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Video Storage/Delivery

When Gig Speeds Alone Aren't Enough

Marketing broadband services as "gigabit speed" is a proxy for telling consumers they've got the bandwidth to do whatever they want, as quickly as they want, on the Internet. But what happens when traffic from one application overwhelms throughput capacity so much that even supposed gigabit broadband isn't enough?

File this one in the category of lessons learned the hard way.

According to Wesley Hicks, senior product manager at the testing company EXFO (Nasdaq: EXFO; Toronto: EXF), a network operator customer recently discovered that an OTT video service was having a negative impact on managed IP video delivery. With large amounts of throughput available, the OTT video application was delivering huge chunks of data at a time, making capacity scarce for other services. This bursting behavior meant that the operator's own managed IP video service couldn't access the consistent throughput levels it needed to provide a high-quality video stream.

"We've seen choke points where actually trying to run both services over a gig link, which should be more than enough, [still leads to the OTT service] creating issues with the IPTV, which wants to have that consistent flow," said Hicks, who spoke on a panel at Light Reading's Big Communications Event.

He added that the demands of an OTT service can "cause packet loss right there at the very edge of delivery."

There is a solution to the problem. Namely, an ISP can section off the necessary bandwidth for an IP video service from the amount available to over-the-top Internet applications. However, in the case of the deployment described by Hicks, the operator wasn't creating a virtual LAN for its IPTV traffic, and thus it generated a traffic bottleneck at the network switch leading to its last-mile infrastructure.

So what to do? Implement a VLAN.

But as Hicks points out, implementing a VLAN may require deploying a more expensive switch or router, and as operators push equipment closer to the edge of their networks, they're often looking for cheaper hardware rather than more expensive gear.


Want to learn more about video delivery? Check out our dedicated video services content channel here on Light Reading.


The more network operators roll out gigabit services, the more quirks they and their customers are going to discover that impact performance. Among the obvious ones, delivering gigabit access doesn't ensure that a subscriber's WiFi network can support those high-end speeds, or that a user's computer and other gear can manage the throughput. There's also the issue of latency impacting interactive applications, and applications themselves that may or may not be able to take advantage of higher broadband capacity.

However, there are other factors contributing to performance that aren't as apparent. And as broadband demands continue to rise and network architectures evolve, many of them will only be discovered by trial and error. Plus, those problems will only be solved by measuring the trade-offs between performance and cost.

— Mari Silbey, Senior Editor, Cable/Video, Light Reading

davidhoffman5 5/24/2017 | 9:54:43 AM
Gigabit not enough? I am slightly confused. I thought that GPON delivered 2.4 Gbps down and 1.2 Gbps up raw. Subtract 1/5 for overhead leaving 1.92/0.96 actual content throughput. Take half the down for IPTV, 0.96 Gbps, and the customer is left with a 0.96 Gbps symmetrical WWW internet connection. This is not enough?.
t.bogataj 5/24/2017 | 3:49:06 AM
Re: Net neutrality Duh! & Mari,

the point on net neutrality is not relevant. As long as IPTV or VoIP can (and should!) have different QoS parameters than internet data, setting QoS per OTT is not a matter of "neutrality".

The pricing models (including accounting, billing and data caps) are relevant to decide whether the neutrality is challenged or not -- not the QoS or policing settings. Therefore, if OTT data is properly accounted for, and pricing models are not discriminating, no neutrality issues should occur.

In a wider perspective, it all depends how you define a "service" commercially. If your SP sells you a "classical" triple-play data+TV+voice, then OTT is just part of data. But if you pay for data+TV+voice+OTTapp1+OTTapp2+cloud1+cloud2, then each service has its own price and therefore can (and should!) have its individual QoS parameters. With no net-neutrality challenges.

T.
t.bogataj 5/24/2017 | 3:22:47 AM
App awareness and per-flow QoS The article makes some good points in identifying the problem -- but misses on the proposed solution (or Hicks does) completely. It is sad that the article does not mention that the solution is flow classification and policy enforcement per flow, which allow proper policing and QoS per service/app.

App-aware broadband solutions exist in the market since 2010. Readers may have also noted that, nowadays, this is called software-defined access.

T.
msilbey 5/23/2017 | 4:22:58 PM
Re: Two observations Good point on the net neutrality issue. When and where broadband is actually competitive, there's arguably not much of an issue with sectioning off some bandwidth for a managed TV service and leaving the rest for broadband. However, where broadband service isn't competitive, there's the possibility that ISPs will limit Internet performance in order to divert enough bandwidth to support a managed IPTV offering. 
Duh! 5/23/2017 | 4:11:43 PM
Two observations VLANs are integral to the (x)GPON architecture, so by definition (x)PON OLTs are VLAN-capable. I believe that the same is true for (x)EPON. It's a bit more complicated than that, but no technology impediments come to mind for what he suggests.

OTOH, this is exactly the kind of capability that gets Net Neutrality advocates into a lather. The extent to which that will continue to be a problem in the US is not clear, of course.  Might be a show stopper in Canada, Europe and India.

 
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