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Tema 1: Tecnologías de red.

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1 Tema 1: Tecnologías de red.
Estructura de Internet Redes “core” SONET DWDM Redes de acceso Redes cableadas: Ethernet et al. Redes inalámbricas: IEEE , UMTS et al.

2 What’s the Internet: “nuts and bolts” view
End systems Host computer Network applications Access networks Local area networks communication links Network core: routers network of networks local ISP company network regional ISP router workstation server mobile

3 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 NAP Tier-1 providers also interconnect at public network access points (NAPs) Tier 1 ISP Tier-1 providers interconnect (peer) privately Tier 1 ISP Tier 1 ISP

4 Sprint US backbone network
Tier-1 ISP: e.g., Sprint Sprint US backbone network DS3 (45 Mbps) OC3 (155 Mbps) OC12 (622 Mbps) OC48 (2.4 Gbps) Seattle Atlanta Chicago Roachdale Stockton San Jose Anaheim Fort Worth Orlando Kansas City Cheyenne New York Pennsauken Relay Wash. DC Tacoma

5 Internet structure: network of networks
“Tier-2” ISPs: smaller (often regional) ISPs Connect to one or more tier-1 ISPs, possibly other tier-2 ISPs Tier-2 ISPs also peer privately with each other, interconnect at NAP Tier-2 ISP Tier-2 ISP pays tier-1 ISP for connectivity to rest of Internet tier-2 ISP is customer of tier-1 provider Tier 1 ISP NAP Tier 1 ISP Tier 1 ISP

6 Internet structure: network of networks
“Tier-3” ISPs and local ISPs last hop (“access”) network (closest to end systems) local ISP Tier 3 Local and tier- 3 ISPs are customers of higher tier ISPs connecting them to rest of Internet Tier-2 ISP Tier 1 ISP NAP Tier 1 ISP Tier 1 ISP

7 Internet structure: network of networks
a packet passes through many networks! local ISP Tier 3 ISP local ISP local ISP local ISP Tier-2 ISP Tier 1 ISP NAP Tier 1 ISP Tier 1 ISP local ISP local ISP local ISP local ISP

8 Network Access Points (NAPs)
Note: Peers in this context are commercial backbones..droh Source: Boardwatch.com

9 MCI/WorldCom/UUNET Global Backbone
Source:

10 The situation in Europe
See:

11 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)

12 Who makes the rules? - ITU
ITU = ITU-T (telecom standardization) + ITU-R (radio) + development 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

13 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 address

14 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

15 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

16 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

17 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

18 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 and

19 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

20 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

21 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

22 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

23 Tema 1: Tecnologías de red.
Estructura de Internet Redes “core” SONET DWDM Redes de acceso Redes cableadas: Ethernet et al. Redes inalámbricas: IEEE , UMTS et al.

24 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

25 Time Division Multiplexing
Source 1 Source 2 Source 3 Source 4 Source 5 Source 6 MUX Sync Bit Time Slot1 Time Slot2 Time Slot3 Time Slot4 TimeSlot5 TimeSlot6 SyncBit Time Slot1 Time Slot2 Multiplexed Bit Stream Sum of sources = Total MUX’d bit stream SONET is fundamentally TDM Describe… Use it or lose it

26 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.

27 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

28 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

29 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.

30 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/Drop Multiplexer Terminal Section Line Path T3 OC-n

31 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 A1 A2 C1 87 columns Section Overhead B1 E1 F1 D1 D2 D3 STS-1 Payload H1 H2 H3 B2 K1 K2 D4 D5 D6 Line Overhead D7 D8 D9 D10 D11 D12 Z1 Z2 Z3

32 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.

