WHOLESALE REQUIREMENTS FOR GPON & GENERIC ETHERNET ACCESS (GEA) Gavin Young Chief DATE 27 Architect, th SEPTEMBER 2007 C&W Access
OVERVIEW C&W NETWORK CONTEXT NEXT GEN ACCESS : BUILD vs BUY? WHOLESALE GPON ACCESS REQUIREMENTS
C&W NETWORK CONTEXT
ETHERNET WITHIN C&W NATIONAL DSL BROADBAND ACCESS NETWORK 800 DLEs covering ~ 55% of the UK Based upon DSL Forum TR-101 (Architecture encompasses Ethernet, QoS & Multicast) GigEthernet backhaul from MSANs Key differentiator w.r.t. cost, capacity, capability NATIONAL DEPLOYMENT OF METRO ETHERNET RINGS 10G & 20G MEN Rings Leverages MPLS Used for Broadband Access backhaul & business products ETHERNET PRODUCTS Point to Point Layer 2 Ethernet VPNs etc. via Fibre & Copper Access
DSL BROADBAND SERVICE ARCHITECTURE Designed to Accommodate Triple Play (ala DSL Forum TR-101) H-VLAN for H.248 (Primary Voice) M-VLAN for Multicast Video Multi-Service Core Voice MSANs C&W Metro Ethernet Internet Middle-mile GigE CinS-VLAN per subscriber
EXTENDING REACH TO OFF-NET CUSTOMER SITES WHOLESALE ACCESS PRODUCTS USED FROM CONSUMER BT / SME - DSL BROADBAND ACCESS Today : IPstream & Datastream (ADSL & SHDSL on an ATM architecture) Future : Wholesale Broadband Connect (ADSL2plus on a GigE architecture) Generic Ethernet Access (GEA) on GPON BUSINESS - ETHERNET ACCESS Today : Partial Private Circuits (e.g. 2M to 1GigE) WAN Extension Service (WES) products Future : Harmonized Ethernet products (Copper via EFM/SHDSLbis & fibre access used) Generic Ethernet Access (GEA) on GPON &/or VDSL2?
NEXT GENERATION ACCESS BUILD vs BUY
FUTURE ACCESS OPTIONS EFM, POINT-TO-POINT FIBRE & GPON User Curb Cabinet/Node Exchange. Metro Core VDSL2 FTTB Combo (ADSL2+) EFM/SHDSLbis FE/GE????? MSAN &/or Business Mux Ethernet/ IP/MPLS GPON VDSL2 FTTN INFRASTRUCTURE (fibre, ducts etc.) and EQUIPMENT (EFM card, OLT etc.) Could be C&Ws or provided by 3 rd parties via UNBUNDLED ELEMENTS &/or via bitstream WHOLESALE PRODUCTS Depending on geography
BUILD vs BUY THE TRADE-OFFS DIY : UNBUNDLED NETWORK ELEMENTS Lower incremental unit costs Product feature & development roadmap control End-end QoS & management control Geographic roll-out control BUT, needs deep pockets & future consolidation/failures could result in inefficient use of capital BIT STREAM WHOLESALE ACCESS Efficient network asset and hence capex utilization BUT, will it meet the feature requirements of wholesale customers? Will the time-to-market, deployment geography and price meet customer s needs? Without infrastructure competition, what will drive innovation?
WHAT WE VE SEEN HISTORICALLY ACROSS THE GLOBE CLECS LEAD THE WAY IN ACCESS INNOVATION & TIME TO MARKET Covad USA SDSL to business Fastweb Italy Triple-play over DSL, FTTB Free France Triple play over DSL, FTTB QSC Germany SDSL to vertical markets eaccess Japan DSL B2 Sweden FTTH C&W UK SDSL, 6 Mbit/s & rate-adaptive ADSL, ADSL2plus, MSAN double play (pre-bt 21CN), time-of-day based broadband etc.
WHOLESALE GPON ACCESS REQUIREMENTS
CONSUMER EXPERIENCE CONSISTANT WITH ADSL2PLUS ADSL2PLUS will dominate UK broadband access for a long time Need to be able to deliver the same baseline services over GPON Video (inc. multicast), Voice (as per MSANsoftswitch features), Internet Access (equivalent speeds) Maximal re-use of existing OSS B2B interfaces for ordering & assurance
GPON WITHIN BROADBAND ARCHITECTURE DSL Forum WT-156 : GPON FIT WITH TR-101 ETHERNET ARCHITECTURE NSP 1 /BNG Ethernet Regional Broadband Network Access Network Replaces DSL Access NSP 2 L2TP L2TS Access Node User 1 NSP 3 IP - QoS IP BNG Eth Agg OLT ODN ONT/ ONU RG T User 2 ASP 1 A10 IP - QoS V R S RAN U Customer Prem. Net
CUSTOMER PREMISES EQUIPMENT A KEY DOMAIN FOR SERVICE DIFFERENTIATION & BRANDING ATA for voice, different router to DSL, battery back-up Flexibility for future wires-only approach required so service provider can select price/functionality and innovate (key differentiator in DSL) Hence wholesale product has option of OLT+fibre only ONU provided by service provider OAM features are key for assurance Requires interface & management standards plus vendor interoperability It was thought equally impossible to have wires-only on DSL at one stage but all issues solved and we have a thriving retail CPE market!
