tema 1: tecnologías de red

Transmisión de Datos Multimedia – http://www.grc.upv.es/docencia/tdm – Master IC 2007/2008

Tema 1: Tecnologías de red.

Estructura de InternetRedes “core”

SONET DWDM

Redes de acceso Redes cableadas: Ethernet et al. Redes inalámbricas: IEEE 802.11, UMTS et al.

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What’s the Internet: “nuts and bolts” view End systems

Host computerNetwork applications

Access networksLocal area networkscommunication links

Network core: routersnetwork of networks

local ISP

companynetwork

regional ISP

router workstationserver mobile

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Internet structure: network of networks

roughly hierarchical at center: “tier-1” ISPs (e.g., MCI, Sprint, AT&T, Cable and

Wireless), national/international coverage treat each other as equals

Tier 1 ISP

Tier 1 ISP

Tier 1 ISP

Tier-1 providers interconnect (peer) privately

NAP

Tier-1 providers also interconnect at public network access points (NAPs)

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Tier-1 ISP: e.g., Sprint

Sprint US backbone network

Seattle

Atlanta

Chicago

Roachdale

Stockton

San Jose

Anaheim

Fort Worth

Orlando

Kansas City

CheyenneNew York

PennsaukenRelay

Wash. DC

Tacoma

DS3 (45 Mbps)OC3 (155 Mbps)OC12 (622 Mbps)OC48 (2.4 Gbps)

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“Tier-2” ISPs: smaller (often regional) ISPs Connect to one or more tier-1 ISPs, possibly other tier-2 ISPs

Tier 1 ISP

Tier 1 ISP

Tier 1 ISP

NAP

Tier-2 ISPTier-2 ISP

Tier-2 ISP Tier-2 ISPTier-2 ISP

Tier-2 ISP pays tier-1 ISP for connectivity to rest of Internet tier-2 ISP is customer oftier-1 provider

Tier-2 ISPs also peer privately with each other, interconnect at NAP

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“Tier-3” ISPs and local ISPs last hop (“access”) network (closest to end systems)

Tier 1 ISP

Tier 1 ISP

Tier 1 ISP

NAP



localISPlocal

ISPlocalISP

localISP

localISP Tier 3

ISP

localISP

localISP

localISP

Local and tier- 3 ISPs are customers ofhigher tier ISPsconnecting them to rest of Internet

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a packet passes through many networks!

Tier 1 ISP

Tier 1 ISP

Tier 1 ISP

NAP



localISPlocal

ISPlocalISP

localISP

localISP Tier 3

ISP

localISP

localISP

localISP

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Network Access Points (NAPs)

Source: Boardwatch.com

Note: Peers in this context are commercial backbones..droh

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9Source: www.lightreading.com

MCI/WorldCom/UUNET Global Backbone

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The situation in Europe

See: http://www.geant2.net/server/show/nav.1368

http://www.geant2.net/server/show/nav.1368








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Standards

Mandatory vs. voluntary Allowed to use vs. likely to sell Example: health & safety standards UL listing for electrical

appliances, fire codes Telecommunications and networking always focus of

standardization 1865: International Telegraph Union (ITU) 1956: International Telephone and Telegraph Consultative

Committee (CCITT) Five major organizations:

ITU for lower layers, multimedia collaboration IEEE for LAN standards (802.x) IETF for network, transport & some applications W3C for web-related technology (XML, SOAP) ISO for media content (MPEG)

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Who makes the rules? - ITU

ITU = ITU-T (telecom standardization) + ITU-R (radio) + development http://www.itu.int 14 study groups produce Recommendations:

E: overall network operation, telephone service (E.164) G: transmission system and media, digital systems and networks

(G.711) H: audiovisual and multimedia systems (H.323) I: integrated services digital network (I.210); includes ATM V: data communications over the telephone network (V.24) X: Data networks and open system communications Y: Global information infrastructure and internet protocol aspects

http://www.itu.int/

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ITU

Initially, national delegations Members: state, sector, associate

Membership fees (> 10,500 SFr) Now, mostly industry groups doing work Initially, mostly (international) telephone services Now, transition from circuit-switched to packet-switched

universe & lower network layers (optical) Documents cost SFr, but can get three freebies for each

email address

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IETF

IETF (Internet Engineering Task Force) see RFC 3233 (“Defining the IETF”)

Formed 1986, but earlier predecessor organizations (1979-) RFCs date back to 1969 Initially, largely research organizations and universities,

now mostly R&D labs of equipment vendors and ISPs International, but 2/3 United States

meetings every four months about 300 companies participating in meetings

but Cisco, Ericsson, Lucent, Nokia, etc. send large delegations

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IETF

Supposed to be engineering, i.e., translation of well-understood technology standards make choices, ensure interoperability reality: often not so well defined

