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Truman Boyes Professional Services APAC [email protected]. 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? - PowerPoint PPT PresentationTRANSCRIPT
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Next Generation BRAS
Access Technologies for Consumer Broadband
Truman BoyesProfessional Services APAC
2Copyright © 2005 Juniper Networks, Inc. Proprietary and Confidential www.juniper.net
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…
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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.
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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).
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Multicast - Overview
IP Backbone
• Performs Transparent IGMP Snooping. MAC filters and multicast replication
Internet Port
IPTV Port
Single M-VLAN for video channels
• RG provides a single VC connection between home and DSLAM
• IPoE and 1483B session (video/IGMP-Proxy)
VideoHead End or
ASP
ASP(e.g. IP
Telephony)
ISP(Internet)
EnterpriseVPNs
• IGMP joins received on subscriber interface
• Adjusts (unicast) VLAN shaper in QoS h-scheduler to reflect MC traffic
C-VLAN per Subscriber
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!!!
• 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.
DSLAM
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The second function of IGMPDynamic QoS adjustment
Subscriber V
C
Multicast V
LAN
Subscriber V
LAN
3. IGMP/C-VLAN Processed
IPTVHeadendInternet
VoIP / VoD
1. IGMP(PPPoE or IPoE)
2. IGMPSnooping
5. Unicast Scheduler (C-VLAN) adjusted
7. Final MC Replication
6. MC Video Session forwarded over MC
VLAN
4. IGMP OIF map to MC-VLAN
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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.
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WT-101: 1:1 VLAN Solution
IP Backbone
Internet Port
IPTV
Multi-ServiceBSRRG
VideoHead End or
ASP
DSLAMC-VLANs ASP
(e.g. IP Telephony)
ISP(Internet)
EnterpriseVPNs
• 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
VoIP
Switch
• 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).
• 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
• Optional: Separate Edge for BIZ• Same as 1:1 as each port is
directed to a single edge
Optional
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WT-101: N:1 VLAN Solution
Internet Port
IPTV
RG VideoHead End or
ASP
DSLAMService VLANs
ASP(e.g. IP
Telephony)
ISP(Internet)
EnterpriseVPNs
• 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)
VoIP
SwitchSwitch
Business Site
Service Node with MC
Service Node+ SBC
BRAS
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
• 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
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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.
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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.
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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.
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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)
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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.
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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.
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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.
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Thank You APRICOT [email protected]
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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.
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WT-101 BackgroundWT-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
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WT-101 Overview & StatusAccess 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
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WT-101 VLAN Architecture
Priority-Tagged Frames
101 101
S-Tag Arrangements
ResidentialSubscribers
(N:1)
A B
Access Node
EFM or ATM Single-VC
101101
101102
101101
101102
Service 1
Service 2
Service 1Service 2
Service 1
(.1p)
(.1p)
(.1p)
(.1p)Business orResidential 1:1
Unique C-Tag, Common S-Tag
S-Tag Arrangements for N:1 residential:
A – N:1 VLAN scenario where all subscribers are placed into a common VLANB – N:1 VLAN scenario where individual subscriber sessions are placed into a common
VLAN based on service type
Priority-Tagged Frames
Priority is optional. Usually wiser to not change DSL interface
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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
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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
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Single BNG – PPP – AN/RG Forking Single BNG – IPoE – H-QoS for MC
Dual BNG – IPoE – no H-QoS for MCSingle BNG – IPoE – no H-QoS for MC
WT-101 Multicast Architecture Options
BNG
RG-A2’ Copy IGMP/PPP Msg to IGMP/IPoE on M-VLAN & Snoop
1’ Copy IGMP/PPP Msg to IGMP/IPoE on VC
Unicast1:1 or N:1
M-VLANIGMP Snooping
Deliver IPmc to M-VLAN, update Unicast shaper
BNG
RG-A
Unicast1:1 or N:1
M-VLANIGMP Snooping
Deliver IPmc to M-VLAN, update Unicast shaper
Copy IGMP Msg to M-VLAN & Snoop
BNG
RG-A
Unicast1:1 or N:1
M-VLANIGMP Snooping
Deliver IPmc to M-VLAN, don’t update Unicast shaper
Copy IGMP Msg to M-VLAN, Snoop & Proxy/Suppress Reports
BNGRG-A
Unicast1:1 or N:1
M-VLAN IGMP Snooping
Copy IGMP Msg to M-VLAN, Snoop & Proxy/Suppress Reports
Deliver IPmc to M-VLAN, don’t update Unicast shaper
1 2
3 4
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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