33 Traditional View of Routers and Links
When Internet architects and IP experts design networks, they usually draw routers on the edges of fluffy clouds – the clouds are left to represent the transmission systems they are uninterested in, and have no view into anyway. To the clouds, the IP data layer is just another client anyway. <click> We also usually see interconnecting lines showing a full mesh between router nodes, but…..they are simple straight line representations with no clue of what is really happening. So, let’s strip away the fluffy clouds and take a look at the transmission system underneath ! As you can see, it looks quite complex – a combination of long haul point to point connections, metro area rings, premises delivery points. We could just as easily add many other components to this view, which represent other transmission system clients such as voice switches, ATM equipment, Frame Relay switches and so on. Lets just keep it simple and look a the data client – the router.

34 Reality has always been more complex
Terminal Multiplexer Terminal Multiplexer SONET/SDH ADM SONET/SDH DCS SONET/SDH ADM SONET/SDH ADM SONET/SDH DCS SONET/SDH ADM Terminal Multiplexer SONET/SDH DCS Terminal Multiplexer SONET/SDH ADM SONET/SDH ADM It really looks more like this (still simplified) 10:06am Terminal Multiplexer Terminal Multiplexer

35 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 Shift from copper to fiber - many benefits Multimode fiber - up to 2km - large glass core ( 62.5 or 50 microns ) Singlemode fiber - less interference - core smaller 8-19 microns - 100km signal distances. - min attenuation at 1310, - min dispersion at 1550 Non-Zero dispersion shifted fiber - min attenuation and dispersion at same point - Optical Amplifiers As a data guy: This is getting a whole lot better :-) 9:58am

36 Wave Division Multiplexing
SONET/SDH ADM Single Fiber SONET/SDH ADM SONET/SDH ADM From One Wavelength Per Fiber to Many ADM ADM WDM Node WDM Node ADM ADM OT OT ADM Compare TDM (SONET) to WDM. 10:16am ADM Single Fiber ADM ADM OT = Optical Transponder

37 WDM System Elements SONET/SDH ADM SONET/SDH ADM SONET/SDH ADM
Common to join SONET/SDH rings using WDM fiber optic equipment allows more capacity over further distances - but has a finite limit - needs signal regeneration. In the past - light paths back into electrical signals, - split back into lambdas As number of wavelengths grow - cost of regeneration grows - regeneration equipment needs to be updated We will revisit this. SONET/SDH ADM SONET/SDH ADM = Regenerators

38 TDM and WDM Relationship
Laser Output l1 l1 … ln OT ln Similar and different 10:19am TDM generates output from sum of inputs into a single bit stream WDM changes TDM bit stream into wavelengths between 1532 nm and 1560 nm

39 Dense and Ultra Dense WDM
WDM 8 Lambdas l1 l2 l2 2.5 Gbps per lambda l8 l8 WDM can me just 2 lambdas into a fiber As number lambdas increases, smaller inter-lambda gap - receivers have to be of higher quality When WDM first became commercially available, 2.5Gbps was typical (OC48) EDFA = Erbium Doped Fiber-optic Amplifier EDFA = Erbium Doped Fiber-optic Amplifier

40 Dense and Ultra Dense WDM
DWDM 40 Lambdas 10 Gbps per lambda l39 l39 l40 l40 higher densities and bandwidth - current typically 40 lambdas * OC192. EDFA = Erbium Doped Fiber-optic Amplifier

41 Dense and Ultra Dense WDM
UDWDM 192 Lambdas l3 40 Gbps per lambda l190 l190 l191 l191 Future... Note EDFA devices... 10:41am EDFA = Erbium Doped Fiber-optic Amplifier l192 l192

42 Tema 1: Tecnologías de red.
Estructura de Internet Redes “core” SONET DWDM Redes de acceso Redes cableadas: Ethernet et al. Redes inalámbricas: IEEE , UMTS et al.

43 Los estándares 802.3 de IEEE suplemento 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 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

44 IEEE 802 standard

45 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 Resilient Packet Ring (RPR) Ver:

46 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

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

48 Bits of VLAN ID (VIDI) to identify possible VLANs
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 VLANs 3 1 12

49 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 !!