Most development work gets done in working groups (WGs) specific task, then dissolved (but may last 10 years…) typically, small clusters of authors, with large peanut gallery open mailing list discussion for specific problems interim meetings (1-2 days) and IETF meetings (few hours) published as Internet Drafts (I-Ds)

anybody can publish draft-somebody-my-new-protocol also official working group documents (draft-ietf-wg-*) versioned (e.g., draft-ietf-avt-rtp-10.txt) automatically disappear (expire) after 6 months

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IETF process

WG develops WG last call IETF last call approval (or not) by IESG publication as RFC

IESG (Internet Engineering Steering Group) consists of area directors – they vote on proposals areas = applications, general, Internet, operations and

management, routing, security, sub-IP, transport Also, Internet Architecture Board (IAB)

provides architectural guidance approves new working groups process appeals

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IETF activities general (3): ipr, nomcom, problem applications (25): crisp, geopriv, impp, ldapbis, lemonade,

opes, provreg, simple, tn3270e, usefor, vpim, webdav, xmpp

internet (18) = IPv4, IPv6, DNS, DHCP: dhc, dnsext, ipoib, itrace, mip4, nemo, pana, zeroconf

oam (22) = SNMP, RADIUS, DIAMETER: aaa, v6ops, netconf, …

routing (13): forces, ospf, ssm, udlr, … security (18): idwg, ipsec, openpgp, sasl, smime, syslog, tls,

xmldsig, … subip (5) = “layer 2.5”: ccamp, ipo, mpls, tewg transport (26): avt (RTP), dccp, enum, ieprep, iptel,

megaco, mmusic (RTSP), nsis, rohc, sip, sipping (SIP), spirits, tsvwg

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RFCs

Originally, “Request for Comment” now, mostly standards documents that are well settled published RFCs never change always ASCII (plain text), sometimes PostScript anybody can submit RFC, but may be delayed by review

(“end run avoidance”) see April 1 RFCs (RFC 1149, 3251, 3252) accessible at http://www.ietf.org/rfc/ and http://www.rfc-

editor.org/

http://www.ietf.org/rfc/

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IETF process issues

Can take several years to publish a standard see draft-ietf-problem-issue-statement

Relies on authors and editors to keep moving often, busy people with “day jobs” spurts three times a year

Lots of opportunities for small groups to delay things Original idea of RFC standards-track progression:

Proposed Standard (PS) = kind of works Draft Standard (DS) = solid, interoperability tested (2

interoperable implementations for each feature), but not necessarily widely used

Standard (S) = well tested, widely deployed

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IETF process issues

Reality: very few protocols progress beyond PS and some widely-used protocols are only I-Ds

In addition: Informational, Best Current Practice (BCP), Experimental, Historic

Early IETF: simple protocols, stand-alone TCP, HTTP, DNS, BGP, …

Now: systems of protocols, with security, management, configuration and scaling lots of dependencies wait for others to do their job

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Other Internet standards organizations

ISOC (Internet Society) legal umbrella for IETF, development work

IANA (Internet Assigned Numbers Authority) assigns protocol constants

NANOG (North American Network Operators Group) (http://www.nanog.org) operational issues holds nice workshop with measurement and “real world”

papers RIPE, ARIN, APNIC

regional IP address registries dole out chunks of address space to ISPs

routing table management

http://www.nanog.org/

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ICANN

Internet Corporation for Assigned Names and Numbers manages IP address space (at top level) DNS top-level domains (TLD)

ccTLD: country codes (.us, .uk, …) gTLDs (.com, .edu, .gov, .int, .mil, .net, and .org) uTLD (unsponsored): .biz, .info, .name, and .pro sTLD (sponsored): .aero, .coop, and .museum

actual domains handled by registrars




SONET DWDM


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IP and Traditional Transport

In the 80’s, software based routers were interconnected via relatively slow links 56K (early 80’s), to fractional T1, to full T1, to T3

This was layered over core TDM infrastructure Which was intended for voice and circuits

Generally, data folks ignored TDM folks, and vice versa

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Time Division Multiplexing

Multiplexed Bit Stream

Sum of sources = Total MUX’d bit stream

MUX TimeSlot1

TimeSlot2

TimeSlot4

TimeSlot3

TimeSlot6

TimeSlot1

TimeSlot5

TimeSlot2

SyncBit

SyncBit

Source 1

Source 2

Source 3

Source 4

Source 5

Source 6

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SONET & SDH

SONET - Synchronous Optical NETwork ANSI/Bellcore standard

SDH - Synchronous Digital Hierarchy ITU (European) standard

Both standards are practically identical Standards for a synchronous digital transmission system of

TDM traffic over fiber networks. Standards based system for data rates above a T3.