CPE OPTION EXAMPLES FOR IMPROVED INTEGRATION OF FUNCTIONALITY HGU USER1 OLT ODN ON T RG USER2 V R S U T CPN HOME GATEWAY UNIT E1 /T1 / TDM pseudo wire OLT ODN SBU RG Intranet V R S U SINGLE BUSINESS UNIT
AGGREGATION & INTERCONNECT FLEXIBILE RANGE OF OPTIONS REQUIRED CENTRALIZED NATIONAL INTERCONNECT National & regional variants could exist For the early years where volumes of GPON customers are low Aggregation of users from multiple GPONs Leverages the wholesale GPON access provider s backhaul & core Requires resilience option DISTRIBUTED LOCAL INTERCONNECT Leverages DLE co-location (as per LLU) Leverages existing C&W backhaul & metro-ethernet networks More cost-effective to use own backhaul as volumes rise
SINGLE PRODUCT WITH MULTICAST OPTION GPON is inherently a broadcast transmission system It would seem crazy for anyone deploying GPON infrastructure not to offer multicast directly! Other GPON competitors in the UK are doing so V OLT ONU U IGMP (SPR) Replication function GPON GPON IGMP (SPR) Replication function RG Downstream multicast GEM port Upstream control plane path
QoS STANDARDIZED APPROACHES ala DSL Forum WT-156 & TR-101 SUPPORT FOR SME BUSINESS SERVICES Bandwidth upgrades Ability to transport TDM in SME voice scenarios (PWE3 encapsulation, jitter, synchronization)
QOS ARCHITECTURE & GPON MULTIPLEXING V U OLT ONU Traffic Management Classification GEM adaptation GPON GEM adaptation Classification RG Ethernet GEM Ethernet ONU G-PON interface Tcont A Tcont B PortID 22 PortID 6 PortID 12 T-Conts Per CoS Bundles of GEM ports ; serve as bandwidth allocation unit; Identified by A lloc-id GEM ports Contain flows from logical / physical ports; Identified by Port-ID GEM adaptation function; Map payload over GEM Class- Ification function Service ports
STANDARDS COMPLIENCE NOT JUST AT PHYSICAL LAYER ITU & FSAN have done a great job standardizing GPON Lots of focus on the PHY layer, however many open issues & degrees of freedom at higher layers DSL Forum (WT-156) working on how to glue a GPON access tail into a TR-101 (Ethernet) broadband architecture Need to agree standardized approach to VLAN, QoS and multicast approaches
MANY USE-CASES & DESIGN OPTIONS VLAN, GEM PORT & TCont MAPPING 1:1 TLS (Transparent LAN Service) C-tag ONU GEM Ports OLT Need distinct C-tag and S-tag tables S-tag S-tag + Pbits identifies GEM port 1:1 residential ONU GEM Ports OLT S-tag C-tag C-tag + Pbits identifies GEM port N:1 residential ONU GEM Ports OLT S-tag Learned MAC + Pbits identifies GEM port
STANDARDS ISSUES A FEW EXAMPLES FROM DSL FORUM WORK SO FAR Basics of VLAN mapping has been agreed but what about tagging at the ONU to facilitate virtualization for wholesale? QoS : Is a per customer approach OK without resorting to per customer per class? Are multiple GEM ports required or is one OK with queuing done at Ethernet layer? Is it fair to say that big packet header size & a need for fragmentation are not an issue at GPON speeds to control latency? GEM ports are uni-directional, but the same GEM port ID can be used in both directions to better fit existing architectures
OPERATIONS AND MAINTENANCE (OAM) Conformance to standards, maturity & interoperability of vendor solutions Ethernet equivalent to ATM F4/F5 flows etc. Underpins Assure process & interconnect commissioning
MISCELLANEOUS OTHER CONSIDERATIONS SECURITY Consumer : Robust enough to satisfy Hollywood/content owners Business : Government approval requires Layer 2 separation on shared infrastructure LOCATION OF SPLICING & SPLITTERS To facilitate re-patching for future upgrades to Point-to-point VIRTUALIZATION OF THE MANAGEMENT SYSTEM Via B2B interface for wholesale customer to view their own end-users to monitor/assure
SUMMARY OF KEY REQUIREMENTS FOR A GENERIC ETHERNET ACCESS / GPON WHOLSALE PRODUCT Price Product roadmap influence DSL architecture fit & service compatibility Management visibility & control (OAM interoperability) Option to provide integrated CPE with different features Maximal re-use of existing Broadband Access OSS B2B interfaces Aggregation & interconnect options Multicast QoS Security Standards compliant (not just PHY layer, include layers 2 & 3)