Hi danversj,

You make some good points.

To be clear, I'm not at all critical of anyone who brings discussion to the public sphere with the intention of simply advancing knowledge. You describe that as your intention and I think that is very noble. Your substantive knowledge of the subject matter is excellent and I believe the discussion is very well suited to forums like these.

The SMPTE submission changes things a little for me. From a commercial perspective, when I pay the significant costs to attend the seminars at SMPTE, I expect (I think reasonably) a certain level of quality in the information I'm paying for. I expect to receive information that is concrete, not rubbery; information above and beyond what is freely available on the internet; information that is properly synthesized; and a presentation free of terminology flubs. If you had paid over $1,000 for an audience seat to gather information that hopefully gives you a leading edge in the market, I think you would expect the same. For this reason, I am always very cautious about publishers and professional bodies that want to charge for access to my work. Attaching a price tag to information tends to imply a warranty for a certain level of quality. Your employer also endorsed the quality of your work by attaching their masthead and logo to the presentation. In my mind, both these things open up your work to a level of scrutiny and criticism beyond what would be fair in a healthy forum discussion. Do you agree?

You might have missed my point on the cost comparisons. At the outset, I indicated agreement that convergence into networking is almost certain. My point is that you're comparing the cost of an SDI router with a laser module. That module is like a backplane on a DA, it needs to fit into a network switch. A very, very fast one. To replace the signal distribution such as that used by your employer now (can I assume that HD1 has around 300 DA's and a 576-sq router?) you need an ethernet core switch capable of somewhere between 10-20 Tbps switching throughput. The cost of laser transceivers pales into insignifcance next to the costs for a core switch that big. They do exist though; the newest range of carrier-grade switches would be fast enough to fully replace the distribution infrastructure in a truck with 300 DA's and a 576-sq router. But the costs are wholly different to what's described in your paper, which is my point. When comparing costs, I think it's important to compare apples with apples. Would you agree? The items in table 2 are not interchangeable with the items in table 1 in your paper. Or am I missing something?

I take your point that there are still aspects (latency, QOS, etc) that need more teasing out. My personal opinion is that proper provisioning of bandwdith will overcome the need for QOS and queuing mechanisms. QOS is only useful in situations where the traffic exceeds the available bandwidth. I also think that SMPTE 2022-6 will answer a lot of the other problems. But that's just my own opinion. I give it to you for free - so it doesn't come with any warranties about quality.

Thanks for the feedback! Will you be at this months SMPTE meeting at CSIRO?

P.S. If you're serious about examining the topic in detail, have you considered enrolling in a uni research program? Having your research supervised by a uni guarantees the protection of information to some extent, so many organisations are quite happy to furnish you with sensitive information about equipment age, upgrade roadmaps, etc. Tutors will teach you how to tap into the research and resources you see as inaccessible at the moment. You'll also have access to vast library resources (think Google Scholar) and your paper will be scrutinised by professional examiners to ensure it is defensible and robust before being released to the public. Something to think about.

This article makes for an interesting forum discussion. But it's poor quality in its original intention. It was presented at a leading Australian trade show where participants paid upwards of $1,000 to attend. It was subsequently published in an Australian trade magazine.

My issue with this article is that it does little to advance knowledge. It presents no new or original research, or even much insight. It's basic premise can be reduced down to "...it should be possible to one day replace all circuit-switched video systems with packet-switched networks." If I presented that argument to any one of my professional peers in the workplace, I would anticipate a response of, "Yeah.... and?"

For many, it is a given that broadcast systems will eventually converge on traditional networks. It happened to telephony, book libraries, and even social media. Why would silicon manufacturers such as Xilinx be marketing brand new chipsets like as the Virtex-6 for encapsulating 3G-SDI into IP if there wasn't any application for it? Why would the Standards Committee at SMPTE be working to ratify the rules of engagement on SMPTE2022-6? Why would Cisco be rushing new variants of the DCM to market that can encapsulate full video streams at baseband data rates?