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SONET/SDH Hierarchy

STS - Synchronous Transport Signals 51.84Mbps - base level of SONET hierarchy

STM - Synchronous Transport Module 155.52Mbps - base level of SDH hierarchy Exactly equal to STS-3

STS OC STMBit Rate (Mbps)

STS-1 OC-1 51.84STS-3 OC-3 STM-1 155.52STS-12 OC-12 STM-4 622.08STS-48 OC-48 STM-16 2488.32STS-192 OC-192 STM-64 9953.28STS-768 OC-768 STM-256 39813.12

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STS/OC/STM

STS-n and OC-n are identical - OC-n names are used for optical interconnects STS-n names are used for electrical interconnects

OC-n is exactly n times the rate of an OC-1 signal. STM-1 signal is exactly 3 times the rate of an STS-1 signal STM-n is exactly n times the rate of an STM-1 signal

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ADM, Terminal, Repeater

SONET/SDH terminal - a mux/demux that creates a SONET signal and terminates paths.

SONET/SDH ADM (Add/Drop Multiplexer) - a mux/demux that can separate individual STS-n signals from a higher level signal.

SONET/SDH repeater- a physical level regenerator that also terminates section level overhead to allow section level management.

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SONET/SDH - Path/Section/Line

In Sonet/SDH systems a strong designation of levels of overhead are kept.

Section is lowest level Repeater to repeater

Line is middle layer Path is top/longest layer

from entrance to SONET system to exit of SONET system

Repeater

Add/DropMultiplexer

Add/DropMultiplexer

TerminalMultiplexer

TerminalMultiplexer

Repeater

Section Section Section Section Section

Line Line Line

Path

T3

T3

T3

T3

OC-n OC-n OC-n OC-n OC-n

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SONET/SDH - Section & Line Overhead

The section overhead is the first 3 rows of the first 3 columns (9 bytes) per frame.

The line overhead is the lower 6 rows of the first 3 columns (18 bytes) per frame.

An STS-1 frame consists of 810 bytes (octets) sent in 125µs. 810 * 8 * 8000 = 51.84Mbps

The 810 bytes are arranged as 90 columns x 9 rows 3 columns are overhead 87 columns are actual data

STS-1 Payload

87 columnsA1 A2 C1

B1 E1 F1

D1 D2 D3

H1 H2 H3

B2 K1 K2

D4 D5 D6

D7 D8 D9

D10 D11 D12

Z1 Z2 Z3

SectionOverhead

LineOverhead

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STS concatenated signals

Multiple STS-1s can be grouped together into a single higher bit rate facility.

Extra overhead bytes are ignored. Technically, any number of STS-1s can be grouped, but the

only groupings normally supported are: STS-3C, STS-12C, STS-48C

Generally a grouping must fall on a boundary of the same size inside of the OC-n carrier A STS-3C must fall on a boundary of 3 STS-12C must fall on a boundary of 12

Typically used for situations where ATM or Packets are sent over a SONET network.

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Traditional View of Routers and Links

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Terminal Multiplexer

SONET/SDHADM

SONET/SDHADM

SONET/SDHADM

SONET/SDHADM

SONET/SDHDCS

SONET/SDHDCS

SONET/SDHDCSTerminal

Multiplexer



Terminal Multiplexer Terminal

Multiplexer

SONET/SDHADM

SONET/SDHADM

Reality has always been more complex

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Optical Fiber Evolution

Fiber is better than copper wire Purity – low attenuation and distortion

Longer distances, lower bit error rates Higher frequency signals – massive bandwidth Different wavelengths – massive bandwidth Immunity to noise Security – difficult to tap Small size and weight

Easier installation Bundles of fibers in same space as copper wire

Multimode fiber Low cost – LEDs, not lasers Many wavelengths (modes) Dispersion – limits bandwidth and distance

Light pulses spread out Intramodal – different delay per mode Typically 2 km maximum distance

Large diameter cores – for multiple modes Initially flat profile Stepped end improves performance

Single-mode fiber One wavelength – small core Less interference and loss

Greater distance (up to 100 km) More expensive components – lasers Minimized dispersion point at 1310 nm

Not suitable for EDFA (Erbium Doped Fiber-optic Amplifier)

Non-zero dispersion shifted fiber Optimized for longer distances Optimized for higher bandwidth Minimized dispersion point shifted to 1550

nm Suitable for Erbium-based optical amplifiers Silica-based fibers have lowest attenuation at

