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Optical/IP

Rethinking B-RAS in an IPTV World?

A new emphasis on video in IP networks may soon demand that service providers and equipment providers take a new look at the role and placement of the Broadband Remote Access Server (B-RAS).

Here's the problem: The B-RAS device is a central aggregation point where service providers accept, authorize, authenticate, and manage Quality of Service (QOS) and policy enforcement for hundreds of thousands of users requesting broadband services. But in the past, the B-RAS was used primarily for broadband data traffic; in an IPTV world, carriers fear the B-RAS may become a bottleneck.

“IPTV is a very bandwidth-sensitive service,” says Jefferies & Co. analyst George Notter. “When the subscriber is watching IPTV and changes the channel, that query cannot go all the way to the central office and back; the risk is that video latency will occur.”

Nothing will inspire the rage of IPTV viewers like screen freezes caused by network snags. After all, we might be talking about the season finale of Desperate Housewives here -- the stakes are that high.

The B-RAS traditionally has resided at the edge of the service provider’s core network, but service providers are increasingly moving that functionality outward, away from the core, Notter says.

“You’re starting to see different approaches emerging around B-RAS. Carriers would rather have the B-RAS in the central office, but in the future the B-RAS will move closer and closer to the customer,” Notter says.

There is considerable debate among service providers and equipment vendors on the issue. The vendors fire their salvos through white papers and new product feature sets.

Redback Networks Inc. (Nasdaq: RBAK), for instance, will tell you that the B-RAS should reside just behind the DSLAM at the local office, while others are vocal about their preference for placing the B-RAS closer to the central office.

The service providers, meanwhile, speak through their RFPs.

BellSouth Corp. (NYSE: BLS) released its RFP for a new IPTV network last August, and the RFP both states the architectural philosophy of the RBOC, and serves as a call out to vendors to provide equipment to facilitate those ideas.

With regard to broadcast TV streaming using IP multicast, BellSouth may deal with the B-RAS bandwidth issue by not dealing with it.

“The role of the B-RAS in BellSouth’s IPTV network will probably not include a lot of video,” says Heavy Reading analyst Graham Beniston. “They want to keep lots of B-RAS capability, but they see they need much more bandwidth for high percentage usage of video on demand.”

Beniston says the BellSouth RFP may be a sort of challenge to the vendor community to come up with better answers. “I think they are throwing the challenge to the B-RAS vendors: ‘Can you handle it? Well, can you?’”

For example, the RFP suggests BellSouth may spread some B-RAS functionality over several boxes in its fiber-to-the-curb (FTTC) network. Some B-RAS capability may reside in hardened units under the street (close to the subscriber), Beniston said. Vendors, presumably, will have to address such ideas in material terms in their proposals, or suggest something better.

If the role of B-RAS in IPTV is just now being worked out in this way, what implication does this hold for the future health of B-RAS equipment vendors?

Beniston says it is neutral for vendors already entrenched in the market, while it may be bad tidings for smaller vendors trying to break in. Overall, the B-RAS market will continue to grow “moderately” because the need for B-RAS aggregation of data traffic alone is still growing, he says.

The Yankee Group sees evidence of this growth in the spate of B-RAS RFPs worldwide, leading to their conclusion that the global B-RAS market will grow at a five-year compound annual growth rate of 25 percent from 2003 to 2008, when it will exceed $1 billion.

BellSouth said in August, when it released the IPTV RFP, it would announce a winner in the next three months. The odds-on favorite to win, according to several sources, is DSLAM incumbent Alcatel SA (NYSE: ALA; Paris: CGEP:PA).

— Mark Sullivan, Reporter, Light Reading

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iponthebrain 12/5/2012 | 3:29:30 AM
re: Rethinking B-RAS in an IPTV World? Why would you need a BRAS for IPTV? You just need a router that supports VPLS.
paolo.franzoi 12/5/2012 | 3:29:29 AM
re: Rethinking B-RAS in an IPTV World?
First off, TR-58 and 59 are wholly deficient in a IPTV world. Thus, cometh WT-101 as a replacement to be able to handle the problem. Which basically stated is this:

"In TR-58/59, the basic assumption was that the DSLAM is an unblocked element of the network. Given Video Traffic and other potential premium services this is no longer true."

Secondarily, most of the BRAS implementations do not have the forwarding plane throughput to be able to handle video traffic (yes, you go run every port of your router at wirespeed forever and see what happens).