"It should be possible to replace circuit-switched video platforms with packet-switched networks one day." No sh*t, Sherlock. I might as well throw in there for good measure that it should be possible to one day fly to work using a rocket-propelled backpack. What the industry really needs is some insight into the economics driving such a change, and some well-informed models and timelines on transition and implementation - you know, the types of data grounded in solid research that platform operators can actually use to plan upon.

Discussing the reliability of IP networks for mission-critical applications is simply a waste of everyone's time. IP networks are already being used in much more fail-sensitive applications like stock markets, medicine and defence. Why don't we just assume that reliability under good engineering practices is well proven and move on? The same goes for real-time applications. IP delivers delay sensitive communications for voice and video already. Problems with latency and system timing for video are already ironed out in MPEG-on-IP stacks and full frame rate videoconferencing.

The economic comparisons presented in this paper are mind-boggling. From what I can see, Table 1 and Table 2 compare the cost of contemporary broadcast equipment with the cost of various laser transceiver modules (SFP and XFP). These items are about as interchangeable as a bullet and a warship. They will still be equally as un-interchangeable when 2015 rolls around and breaths life into Table 3. What are you trying to tell us? You've contrasted the current cost of a video router with the forecast cost of a laser transceiver - what can I conclude from this?

Why don't you try a more useful comparison, like contrasting the cost of contemporary SDI distribution with the equivalent ethernet-based distribution. Take a medium-sized broadcast plant that has a 576-square router and 300 distribution amplifiers. This computes to a total of 3,976 video flows. For 1080p, you would need a switch fabric that can sustain 11.9 Tbps of non-redundant throughput (plus overheads and other traffic). The good news is that such beasts do exist. Wheel in the Cisco Nexus 7000. It's designed as a carrier-grade backbone switch, and it's fast. BSkyB use it for core switching in the Harlequin building. It can provide 768x 10Gbps ports and a total fabric throughput of 17.6 Tbps. It is a real subsititute for an SDI router and ten frames of DA's, and you can buy one right now. You'll probably want two though, for redundancy. Allow a million dollars each, plus spares and support and you'll be in the ballpark. The total solution is still 4-5 times the price of an SDI router and DA frames, before purchasing a single camera, monitor, processor or piece of glue to plug into it. Now apply Moore's law (or whatever the relevant prevailing trend rates are for affordability of networks) and you might be able to tell us when ethernet-based technology might be on-par with SDI infrastructure.

Any good analysis should factor support, administration and labour into cost models. If the authors believes that building, timing and maintaining a broadcast video system is complex, they should try constructing a switch fabric with more than 3,000 multicast trees, 10 Tbps data, complex routing protocols, rapid per VLAN spanning tree, and deterministic path-switching. You'll need to attract all these expertise away from SME's working in top network engineering positions at tier one telco's, cable operators and ISP's, before you can even start training your permanent staff. And Global think the freelance market is expensive now? Ohh, boy.

But I diverge. My point is this - when I look at papers from technology innovators like Dell and IBM, I see sound arguments based on sound logic and research leading to agreeable conclusions. This paper was presented by a top engineer who works for Australia's leading provider of OB managed services to Australia's premiere broadcast conference where some participants pay a lot of information and market insight. All I see disjointed arguments, a bit of light commentary on contemporary practice and some superficial speculation that doesn't dig much deeper than what connectors might be seen on the back of boxes some unknown time in the future. Critical reasoning and an appreciation for the value of information seem lost to me.

And the guys at SMPTE wonder why less people turn up at the conferences each year.

Ohh well..

P.S. At the risk of being pedantic - if you are going to talk about Ethernet with any degree of credibility at a seminar where participants pay considerably to attend, please take a moment to review the OSI model and understand the differences between packets and frames. Ethernet is not a packet-switching network architecture. The appropriate PDU at layer 2 is a frame. Ethernet is a frame-switching network architecture.