1550 nm, not 1310

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SONET/SDH ADM SONET/SDH ADM

WDM Node WDM Node

From One Wavelength Per Fiber to Many

ADM

Single Fiber

SONET/SDH ADM

Single Fiber

Wave Division Multiplexing

OT = Optical Transponder

OT

ADM

ADM

ADM

ADM

ADM

ADM

ADM

OT

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WDM System Elements

SONET/SDH ADM

SONET/SDH ADM

SONET/SDH ADM

SONET/SDH ADM

SONET/SDH ADM

SONET/SDH ADM

= Regenerators

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TDM and WDM Relationship

1 … n

TDM generates output from sum of inputs into a single

bit stream

Laser Output

nn

1

WDM changes TDM bit stream into wavelengths between 1532 nm and

1560 nm

OT

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EDFA = Erbium Doped Fiber-optic Amplifier

Dense and Ultra Dense WDM

8

WDM 8 Lambdas

2.5 Gbps per lambda

1 1

8


2 2

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1

39

1

DWDM 40 Lambdas

40

10 Gbps per lambda

2 2

39

40EDFA = Erbium Doped Fiber-optic Amplifier

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190

UDWDM 192 Lambdas

191

40 Gbps per lambda

3

192

3

190

191

192



1 1

2 2




SONET DWDM


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Los estándares 802.3 de IEEEsuplemento año descripción

802.3a 1985 Original 802.3: 10BASE-5 10BASE-2 10BROAD-36

802.3c 1986 Especificaciones de repetidores

802.3d 1987 FOIRL (enlace de fibra)

802.3i 1990 10Base-T Ethernet sobre par trenzado de cobre

802.3j 1993 10Base-F Ethernet sobre fibra

802.3u 1995 100Mbps Ethernet

802.3x e 802.3y 1997 operación full duplex

802.3z 1998 1000Base-X (Gigabit Ethernet)

802.3ab 1999 1000Base-T (GE sobre par trenzado)

802.3ac 1998 Extensiones de trama (hasta 1522 bytes) para VLANs

802.3ad 2000 link aggregation

802.3ae 2002 10 GE

802.3af 2003 PoE (Power over Ethernet). Hasta 15W

802.3ah 2004 Ethernet in First Mile

802.3an 10 Gbase-T (en draft)

Bridging en 802.1D

802.1w Cambios y mejoras en el spanning tree

802.1s Múltiples spanning trees

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IEEE 802 standard

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Estándares de ethernet sobre optico ITU-T G.7041 Generic Framing Procedure (GFP) ITU-T X.86 Link Access Protocol (LAPS) ITU-T H.707 Virtual Concatenation (VCAT) ITU-T G.7042 Link Capacity Adjustment Scheme (LCAS) Otros: IEEE 802.1X Port Based Network Access Control IEEE 802.1D Ethernet switching IEEE 802.1Q Virtual LAN (VLAN) IEEE 802.1P Priorización de tráfico a nivel 2 IETF: MPLS Multi-Protocol Label Switching IEEE 802.17 Resilient Packet Ring (RPR) Ver:

http://grouper.ieee.org/groups/802/3/ http://grouper.ieee.org/groups/802/1/

http://grouper.ieee.org/groups/802/3/






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Trama ethernet

Los datos trasmitidos se encapsulan en un contenedor, que se llama trama

Este formato de trama DEFINE Ethernet Históricamente, existen dos tipos de tramas:

»802.3 Framing usa en campo de longitud de trama (Length) despues del campo de Source Address

»Ethernet II (DIX) Framing usa(ba) el campo de tipo de trama (type) despues del campo Source Address

Ambos tipos de tramas están definidos y soportados dentro de IEEE 802.3

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Trama ethernet

El tamaño de trama varía desde 64 a 1518 Bytes, excepto cuando se usa el identificador (tag) de VLAN

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802.1Q/P

User Priority- Defines user priority, giving eight (2^3) priority levels. IEEE 802.1P defines the operation for these 3 user priority bits.

CFI- Canonical Format Indicator is always set to zero for Ethernet switches. CFI is used for compatibility reason between Ethernet type network and Token Ring type network. If a frame received at an Ethernet port has a CFI set to 1, then that frame should not be forwarded as it is to an untagged port.

VID- VLAN ID is the identification of the VLAN, which is basically used by the standard 802.1Q. It has 12 bits and allow the identification of 4096 (2^12) VLANs. Of the 4096 possible VIDs, a VID of 0 is used to identify priority frames and value 4095 (FFF) is reserved, so the maximum possible VLAN configurations are 4,094.

Length/Type- 2 bytes. This field indicates either the number of MAC-client data bytes that are contained in the data field of the frame, or the frame type ID if the frame is assembled using an optional format.

Data- Is a sequence of nbytes (48=< n =<1500) of any value. The total frame minimum is 64bytes.

