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Next Generation BRAS

Truman Boyes Professional Services APAC truman@juniper.net. Next Generation BRAS. Access Technologies for Consumer Broadband. Agenda. Welcome. Where is Broadband Going? What Issues are we solving? What are the methodologies that we are using to solve these issues?

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Next Generation BRAS

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  1. Truman Boyes Professional Services APAC truman@juniper.net Next Generation BRAS Access Technologies for Consumer Broadband

  2. Agenda • Welcome. • Where is Broadband Going? • What Issues are we solving? • What are the methodologies that we are using to solve these issues? • Carriers to enter voice and video market • Digital Media Gateway • Speeds to increase ; needing more capacity…

  3. Triple Play : VIDEO • The most complex of all services. • The most bandwidth • The most noticeable in terms of quality. • How is it delivered? Set Top Box. MS IPTV probably dominating in this area. BW 1.5-1.8Mbps for normal TV. 7-9Mbps for HD compressed. • HQOS is still extremely important for this service. It’s enabled on the BNG.

  4. Triple Play: Video (CONT) • Resources are critical when delivering video content. • Multicast is the resources solver. • But where do we want to save bandwidth? • As close to the customer as possible and everywhere back to the source. • IGMP snooping in DSLAM. IGMP multicast replication in DLSAM saves bandwidth between the BNG and DSLAM. • Allow sharing of bandwidth between unicast and multicast traffic for access interface. (This is where HQoS can help).

  5. Video Head End or ASP ISP (Internet) Enterprise VPNs DSLAM Multicast - Overview • Single M- VLAN for all requested channels, i.e.: M-VLAN carries the channels actually requested, over broadcast approach and static broadcast of top 20 groups. Single M-VLAN for video channels ASP (e.g. IP Telephony) Internet Port C-VLAN per Subscriber IPTV Port IP Backbone • Performs Transparent IGMP Snooping. MAC filters and multicast replication • RG provides a single VC connection between home and DSLAM • IPoE and 1483B session (video/IGMP-Proxy) • IGMP joins received on subscriber interface • Adjusts (unicast) VLAN shaper in QoS h-scheduler to reflect MC traffic Reasoning: DSL Forum base WT-101 & TR-59 compliant. Simple single VC scheme, bandwidth fully optimized and dynamically balanced. IP QoS and stats restored. Works with PPPoE!!!

  6. Subscriber VC The second function of IGMPDynamic QoS adjustment VoIP / VoD 5. Unicast Scheduler (C-VLAN) adjusted IPTV Headend Internet 4. IGMP OIF map to MC-VLAN 3. IGMP/C-VLAN Processed 6. MC Video Session forwarded over MC VLAN 2. IGMP Snooping Subscriber VLAN Multicast VLAN 1. IGMP (PPPoE or IPoE) 7. Final MC Replication

  7. Customer to Service Relationship • If the carrier sells circuits, it may be wise to apply the 1:1 customer to C-VLAN model. • May “map” port to C-VLAN, so customer has single VC to the RG and single C-VLAN interface on BNG. • Easy to apply QoS to single identifier. • N:1 Model for true distinction between services. • The services run on different logical links. HQOS become an issue. • Provisioning and Troubleshooting multiple l2 interfaces for a single customer will prove to be a challenge.

  8. Multi-Service Edge Routing (BSR) • IP VPNs • Stacked VLANs per customer site • VLAN auto-sensing, no OPEX • PPP and DHCP (and routed IP) • DHCP sessions may be aggregated • Hierarchical IP QoS ; per user, per flow • One ATM VC per household • Usually one IP @ for consumers • Could convey 1..N PPP / DHCP sessions • IP Subnet(s) for business sites • Can optionally support multi-VCs, with Ethernet QoS mapping (single C-VLAN). Video Head End or ASP ISP (Internet) Enterprise VPNs • One C-VLAN per port • S-VLAN added by DSLAM or Aggregation NW Node • Optional: frames marked with Eth priority within a VLAN • Optional: Sub/Line ID • Multicast: • IGMP Snooping • M-VLAN – N:1 • Multicast Replication & x-connect WT-101: 1:1 VLAN Solution Multi-Service BSR DSLAM RG ASP (e.g. IP Telephony) C-VLANs Internet Port Optional IPTV Switch IP Backbone VoIP • Optional: Separate Edge for BIZ • Same as 1:1 as each port is directed to a single edge