50 Evolución de Ethernet Acceso Distribución Metro Metro Core Residencial
Casa Residencial MDU ATM ADSL T1/E1 FR ATM ATM SONET/SDH ATM SONET/SDH Global Internet STU Empresa MTU Optical Ethernet EoMPLS VPLS EoRPR NG-SONET(EoS) Metro DWDM Optical Ethernet EoMPLS VPLS RPR NG-SONET(EoS) Metro DWDM IP ADSL IP VDSL EPON EFM Optical Ethernet EoRPR NG-SONET(EoS) Global Internet

51 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 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 UNI Metro Ethernet Network (MEN) CE UNI CE

52 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.

53 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.

54 Atributos Atributos de UNI: Atributos de EVC:
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

55 Servicio Ethernet Line (E-Line)
Point-to-Point Ethernet Virtual Circuits (EVC) Servers IP Voice UNI IP PBX CE Metro Ethernet Network Data CE 1 or more UNIs Video IP Voice UNI CE Data

56 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

57 Servicio Ethernet LAN (E-LAN)
CE Metro Ethernet Network Multipoint-to-Multipoint Ethernet Virtual Circuit (EVC) UNI IP PBX Servers Data IP Voice

58 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.

59 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

60 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

61 Tema 1: Tecnologías de red.
Estructura de Internet Redes “core” SONET DWDM Redes de acceso Redes cableadas: Ethernet et al. Redes inalámbricas: IEEE , UMTS et al.

62 Taxonomy Wireless Networking Single Hop Multi-hop Infrastructure-based
(hub&spoke) Infrastructure-less (ad-hoc) Infrastructure-based (Hybrid) Infrastructure-less (MANET) 802.11 802.16 802.11 Bluetooth Cellular Networks Car-to-car Networks (VANETs) Wireless Sensor Networks Wireless Mesh Networks

63 WLANs, El estándar IEEE 802.11 En el 1997 nace el:
IEEE Working Group for WLAN Standards: 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 a (diciembre 1999): Otro estándar de nivel físico: Orthogonal frequency domain multiplexing (OFDM) Hasta 54 Mbps IEEE Std b (enero 2000): Extensión de DSSS; hasta 11 Mbps IEEE Std g (Junio 2003) Etc. Data Link Network IEEE LLC ISO IEEE 802.3 ISO 8802.3 Data Link Physical L L C M A C Ethernet v2.0 802.11

64 Arquitectura 802.11 Estructura descentralizada Flexible:
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)

65 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 Coordination Function (PCF) Distributed Coordination Function (DCF) MAC Servicios sin contienda Servicios con contienda 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 DIFS PIFS SIFS ventana de contienda defer access busy medium slot

66 Mecanismo de detección de portadora
Se basa en el network allocation vector (NAV) DIFS fuente RTS data SIFS SIFS SIFS destino CTS ACK DIFS NAV (RTS) ventana de contienda otro STA NAV (CTS) defer access

67 QoS: 802.11e and WMM™ QoS needed for audio, voice, video
Original Wi-Fi® didn’t have QoS IEEE e 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 e draft Widely accepted by e members Added to Wi-Fi certification in September 2004 Already included in some products

68 WMM™ for Video Source: Wi-Fi Alliance

69 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 > > 1.0A ---> 1.0B ---> > 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

70 release 2.0: the new partitioning

71 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

72 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 kbps/3 voice channels Power consumption 30uA(max), 300uA(standby), ~50uA(hold/park) Packet switching protocol based on frequency hop scheme with hops/s

73 Bluetooth Power Class Table
30m 10m 0dBm 1mW Class 3 50m 16m 4dBm 2.5mW Class 2 300m 42m 20dBm 100mW Class 1 Range in Free Space Expected Range Max Output Power Power Class Redes de Computadores II 73