Frame check sequence (FCS)- 4 bytes. This sequence contains a 32-bit cyclic redundancy check (CRC) value, which is created by the sending MAC and is recalculated by the receiving MAC to check for damaged frames.

User Priority CFI Bits of VLAN ID (VIDI) to identify possible VLANs3 1 12

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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 Storage area networks (SANs) Metro transport (backhaul) VoIP

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

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Evolución de Ethernet

Optical EthernetEoMPLS

VPLSEoRPR

NG-SONET(EoS)Metro DWDM

Optical EthernetEoMPLS

VPLSRPR

NG-SONET(EoS)Metro DWDM

IP ADSLIP VDSLEPONEFM

Optical EthernetEoRPR

NG-SONET(EoS)

Acceso Distribución Metro Metro Core

GlobalInternet

ATMSONET/SDH

ATMSONET/SDH

ATM ADSLT1/E1

FRATM

GlobalInternet

Casa

MDU

STU

MTU

Residenci

alEm

presa

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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

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

CE

CE

CE

UNI

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

UNI

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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 más

UNIs del EVC: 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) 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 Bundling attribute Security filters attribute etc

Atributos de EVC: Parámetros de tráfico (CIR, PIR, in, out, etc) Parámetros de prestaciones (delay, jitter, etc) Parámetros de Clase de Servicio (VLAN-ID, valor de .1p, etc) Atributo de Service frame delivery Unicast frame delivery Multicast frame delivery etc

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Servicio Ethernet Line (E-Line)

Data

UNI

CE

CE

CE

Point-to-Point Ethernet Virtual Circuits

(EVC)

Metro Ethernet Network

1 or more UNIs

UNI

Video

IP PBX

Servers

Data

IP Voice

IP Voice

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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 CIR Normalmente en canales SDH (en NGN) 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 SLA´s Es similar al FR 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)

CE

CE

CE

Metro Ethernet Network

CE

Multipoint-to-Multipoint Ethernet Virtual Circuit

(EVC)

UNI

UNI

UNI

UNI

IP PBX

Servers

DataData

Data

IP Voice

IP Voice

IP Voice

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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: VPLS: Virtual Private Lan Service TLS: Transparent Lan Service VPSN: Virtual Private Switched Network

La separación de clientes vía encapsulación: las etiquetas de VLAN´s del proveedor no son suficientes (4096)

Es el servicio más rentable desde el punto de vista del proveedor.

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Metro tecnologías...

Los servicios Metro Ethernet services no necesitan que toda la red de nivel 2 sea ethernet; tambien puede ser:

Ethernet over SONET/SDH (EOS) Resilient Packet Ring (RPR) Ethernet Transport Ethernet sobre MPLS

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Implementaciones de los EVC (Ethernet Virtual Conn.)

Virtual Private LAN Services (VPLS) Es un tipo de VPN de nivel 2 La red del proveedor emula

la función de un conmutador de LAN ó bridge, para conectar todos los UNI del cliente, para formar una única VLAN

Los requerimientos en el CE son distintos a los de antes

Cada PE debe actuar como un bridge de ethernet

Se puede implementar poniendo ethernet en MPLS ó bien, haciendo stack de VLAN usando Q-in-Q

Ver http://vpls.org




SONET DWDM


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Taxonomy

WirelessNetworking

Multi-hop

Infrastructure-less(ad-hoc)

Infrastructure-based(Hybrid)

Infrastructure-less(MANET)

SingleHop

CellularNetworks Wireless Sensor

NetworksWireless Mesh

Networks

Car-to-car Networks(VANETs)

Infrastructure-based(hub&spoke)

802.11 802.16 Bluetooth802.11

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WLANs, El estándar IEEE 802.11 En el 1997 nace el:

IEEE Working Group for WLAN Standards:http://grouper.ieee.org/groups/802/11/index.html

Se define el MAC y tres diferentes niveles físicos, que operan a 1Mbps y 2Mbps: Infrarrojos (IR) en banda base Frequency hopping spread spectrum (FHSS), banda de 2,4 GHz Direct sequence spread spectrum (DSSS), banda de 2,4 GHz

IEEE Std 802.11a (diciembre 1999): Otro estándar de nivel físico: Orthogonal frequency domain

multiplexing (OFDM) Hasta 54 Mbps

IEEE Std 802.11b (enero 2000): Extensión de DSSS; hasta 11 Mbps

IEEE Std 802.11g (Junio 2003) Etc.

