprietaryprotocol

�Provides Layer 3redundancy

�Transparent to end stations


stations�RP (Route Processor) monitors the status of other RPs and provides a quick failover when primary default gateway fails.4

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HSRPTECNOLOGÍAS DE RED AVANZADAS

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HSRPTECNOLOGÍAS DE RED AVANZADAS

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HSRP Group

�A group of 2 or more RPs that represent a single default gateway. It has a virtual IP address and a virtual MAC address. If the primary RP fails, another RP takes over.


another RP takes over.�One RP can be the backup for multiple primary default gateways

�Only one RP forwards data for a LAN.

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HSRP Group

�Group has the following type of RPs:�Virtual RP�Active RP�Standby RP�Other RPs

�Virtual RP


�Virtual RP� Provides a single RP that is available to end stations.

� Not a real RP—the IP and MAC addresses are not physically assigned to any one interface on any of the RPs in the broadcast domain4

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HSRP Group

� Active RP� Responsible for forwarding all traffic destined for the Virtual RPs MAC address.

� Elected in an election process—RP with highest priority is active. If priorities are same, highest IP address wins. Default priority is 100.

� Only one active RP per network/subnetwork/VLAN

� Standby RP� Elected in an election process


� Elected in an election process� Keeps tabs on Active RP by looking for HSRP multicast messages (HSRP hellos). Hellos are sent by active RP every 3 seconds. If standby doesn’t hear any hellos for 10 seconds, it promotes itself and becomes the active RP.

� Sends out its own hellos every 3 seconds so that if it fails, one of the other possible HSRP RPs in the standby group will become the standby.

� Only one standby RP per network/subnetwork/VLAN

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HSRP Group

�Other HSRP RPs� Listen for hellos from standby and active RPs. � If any end-station uses a REAL MAC address of one of the RPs in the broadcast domain, that specific RP (whether active, standby or other RP) will process and forward the frame.

� Each standby group must have a unique virtual IP address and a virtual MAC address.


address and a virtual MAC address.� These addresses are unique across different VLANs.

� End stations perform an ARP request with the virtual IP address and get the virtual MAC address of the default gateway RP.

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Documents

Tema 2: Tecnologías LAN. - UPV LAN.pdf · Tema 2: Tecnologías LAN. Evolución de Ethernet. ... EoMPLS VPLS EoRPR NG-SONET ... provide Multipoint Ethernet services