Transcript Next Generation BRAS

Truman Boyes
Professional Services APAC
[email protected]
Next Generation
BRAS
Access Technologies for
Consumer Broadband
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
1
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…
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
2
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 1.51.8Mbps for normal TV. 7-9Mbps for HD
compressed.
 HQOS is still extremely important for this
service. It’s enabled on the BNG.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
3
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).
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
4
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.
Video
Head End or
ASP
Single M-VLAN for
video channels
Internet Port
IPTV Port
DSLAM
ASP
(e.g. IP
Telephony)
C-VLAN per
Subscriber
IP Backbone
• RG provides a single VC
connection between home
and DSLAM
• IPoE and 1483B session
(video/IGMP-Proxy)
• Performs
Transparent IGMP
Snooping. MAC
filters and multicast
replication
• IGMP joins received on
subscriber interface
• Adjusts (unicast) VLAN
shaper in QoS hscheduler 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!!!
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
ISP
(Internet)
Enterprise
VPNs
www.juniper.net
5
The second function of IGMP
Dynamic QoS adjustment
5. Unicast Scheduler
(C-VLAN) adjusted
VoIP / VoD
Internet
IPTV
Headend
4. IGMP OIF map to MC-VLAN
3. IGMP/C-VLAN Processed
6. MC Video Session
forwarded over MC
VLAN
2. IGMP
Snooping
1. IGMP
(PPPoE or IPoE)
Copyright © 2005 Juniper Networks, Inc.
7. Final MC
Replication
Proprietary and Confidential
www.juniper.net
6
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.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
7
WT-101: 1:1 VLAN Solution
• 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).
RG
Internet Port
• 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
Multi-Service
BSR
DSLAM
C-VLANs
Optional
Video
Head End or
ASP
ASP
(e.g. IP
Telephony)
IPTV
Switch
IP Backbone
VoIP
• 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
Copyright © 2005 Juniper Networks, Inc.
ISP
(Internet)
Enterprise
VPNs
• Optional: Separate Edge for BIZ
• Same as 1:1 as each port is
directed to a single edge
Proprietary and Confidential
www.juniper.net
8
WT-101: N:1 VLAN Solution
• 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)
RG
Internet Port
IPTV
DSLAM
•
•
•
•
•
•
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
ISP
(Internet)
Service
VLANs
Service Node
with MC
Switch
Switch
VoIP
Business Site
Copyright © 2005 Juniper Networks, Inc.
• 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
Service Node
+ SBC
Video
Head End or
ASP
ASP
(e.g. IP
Telephony)
Service Node
Enterprise
VPNs
Proprietary and Confidential
www.juniper.net
9
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.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
10
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.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
11
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.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
12
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)
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
13
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.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
14
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.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
15
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.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
16
Thank You
APRICOT 06!
[email protected]
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
17
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.
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
18
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:
Copyright © 2005 Juniper Networks, Inc.
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
Proprietary and Confidential
www.juniper.net
19
WT-101 Overview & Status
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
BNG



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

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)


Copyright © 2005 Juniper Networks, Inc.
Support of Legacy CPE for Legacy Services
RG requirements for new applications/services
Proprietary and Confidential
www.juniper.net
20
WT-101 VLAN Architecture
Priority is optional.
Usually wiser to not
change DSL interface
EFM or
ATM Single-VC
S-Tag Arrangements
A
(.1p)
Priority-Tagged
Frames
Residential
Subscribers
(N:1)
Priority-Tagged
Frames
Business or
Residential 1:1
Service 2
101
101
101
101
101
102
101
102
Service 1
101
101
Service 1
Service 2
(.1p)
(.1p)
B
Service 1
(.1p)
Unique C-Tag, Common S-Tag
Access Node
S-Tag Arrangements for N:1 residential:
A – N:1 VLAN scenario where all subscribers are placed into a common VLAN
B – N:1 VLAN scenario where individual subscriber sessions are placed into a common
VLAN based on service type
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
21
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
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
22
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
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
23
WT-101 Multicast Architecture Options
1’ Copy IGMP/PPP Msg to
IGMP/IPoE on VC
1
Unicast
1:1 or N:1
BNG
BNG
RG-A
2’ Copy IGMP/PPP Msg to
IGMP/IPoE on M-VLAN &
Snoop
Deliver IPmc to MVLAN, update Unicast
shaper
M-VLAN
IGMP Snooping
RG-A
Copy IGMP Msg to MVLAN & Snoop
Single BNG – PPP – AN/RG Forking
Deliver IPmc to MVLAN, update
Unicast shaper
M-VLAN
IGMP Snooping
Single BNG – IPoE – H-QoS for MC
3
Unicast
1:1 or N:1
Copy IGMP Msg to MVLAN, Snoop &
Proxy/Suppress
Reports
Deliver IPmc to M-VLAN,
don’t update Unicast
shaper
M-VLAN
IGMP Snooping
Single BNG – IPoE – no H-QoS for MC
Copyright © 2005 Juniper Networks, Inc.
4
Unicast
1:1 or N:1
BNG
RG-A
2
Unicast
1:1 or N:1
BNG
RG-A
Copy IGMP Msg to MVLAN, Snoop &
Proxy/Suppress
Reports
M-VLAN
IGMP Snooping
Deliver IPmc to M-VLAN, don’t
update Unicast shaper
Dual BNG – IPoE – no H-QoS for MC
Proprietary and Confidential
www.juniper.net
24
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
Copyright © 2005 Juniper Networks, Inc.
Proprietary and Confidential
www.juniper.net
25