  9. One or more ATM VC (and IP@) per service • Internet or VPN Access • IP/Video Telephony • Broadcast TV • Video streaming (unicast) • Gaming? Storage? • Per VC: Protocol Based X-Connect – IP or PPP (via ETHERTYPE); other RG – Marking VLAN • ATM may be removed from the local loop (EFM) Video Head End or ASP ISP (Internet) Enterprise VPNs WT-101: N:1 VLAN Solution • Multiple Service Nodes or “Broadband Gateways” • QoS architecture: non standard H-QoS, DiffServ++ • SLAs • Lawful intercept per BNG • Security & OAM challenges (see other slides) • Provisioning Overhead on AN, Aggregation NW, BNG BRAS Service VLANs Service Node with MC DSLAM RG Internet Port IPTV Switch Service Node + SBC ASP (e.g. IP Telephony) Switch VoIP Service Node • One VLAN per consumer “service” • Some QoS Semantics in VID • Some QoS Semantics in .1p • One VLAN per business site • Mixing of VLAN schemes • M-VLAN – N:1 • Line ID via PPPoE IA & DHCP Op82 Business Site

  10. One BNG to rule them all • Policy enforcement is clear with a single BNG as access point into the SP net. • Multicast / HQOS is easy (at least the “carving” of the bandwidth between services at a single point is easy. • Lawful Intercept in a single location reduces the admin work. • What about L2C between BNG and DSLAM to obtain correct sync rates between customer and DSLAM.

  11. Migrations from existing BRAS/ACCESS • Many SP’s have ATM DSLAMs, ATM networks, that connect to MPLS/IP cores • As we move to Ethernet it makes sense to use protocols that are better suited for Ethernet: PPPoE. Why does it suite? • Client/Server instead of just point to point. • Protection on ethernet segments • Allows a move away from ATM infrastructure. • BNGs can start to support both PPPoA and PPPoE, and of course, PPPoEoA. • Some DSLAMS are implementing PPPoA to PPPoE translation. Be warned about MTU issues. PPPoE max MTU is 1492, many modems do not support MSS clamping, and PMTU discovery is not always going to work. • Draft: draft-arberg-pppoe-mtu-gt1492 • PPPoA ---> PPPoE -----> DHCP when possible.

  12. If you build it they will need to be trunked • VPLS/ Kompella / PWE3/ trunking of Ethernet from some regions to a centralized BNG. • Grows a network quicker in some cases. • Make the choice to trunk or deploy BNG based on population densities and what equipment/infrastructure do you have in that region. • BNG’s could also provide trunking of some traffic back to other PE.

  13. BRAS PE • Past 4-5 yrs we have been building MPLS networks because they give us: • Fast re-route, link protection, node protection • Signaling of BW • Isolation of routing tables • BW reservations (ie. Reserve and possibly police LSP traffic from BRAS) • Why not enjoy the same benefits in BRAS networks ? • BRAS as dual homed PE direct to P nodes. Remove dependence on existing PE’s (potentially makes these nodes *more* available)

  14. High Availability on BRAS • PPP State Replication • DHCP state replication • All routing protocol state preserved between routing engines / SRPs / controllers. • Software faults do happen, but can your network handle 30k subscribers being dropped and reconnecting? • Software patches on the fly. Upgrade specific applications on BNGs, ie. DHCP local server to support new option. Moves away from monolithic operating system maintenance.

  15. Service Activations / Alterations Now • BW policy changes that are activated by a customer through a portal. • Could be captive portal or user initiated • Service Change • 7Mbps xDSL line. Shaped to 1M. User wants to download an ISO image; can increase service speed to line rate for period of time. • User subscribes to policy that blocks incoming traffic at the SP. • Could allow differentiated billing on volume for specific services. IE. Billable internet data, and all you can eat local content. Free to the provider traffic.

  16. NGN Broadband in Summary • Broadband is changing • More services , speeds • More importance on the services • Means more Reliability is necessary • Carriers will be digital media gateways. Not the media companies : but the ppl that bring it to you. • Adoption of mechanisms like HQOS and DSLAM multicast replication are key to scaling and guaranteeing the right delivery of service. • Resiliency is extremely important. We are spending time to build these networks. Lets built it once the right way so that it can last at least 5-6 years.

  17. Thank You APRICOT 06! Truman@juniper.net

  18. Broadband Today • ADSL, Cable, WiFi, Metro Ethernet • North America dominating cable markets but growing in DSL deployment. • DSL in Asia / Europe / Americas • WiFi in rural areas for last mile. Also available in highly populated areas for short range use. • 3G dedicated access to augment this WiFi market. • Ethernet delivery is cheap, and scalable to deploy in populated areas. Connecting multi-unit buildings for residential and business customers.

