Access networks – Services Department of Budapest University of Technology and Economics Telecommunications and Media Informatics
What services? - Triple Play BME-TMIT Page 2
Triple Play – economical reasons BME-TMIT Video inflection point Video+VoIP > Best Effort => Triple Play architecture Voice/data inflection point Internet > Voice => Best Effort (WWW) Triple Play service Architecture Source: Alcatel Page 3
Convergence BME-TMIT ● Service convergence ● Device convergence ● Network convergence Page 4
The network convergence BME-TMIT One provider- everywhere Common services Common profile IMS Common billing Beneficial for Provider Provider Network User Home environment Office environment Mobile environment Page 5
Changing Trends BME-TMIT ● Fixed line based services are decreasing ● Mobile users are increasing despite that penetration is high ● Broadband Internet installations are increasing Fixed Mobile Broadband Page 6
Convergence of operators BME-TMIT Page 7 Video Voice Data Mobile (TV) Telecom Cable Mobile
Video services BME-TMIT ● IPTV – Broadcast ● SDTV ● HDTV ● Typical implementation: Multicast ● VoD – Video on Demand ● Bandwidth depends on content quality ● Typically unicast ● Other services (Time-shift, etc) – do not represent different requirements Page 8
Video service architecture BME-TMIT Aggregation TV Source HGW Edge STB Video Server ADSL2+ Router or VDSL DSLAM Home First Ethernet network Mile aggregation (DSL) Page 9
VoD vs. IPTV BME-TMIT ● A VoD service requires higher bandwidth! ● IPTV broadcast, 300 channel bandwidth demand ● 300 MPEG-2 channel, 1.5Mbit each =~1Gigabit ● VoD bandwidth demand – depends on # of users ● 20000 user 10%-os peak usage =~7.5Gbps ● The IPTV is more important – priority over the VoD ● High availability => overprovisioning, protection Page 10
Voice services - VoIP BME-TMIT ● VoIP – cost effective ● The HGW has gateway function or IP phone is required ● Service convergence ● VoIP protocols ● IP, TCP, UDP (User Datagram Protocol) ● RTP (Real Time Protocol), RTCP (Real Time Control Protocol) ● SIP (Session Initiation Protocol), H.323 (ITU-T) Page 11
VoIP service architecture BME-TMIT Coding, Jitter Transport Decoding framing, Buffering buffer queuing PSTN Aggregation HGW Edge ADSL2+ Router Soft- or VDSL switch DSLAM Home First Ethernet network Mile aggregation (DSL) Page 12
Data communication- HSI BME-TMIT ● Typical usage ● Internet access ● VPN access ● Requirements ● Best Effort ● 1.5-2 Mbps usually enough – Except heavy p2p Page 13
HSI service architecture BME-TMIT Internet Aggregation HGW BRAS ADSL2+ PC or VDSL DSLAM PPPoE Page 14
Triple-Play network requirements BME-TMIT ● Video ● HS Internet ● Low delay, low jitter, no loss ● Guaranteed bandwidth ● High bandwidth ● Possible bursty tranfer ● Effective broadcast/multicast ● Business users mechanism ● Guaranteed bandwidth ● VoD scalability ● Low packet loss ratio ● Below 1 sec recovery ● 50ms protection ● Voice ● General ● Low delay and Jitter ● Good cost/performance ratio ● Low loss ● Signaling support ● Sub-second recovery in case of ● Network – service cooperation failure ● Support for resilient architecture Page 15
Generic service architectures - Access network- Department of Budapest University of Technology and Economics Telecommunications and Media Informatics
Service Architecture BME-TMIT STB Source DSL Video Video Server RGW DSLAM ? SoftSwitch PBX Voice STB Internet Coax RGW HSI Page 17
Ethernet in the MAN BME-TMIT ● Large scale deployment anticipated ● MAN - Metro Ethernet ● First mile: EPON, GPON ● „ Carrier grade ” requirements: ● Scalability: many thousands of users ● Restoration, protection: high availability required (5x9), 50ms ● Service management (OAM) ● QoS support: SLA, guarantee ● Security ● Ethernet based services ● Standardization in progress Page 18
Standardization BME-TMIT ● MEF: services – from user perspective ● ITU-T: services – from network perspective, restoration and protection ● IEEE: Higher level functions: Ethernet OAM, provider bridges, EPON ● IETF: Ethernet over MPLS (Ethernet wire) és VPLS (Virtual Private LAN Service) Page 19
Single-Edge architecture BME-TMIT PPPoE STB Source DSL Video Video Server RGW DSLAM SoftSwitch PBX Voice STB Internet Coax RGW HSI Page 20