Data Link

Network

IEEE 802.2. LLCISO 8802.2

IEEE802.3

ISO8802.3

Network

DataLink

Physical

LLC

MAC

Ethernetv2.0 IEEE

802.11

ISO8802.11

http://standards.ieee.org/getieee802/802.11.html

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Arquitectura 802.11Estructura descentralizadaFlexible:

Redes pequeñas y grandes, Redes transitorias y permanentes

Control del consumo de potencia

Independent Basic Service Set (IBSS)

Componentes:Estación (STA)

Access Point (AP)

Basic Service Set (BSS)Extended Service Set (ESS)

infrastructure Basic Service Set (BSS)

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El MAC: entrega de datos fiable

CSMA/CA con binary exponential backoff

El protocolo mínimo consiste de dos tramas: DATOS+ACK

El standard propone RTS-CTS-DATOS-ACK

Point CoordinationFunction (PCF)

Distributed Coordination Function (DCF)

MAC

Servicios sin contienda Servicios con contienda

DIFS DIFS

PIFS

SIFS

ventana de contienda

defer access

busy medium

slot

Los 5 valores de timing:• Slot time• SIFS: short interframe space• PIFS: PCF interframe space (=SIFS+1slot)• DIFS: DCF interframe space (=SIFS+2slots)• EIFS: extended interframe space

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Mecanismo de detección de portadora

Se basa en el network allocation vector (NAV)

RTSDIFS

CTSSIFS

data

ACKSIFS SIFS

DIFS

NAV (RTS)NAV (CTS)

fuente

destino

otro STA

defer access

ventana de contienda

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QoS: 802.11e and WMM™

QoS needed for audio, voice, video Original Wi-Fi® didn’t have QoS IEEE 802.11e is new QoS standard

Still in process after more than 4 years Both “prioritized” and “guaranteed” QoS

WMM (Wi-Fi Multimedia) Prioritized QoS subset of 802.11e draft Widely accepted by 802.11e members Added to Wi-Fi certification in September 2004 Already included in some products

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WMM™ for Video

Source: Wi-Fi Alliance

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Bluetooth Specifications Bluetooth is a system solution comprising hardware,

software and interoperability requirements. The Bluetooth specifications specify the complete system.

De facto standard - open specifications. Two part document - Volume 1:Core and Volume 2:Profiles. Bluetooth specs developed by Bluetooth SIG.

February 1998: The Bluetooth SIG is formed promoter company group: Ericsson, IBM, Intel, Nokia, Toshiba

May 1998: The Bluetooth SIG goes “public” July 1999: 1.0A spec (>1,500 pages) is published December 1999: ver. 1.0B is released December 1999: The promoter group increases to 9

3Com, Lucent, Microsoft, Motorola February 2000: There are 1,500+ adopters

0.7 ---> 0.9 ---> 1.0A ---> 1.0B ---> 1.1 --> November 2003: release 1.2 Currently (November 2004), release 2.0

(aka EDR or Extended Data Rate) triples the data rate up to about 2 Mb/s

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release 2.0: the new partitioning

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Bluetooth usage Low-cost, low-power, short range radio a cable

replacement technology Common (File transfer, synchronisation, internet bridge,

conference table) Hidden computing (background synchronisation, audio/video

player) Future (PC login, remote control)

Why not use Wireless LANs? power cost

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Bluetooth RF 1 Mb/s symbol rate Normal range 10m (0dBm) Optional range 100m (+20dBm) Normal transmission power 0dBm (1mW) Optional transmission power -30 to +20dBm (100mW) Receiver sensitivity -70dBm Frequency band 2.4Ghz ISM band Gross data rate 1Mbit/s Max data transfer 721+56kbps/3 voice channels Power consumption 30uA(max), 300uA(standby),

~50uA(hold/park) Packet switching protocol based on frequency hop scheme

with 1600 hops/s

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Bluetooth Power Class Table

30m10m0dBm1mWClass 3

50m16m4dBm2.5mWClass 2

300m42m20dBm100mWClass 1

Range inFree SpaceExpected RangeMax Output PowerMax Output PowerPower Class

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Bluetooth Network Topology

Bluetooth devices have the ability to work as a slave or a master in an ad hoc network. The types of network configurations for Bluetooth devices can be three. Single point-to-point (Piconet): In this topology the network

consists of one master and one slave device. Multipoint (Piconet): Such a topology combines one master

device and up to seven slave devices in an ad hoc network.o Scatternet: A Scatternet is a group of Piconets linked via a

slave device in one Piconet which plays master role in other Piconet.

M

Si) Piconet (Point-

to-Point)

M

SS S

S

ii) Piconet (Multipoint)

M

S S S

M

S SMaster/Slave

iii) Scatternet

The Bluetooth standard does not describe any routing protocol for scatternets and most of the hardware available today has no capability of forming scatternets. Some even lack the ability to communicate between slaves of one piconet or to be a member of two piconets at the same time.