  19. WT-101 Background WT-101 was born out of the desire of SP to take advantage of the benefits of Ethernet, which are primarily cost & simplicity and which align with general move to packet based NGN Participants actively involved • SP: BT, Bellsouth, DT, FT, Telecom Italia , Singtel • Vendors: Juniper, Alcatel, Cisco, Ericsson, Redback, Huawei, Fujitsu Network Architecture Philosophy • Simplest Architecture Possible (basic network design) • Simple L2(-only) Access Node • Edge Architectures: Single Edge, Dual Edge (Video & Other)Multiple Edge – outside of scope, however if req, principles should be extended Business Models • Based on Multi-Service Business Requirements defined in TR-058 • Additional specification in WT-102 New term in WT-101: Broadband Network Gateway (BNG) Defined as a device that implements a subset of BRAS requirements (defined in TR-092) with additional requirements in WT-101

  20. Access Node Port (1:1) / Protocol (N:1) based x-connect Restricted 802.1d bridging Multicast: IGMP: Snooping, Report Suppression/Proxy Reporting Multicast VLAN: replication and x-connect to Subscriber ports IWF for PPPoA Line ID: PPPoE IA; DHCP Op82 Encapsulation & Line Params Signalling Bulk Provisioning Ethernet Aggregation Network Only Ethernet requirements – network architecture is not prescribed 802.1ad (S-Tag) Bridging & with restricted forwarding Support for 1:1 & N:1 VLAN Models Multicast-VLAN Simple Priority based QoS BNG 802.1ad: N:1 & 1:1 support Dual-tag push & pop Auto-sense VLAN (dynamic) & Static VLAN interfaces Hierarchical QoS Modular Multicast Requirements for several deployment scenarios Multicast-VLAN Dynamic H-QoS adjustment PPP or IP for Unicast Single and Dual BNG deployments Security: IP Spoofing  Secure ARP & DHCP Snooping Proxy-ARP CPE (RG) Support of Legacy CPE for Legacy Services RG requirements for new applications/services WT-101 Overview & Status

  21. WT-101 VLAN Architecture Priority is optional. Usually wiser to not change DSL interface

  22. Multicast - Key Attributes • 1) Low Zap time (end user experience <1s, network experience <250ms) • 2) Minimize replication of multicast streams on the core network • 3) No duplication of multicast streams on the access network, • DSL line = low BW, end RG/STB can’t deal with duplicate packets • 4) Redundancy • 5) Ability to migrate to DSLAM IGMP-proxy or RG-Forking at a later stage • 6) Dynamic QoS adjustment on IGMP report • 7) Scale to multiple E320’s connected to M-VLAN (~67K subs for each E320) • 8) DSL Forum - WT-101 compliant

  23. Multicast Solutions –“Like Skinning a Cat!” • 1a: IGMP to M-Series & IGMP-Proxy on E320 • 1b: PIM on M-Series & E320 • 2a: Multicast VR with IGMP-Proxy • 2b: Multicast VR with PIM-SSM • 2c: Only Internet VR with PIM-SSM

  24. WT-101 Multicast Architecture Options Single BNG – PPP – AN/RG Forking 1 Single BNG – IPoE – H-QoS for MC 2 Unicast 1:1 or N:1 1’ Copy IGMP/PPP Msg to IGMP/IPoE on VC Unicast 1:1 or N:1 BNG BNG Deliver IPmc to M-VLAN, update Unicast shaper RG-A Deliver IPmc to M-VLAN, update Unicast shaper RG-A Copy IGMP Msg to M-VLAN & Snoop 2’ Copy IGMP/PPP Msg to IGMP/IPoE on M-VLAN & Snoop M-VLAN IGMP Snooping M-VLAN IGMP Snooping Single BNG – IPoE – no H-QoS for MC 3 Dual BNG – IPoE – no H-QoS for MC 4 Unicast 1:1 or N:1 Unicast 1:1 or N:1 BNG BNG RG-A Deliver IPmc to M-VLAN, don’t update Unicast shaper RG-A M-VLAN IGMP Snooping Copy IGMP Msg to M-VLAN, Snoop & Proxy/Suppress Reports Copy IGMP Msg to M-VLAN, Snoop & Proxy/Suppress Reports Deliver IPmc to M-VLAN, don’t update Unicast shaper M-VLAN IGMP Snooping

  25. Reasons to go for C-VLAN • Faulting / Tracking -> Ethernet OAM immature (Eth-to-ATM OAM even worse) -> C-VLAN allows for ARP broadcast to check end-to-end connectivity • MAC spoofing -> checks/’hacks’ in DSLAMs and switches not considered as secure enough • Multi-session PPPoE -> easier to control • Protocol translation -> MAC@ translation complicates DHCP setups (MAC@ is in DHCP payload as well). L2 DSLAMs require too much complexity • Multicast -> need per-subscriber IGMP knowledge for QoS adjustments • End user id for legal interception -> easier to adapt existing system for ATM to ethernet

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