Finally, there is a massive control plane issue hanging over all of this. Having 3/channel changes a sec per subscriber show up at the router at the top of the hour (as people channel surf) is going to put tremendous loads on the BRAS control planes (could be a maximum of 100,000 control plane messages a second). Wait, we will proxy the IGMP messages. Hold on, then the BRAS will lose what is going on at a DSL port. Rather a sticky wicket eh? Oh, thats right we are all changing our viewing patterns tomorrow so this will not be an issue.

seven
iponthebrain 12/5/2012 | 3:29:28 AM
re: Rethinking B-RAS in an IPTV World? As I understand, the IGMP ad VPLS function will be integrated into the DSLAM where you only have to deal with about 600 subscribers each. At 2 non HD and 2 HD channels per subscribers, the routing horsepower demand should be less than if you centralized it. Also, if you centralized it, the backhaul and delay issue would be prohibitive. Again, this eliminates the need for an edge router or traditional BRAS.
Dredgie 12/5/2012 | 3:29:26 AM
re: Rethinking B-RAS in an IPTV World? Do you need a BRAS? Yes and no. DSLF WT-101 (referenced by brookseven) suggests 2 content injection points - network gateways / services nodes. One for video and the second for all other (ISP/ASP) application, services and content. For the latter, a carrier could go to a policy based router model (PBR) favored by the MSOG«÷s, but they love their PPP and L2TP! Hence, one of the two being defined (i.e. the G«ˇBRASG«÷ one - as opposed to the video one) would continue to support a familiar G«ˇBRASG«÷ feature-set. The other, as you suggest, would be basically a router. (The terms G«ˇfamiliarG«÷ and G«ˇbasicallyG«÷ are used tenuously here, as the whole area of multicast and VLAN usage throws proverbial spanners into the works). The tricky part is tying the two together when trying to perform session-level on demand bandwidth and QoS on the last mile. But thatG«÷s another topic.
paolo.franzoi 12/5/2012 | 3:29:19 AM
re: Rethinking B-RAS in an IPTV World?
Well you need someone to define the bandwidth subscription and you can call it anything you want. However, nobody is going to build it into DSLAMs:

1 - There are LOTS of DSLAMs so people will be paying for this intelligence.

2 - The management of so many devices will swamp operations folks.

So, IGMP will not be terminated on the DSLAMs just snooped. DSLAMs will not have a control plane to deal with Unicast traffic like VoD or any other premium (read paid for and therefore better work) services.

Basically, you don't put 45,000 control points in a network if you can get away with 450. And you don't shove all this heavy lifting down to sub-$50/port devices. Not going to happen.

seven
iponthebrain 12/5/2012 | 3:29:18 AM
re: Rethinking B-RAS in an IPTV World? Seven,

"Well you need someone to define the bandwidth subscription and you can call it anything you want. However, nobody is going to build it into DSLAMs"

Understand your perspective but times have changed. Already built-in....

http://www.alcatel.com/product...

The Alcatel 7302 ISAM is a key step in Alcatel's strategy to enable user-centric broadband services. Its unique IP features allow operators to bring service intelligence in the network closer to the user. This will allow them to ensure a better user experience, faster new service initialization and effective service networking as part of the end-to-end Alcatel IP solution.

Intelligent service forwarding modes for secure deployment of broadband services over Ethernet aggregation through centralized broadband remote access server (BRAS) or distributed service edge (point-to-point protocol termination in the DSLAM, DHCP Relay, etc.).
paolo.franzoi 12/5/2012 | 3:29:17 AM
re: Rethinking B-RAS in an IPTV World?
Guess what, that is all nice.....take a read of how its going to be deployed at SBC and BLS. None of that will be turned on.

seven
OldPOTS 12/5/2012 | 3:29:16 AM
re: Rethinking B-RAS in an IPTV World? brookseven wrote;
Guess what, that is all nice.....take a read of how its going to be deployed at SBC and BLS. None of that will be turned on.
-----------------------------------

Got an URL that I can Read on how it is going to be deployed? To DSLAM & FTTU

OldPOTS
Dindon 12/5/2012 | 12:58:28 AM
re: Rethinking B-RAS in an IPTV World? DSL Forum already issued some TRs that talks about dynamic service and how to manage two way QoS.

Would suggest read TR59 and TR69...

Many vendors already published that their products support these specifications.
Dindon 12/5/2012 | 12:58:27 AM
re: Rethinking B-RAS in an IPTV World? Take a look at http://www.juniper.net/company...

Alcatel has any B-RAS? They only have DSLAM and is trying to maximize some features to charge more than plain DSLAM from Huawei...

In my opnion the only Broadband Service Router, known as B-RAS when had only PPPoE authentication, capable to support QoS, Jitter and latency control is Juniper's ERX.

Not talking about how to secure the IP Setup box and IP Phone from attacks... think about that how to secure the IP Eletronic devices at home broadband...
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