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Bluetooth stack: short version

RFBaseband

Link Manager

L2CAP

SDPRFCOMM

Applications

HCI

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Transport Protocol Group (contd.) Radio Frequency (RF)

Sending and receiving modulated bit streams

Baseband Defines the timing,

framing Flow control on the link.

Link Manager Managing the connection

states. Enforcing Fairness among

slaves. Power Management

Logical Link Control & Adaptation Protocol Handles multiplexing of

higher level protocols Segmentation &

reassembly of large packets

Device discovery & QoS

The Radio, Baseband and Link Manager are on firmware.

The higher layers could be in software.

The interface is then through the Host Controller (firmware and driver).

The HCI interfaces defined for Bluetooth are UART, RS232 and USB.

Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti RaoBLUETOOTH SPECIFICATION, Core Version 1.1 page 543

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Physical Link Definition Synchronous Connection-Oriented (SCO) Link

circuit switching symmetric, synchronous services slot reservation at fixed intervals

Asynchronous Connection-Less (ACL) Link packet switching (a)symmetric, asynchronous services polling access scheme

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Packet type Name Symmetric (kbps)

Asymmetric (kbps)

1 slot + FEC DM1 108.8 108.8 108.8

1 slot DH1 172.8 172.8 172.8

3 slot + FEC DM3 256.0 384.0 54.4

3 slot DH3 384.0 576.0 86.4

5 slot + FEC DM5 286.7 477.8 36.3

5 slot DH5 432.6 721.0 57.6

ACL data rates

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Single slot

Three slot

Five slot

fn fn+1 fn+2 fn+3 fn+4 fn+5

Multi-slot packets

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fn fn+1 fn+2 fn+3 fn+4 fn+5 fn+6 fn+7 fn+8 fn+9 fn+10 fn+11 fn+12

Master

Slave

Symmetric single slot

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MASTER

SLAVE 1

SLAVE 2

SLAVE 3

ACL ACLSCO SCO SCO SCO ACLACL

Mixed Link Example

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Bluetooth Connection States There are four Connection states on

Bluetooth Radio: Active: Both master and slave

participate actively on the channel by transmitting or receiving the packets (A,B,E,F,H)

Sniff: In this mode slave rather than listening on every slot for master's message for that slave, sniffs on specified time slots for its messages. Hence the slave can go to sleep in the free slots thus saving power (C)

Hold: In this mode, a device can temporarily not support ACL packets and go to low power sleep mode to make the channel available for things like paging, scanning etc (G)

Park: Slave stays synchronized but not participating in the Piconet, then the device is given a Parking Member Address (PMA) and it loses its Active Member Address (AMA) (D,I)

E

A

G

H

C

D

I

H

C

B

F

Master

Bluetooth Connection States

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Bluetooth Forming a Piconet Inquiry: Inquiry is used to find the

identity of the Bluetooth devices in the close range.

Inquiry Scan: In this state, devices are listening for inquiries from other devices.

Inquiry Response: The slave responds with a packet that contains the slave's device access code, native clock and some other slave information.

Page: Master sends page messages by transmitting slave's device access code (DAC) in different hop channels.

Page Scan: The slave listens at a single hop frequency (derived from its page hopping sequence) in this scan window.

Slave Response: Slave responds to master's page message

Master Response: Master reaches this substate after it receives slave's response to its page message for it.

Master

Inquiry

Inquiry Scan

Inquiry Response

Page

Page Scan

Slave Response

Master Response

ConnectionConnection

Slave

3

2

4

1

5

7

6

Forming a Piconet Procedures




SONET DWDM


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2G: Technology Summary

TDMA: Time Division Multiple Access Standardized in 1990 as IS-54 Provides 3-6 times capacity increase over AMPS (1G) Peak data rate of 14.4kpbs (can bundle up to 8 channels) Introduced authentication and encryption for security

GSM: Global System of Mobile communications Standardized in 1992, based on TMDA technology Improved battery life over TDMA GPRS peak data rates of 140 kbps; EDGE data rates of 180kbps

CDMA: Code Division Multiple Access Standardized in 1993 as IS-95 Provides 1.5-2 times capacity increase over TDMA Peak data rate of 14.4kpbs (can bundle up to 8 channels)

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2G: Winners & Losers

TDMA Marginally better capacity than GSM, marginally worse battery

life No evolution path beyond 2G – DEAD END !!