Single Edge - 2 BME-TMIT ● Old fashioned architecture ● PPPoE tunnel to the BRAS ● Strengths ● Authentication ● Traffic containment ● Security ● Drawbacks ● Multicast is not possible – Big disadvantage for IPTV! Page 21
Multi-Edge architecture BME-TMIT STB Forrás DSL Video Video Server RGW DSLAM BNG SoftSwitch PBX Voice STB Internet BRAS Coax RGW HSI Page 22
Multi-Edge architecture- 2 BME-TMIT ● Internet access still uses PPPoE ● Internet access through the BRAS ● VoIP and Video uses IPoE ● IP address by DHCP ● Service access through BNGs ● Advantages ● Multicast possibility ● Less overhead ● Lower load at the BNG Page 23
IPoE and PPPoE BME-TMIT ● PPPoE – Point to Point Protocol ● Authentication: user/pass, line ID ● PPP tunnel ends in the BRAS ● Connection oriented ● Not all devices support ● IPoE – DHCP ● Authentication: MAC addr, +DHCP option line ID ● „ flat rate online” ● Connectionless, Multicast is possible ● All devices support Page 24
PPPoE overhead BME-TMIT ● PPPoE ● Two level L2 encapsulation ● 10 byte overhead for each packet ● PPPoE supports only point-to-point ● IPoE ● Fancy name for the basic IP/Ethernet encapsulation Page 25
IPoE and PPPoE : requirements BME-TMIT ● In both cases the authentication can be done at the DSLAM ● PPP termination is required at the DSLAM ● PPPoE ● PPPoE intermediate agent is required to add additional information to PPPoE packets ● IPoE ● DHCP option 82 for line identification ● DHCP relay agent to convert DHCP request to unicast Page 26
Definitions Auto configuration and AAA BME-TMIT Autoconfiguration: process of establishing a connection AAA Authentication – process of determining whether someone or something is, in fact, who or what it is declared to be. – based on identifiers and security attributes. – part of an actual access to a network/service in the context of a SLA or contract, and often is linked with a fee (Accounting) Authorization – process of giving individuals access to system objects based on their identity. Accounting – recording, classifying, summarizing, and interpreting of events of a financial character in a significant manner
Autoconfiguration: PPP model BME-TMIT ● Characteristics : ● PPP = Point-to-Point Protocol ● PPP session performs (between CP modem - PPP peer) – Link establishment (LCP packets) – Authentication (optional, PAP or CHAP) – Network-layer protocol (NCP packets : eg IPCP: CP gets its IP@) ● PPP encapsulation stays during session ● Origin of PPP for Internet Access via voice band modems (fig.) ● Continued to be used in DSL Modem RAS Internet Modem PSTN bank
PPPoE BME-TMIT ● PPPoE needed when PPP transported over Ethernet: allows – transport over shared medium IP IP – PPP session multiplexing PPP PPP ● Autoconfig Procedure : PPPoE PPPoE 802.3 MAC 802.3 MAC - Detection of server(s): PPPoE Active Discovery Initiation (PADI) RFC 2684 - Server(s) reply : AAL5 PPPoE Active Discovery Offer (PADO) ATM - Choice of server : PPPoE PPPoEoA PPPoE Active Discovery Request (PADR) - Server confirmation : PPPoE Active Discovery Session-confirmation (PADS)
PPPoE initialisation BME-TMIT PPPoE Modem Access Node Ethernet PPPoE Client Terminator Switch Server in Edge Node <PADI> <PADI> <PADI> Ethernet: <PADI> Ethernet: - DA: Broadcast Ethernet: - SA: User MAC@ - DA: Broadcast Ethernet: - S-VLAN ID PPPoE: - SA: User MAC@ - S-VLAN ID - (C-VLAN ID) - ISP-Name PPPoE: - (C-VLAN ID) - DA: Unicast/Multicast - ISP-Name - DA: Unicast/Multicast - SA: User MAC@ - SA: User MAC@ PPPoE: - ISP-Name PPPoE: - ISP-Name <PADO> <PADO> <PADO> Ethernet: Ethernet: <PADO> - S-VLAN ID - S-VLAN ID Ethernet: - (C-VLAN ID) Ethernet: - DA: User MAC@ - (C-VLAN ID) - DA: User MAC@ - SA: Server MAC@ - DA: User MAC@ - DA: User MAC@ - SA: Server MAC@ - SA: Server MAC@ PPPoE: - SA: Server MAC@ PPPoE: PPPoE: PPPoE: - ISP-Name - ISP-Name - ISP-Name - ISP-Name <PADR> <PADR> <PADR> <PADR> Ethernet: Ethernet: Ethernet: Ethernet: - DA: Server MAC@ - DA: Server MAC@ - S-VLAN ID - S-VLAN ID - SA: User MAC@ - SA: User MAC@ - (C-VLAN ID) - (C-VLAN ID) - DA: Server MAC@ - DA: Server MAC@ - SA: User MAC@ - SA: User MAC@ <PADS> <PADS> <PADS> <PADS>
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