74 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. Scatternet: A Scatternet is a group of Piconets linked via a slave device in one Piconet which plays master role in other Piconet. 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. M S i) Piconet (Point-to-Point) ii) Piconet (Multipoint) Master/Slave iii) Scatternet Redes de Computadores II 74

75 Bluetooth stack: short version
Applications RFCOMM SDP L2CAP HCI Link Manager Baseband RF

76 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. BLUETOOTH SPECIFICATION, Core Version 1.1 page 543 Source: Farinaz Edalat, Ganesh Gopal, Saswat Misra, Deepti Rao

77 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

78 ACL data rates

79 Multi-slot packets fn fn+1 fn+2 fn+3 fn+4 fn+5 Single slot Three slot
Five slot

80 Symmetric single slot fn fn+1 fn fn fn fn fn fn+7 fn fn fn fn+11 fn+12 Master Slave

81 Mixed Link Example SCO ACL ACL ACL ACL MASTER SLAVE 1 SLAVE 2 SLAVE 3

82 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 B F Master Bluetooth Connection States Redes de Computadores II 82

83 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 Connection Slave 3 2 4 1 5 7 6 Forming a Piconet Procedures Redes de Computadores II 83

84 Tema 1: Tecnologías de red.
Estructura de Internet Redes “core” SONET DWDM Redes de acceso Redes cableadas: Ethernet et al. Redes inalámbricas: IEEE , UMTS et al.

85 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 times capacity increase over TDMA

86 2G: Winners & Losers TDMA CDMA GSM
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 Defacto Global Standard

87 Evolution to 3G Drivers: Capacity, Data Speed, Cost
Expected market share 90% TDMA EDGE EDGE Evolution 3GPP Core Network GSM GPRS WCDMA HSDPA/HSUPA PDC cdmaOne CDMA x 10% CDMA x EV/DO CDMA2000 EV/DO Rev A 2G First Step into 3G 3G phase 1 Evolved 3G

88 Mobile Networks Evolution
Download Speed 1-10 Mbps kbps kbps 40 kbps 4G HSDPA UMTS 3G 2G EDGE GPRS 2015 1995 2005

89 3G = new network GSM GPRS UMTS/ HSDPA Packet switched GSM/GPRS
Core network GSM/GPRS Radio network 2G SGSN 3G SGSN GGSN PCU External IP network BSC GSM GPRS HLR UMTS/ HSDPA UMTS/HSDPA Radio network RNC 2G MSC GMSC 3G MSC External voice network Circuit switched Core network

90 3G Network = The Future New network Better performances
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

91 3G/HSDPA for business innovation
text  picture  video High speed internet access High speed LAN access Video Telephony Mobile TV Full track music Enhanced Push Photo & Picture Messaging Customized infotainment Text messaging Voice 2G/EDGE 3G / HSDPA SPEED

92 …and Beyond Technology Convergence on OFDM (Orthogonal Frequency Division Multiple Access) WIMAX Standardized by IEEE , evolution of (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

93 Cellular Cordless WiFi POTS Market Segments Mobile 2.5G Local Fixed
Voice Mobile Broadband WiMAX 16e HSDPA to OFDM EV-DO to OFDM Cellular 2.5G Local 802.11a/b/g 802.11n MIMO Mesh Cordless WiFi Fixed WiMAX 16d DSL / Cable POTS Dialup

94 Network Convergence - IMS
Unlicensed 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. Access Network Applications Media Resources PDG PDG Multimedia Services Messaging Services Web / WAP Services Streaming Services Audio/ Video WLAN MRF GGSN GGSN Service Control GPRS UMTS TDM & Packet Interworking Presence / GLMS ASN CSN ASN CSN HSS/AAA Call Session Controller WiMAX R4 CDMA PSTN ASN MGCF (CS2000) PDF ASGW EASGW MG15000 HSOPA OFDM/MIMO ASG IP/MPLS Core Peer IP Network BRAS

95 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

96 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


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