CDMA Lots of hype on capacity, delivered on upwards of 2x capacity

improvement over TDMA/GSM Clear evolution to 3G

GSM International Roaming and Compatibility Clear evolution to 3G Defacto Global Standard

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Evolution to 3GDrivers: Capacity, Data Speed, Cost

cdmaOne

GSM

TDMA

2G

PDC

CDMA2000 1x

First Step into 3G

GPRS 90%

10%

EDGE

WCDMA

3G phase 1 Evolved 3G

3GPP CoreNetwork

CDMA2000 1x EV/DO

HSDPA/HSUPA

Expected market share

EDGEEvolution

CDMA2000 EV/DO Rev A

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Mobile Networks Evolution

GPRS

EDGE

UMTS

HSDPA

2G3G

1995 2015

4G

2005

DownloadSpeed

1-10 Mbps

250-384 kbps

90-180 kbps

40 kbps

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GSM

HLR

GSM/GPRS Radio network

BSC

2G MSC

Externalvoice

network

GMSC

Packet switched Core network

External IPnetwork

GGSNPCU

2G SGSN

GPRS

3G = new network

UMTS/HSDPARadio network

RNC

UMTS/HSDPA

3G MSC

3G SGSN

Circuit switchedCore network

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3G Network = The Future

New network No voice overload Increased capacity by Spectrum efficiency

Better performances Higher throughput Faster download (Max 384kbps) Lower latency Faster browsing

Better Services Seamless hand-over to GPRS (service continuity) New way to design applications Video

Future proof technology : HSDPA

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3G/HSDPA for business innovation

Text messagingVoice

Push emailPhoto & Picture

MessagingCustomizedinfotainment

High speed internet accessHigh speed LAN access

3G / HSDPA

Video TelephonyMobile TV

Full track musicEnhanced email

2G/EDGE

SPEED

text picture video

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…and Beyond

Technology Convergence on OFDM (Orthogonal Frequency Division Multiple Access)

WIMAX Standardized by IEEE 802.16, evolution of 802.11 (Wi-Fi) Improved bandwidth, encryption and coverage over WiFi

Theoretical peak data rates of 70Mbps (practical peak ~2Mbps) Improved QoS better enables applications such as VoIP or IPTV Ideal application is for “last mile” connectivity to the home or

business Intel plans to embed WiMAX chips as part of ‘Intel Inside’

L3GTE/HSOPA Early standardization work starts in 3GPP R8 Improved bandwidth, latency over UMTS/HSxPA Radio technology based on MIMO-OFDM, peak data rates of up

to 70Mbps Network simplification

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Market Segments

Cordless

WiMAX 16eHSDPA to OFDMEV-DO to OFDM

WiFiLocal

Fixed

Voice Broadband

Cellular

WiMAX 16dDSL / CablePOTS

802.11a/b/g802.11n MIMO

Mesh

Dialup

2.5G

Mobile

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Service ControlPresence / GLMS

Applications

R4CDMAPSTN

Media Resources

TDM & Packet Interworking

PDF

HSS/AAA

Peer IPNetwork

Access Network

IP/MPLS Core

MultimediaServices

MessagingServices

Web / WAPServices

StreamingServices

MG15000

MGCF(CS2000)

CallSession

Controller

MRF

Audio/Video

PDGWLAN

ASNCSN

ASNWiMAX

GGSN

GPRSUMTS

EASGW

ASGHSOPAOFDM/MIMO

BRAS

PDG

GGSN

ASNCSN

ASGW

Network Convergence - IMSUnlicensed Mobile Access (UMA) and the IP Multimedia Subsystem (IMS) -- two standard architectures under the 3GPP umbrella -- both support fixed-mobile convergence (FMC). But their approaches to FMC have little in common. UMA is a highly constrained approach to a single service -- dual-mode access to GSM networks -- while IMS is an open platform for all types of services and all types of networks. UMA offers mobile network operators (MNOs) a quick fix, but IMS promises profitable new services and sustainable growth for all service providers.

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Market Trends

Media Convergence – Multiple Play Dual Play: High-Speed Internet & Fixed Line Triple Play: Dual Play + TV Quadruple Play: Triple Play + Wireless Challenge: Consolidated Invoice and Price Points

Fixed Mobile Convergence Dual Mode connectivity

Cellular / Cordless (DECT, ADSL/Bluetooth) WLAN / WWAN

Challenge: Technology standardization MVNO – Mobile Virtual Network Operator

Wireless Service Reseller, wholesales access from wireless operators

Discount & Lifestyle MVNO’s Segment, Product, Utilization Driven Challenge: Market Saturation & Service Differentiation

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Market Trends (continued)

Multimedia – use of several media types to convey information Effective information delivery across many disciplines: art,

education, telecommunications, medicine IMS enables multimedia services for mobile users

VoIP Challenge: User Interface, Form Factor, lack of “killer app”

Presence – Always on, always connected Combine Mobility & Reachability Effectively bring Popularity of IM to mobile phones (AOL,

Yahoo!, MSN, Skype) Opportunity for standardization & interworking based on

SIP/SIMPLE Challenge: Standardization & always on connectivity