Video: Monolithic and Spine-Leaf Architectures

It’s hard to talk about SMPTE 2110 system design without hearing the term ‘spine and leaf’. It’s a fundamental decision that needs to be made early on in the project; how many switches will you use and how will they be interconnected? Deciding is not without accepting compromises, so what needs to be considered?

Chris Lapp from Diversified shares his experience in designing such systems. Monolithic design has a single switch at the centre of the network with everything connected directly to it. For redundancy, this is normally complemented by a separate, identical switch providing a second network. For networks which are likely to need to scale, monolithic designs can add a hurdle to expansion once they get full. Also, if there are many ‘low bandwidth’ devices, it may not be cost-effective to attach them. For instance, if your central switch has many 40Gbps ports, it’s a waste to use many to connect to 1Gbps devices such as audio endpoints.

The answer to these problems is spine and leaf. Chris explains that this is more resilient to failure and allows easy scaling whilst retaining a non-blocking network. These improvements come at a price, naturally. Firstly, it does cost more and secondly, there is. added complexity. In a large facility with endpoints spread out, spine and leaf may be the only sensible option. However, Chris explores a cheaper version of spine and leaf often called ‘hub and spoke’ or ‘hybrid’.

If you are interested in this topic, listen to last week’s video from Arista’s Gerard Philips which talked in more detail about network design covering the pros and cons of spine and leaf, control using IGMP and SDN, PTP design amongst other topics. Read more here.

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Chris Lapp Chris Lapp
Project Engineer, SME Routing
Wes Simpson Wes Simpson
President, Telcom Product Consulting

Video: International IP Production Networks

Optical Transport Networking (OTN) is a telco-grade technology which simplifies the transport of high-bandwidth data such as uncompressed video. Taking the place of SDH and Ethernet, OTN is an ITU-created recommendation called G.709 which dates back to 2009. With OTN, transport and decoding of multiple signals are simplified with the ability to carry many different data types including SDH and Ethernet.

Telstra’s Steven Dargham joins the VSF’s summer sessions to explain why Telstra has created an international network for live broadcast production based on OTN and to discusses some case studies. Using SMPTE ST 2110-20 and -22, Telstra as seen that remote production can be done without so much equipment at the game.

Steven takes some time to outline the Latency-Bandwidth-Quality triangle where one of these will always suffer at the expense of another or both the others. Understanding this balance and compromise leads to understanding the choice of video codec to use such as TICO, VC-2, JPEG XS etc. Steve talks through a table showing the pros and cons of the codecs available to chose from.

The video ends with Steven talking us through case studies on moving Telco between Japan and UK, their work for the IAAF Athletics using these to explain why they are able to keep AWS ingo.

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Steven Dargham

Video: Hybrid SDI/ST 2110 Workflows

It’s no secret that SDI is still the way to go for some new installations. For all the valid interest in SMPTE’s ST 2110, the cost savings are only realised either on a large scale or in the case that a system needs continuous flexibility (such as an OB truck) or scalability in the future. Those installations which have gone IP still have some SDI lying around somewhere. Currently, there are few situations where there is an absolute ‘no SDI’ policy because there are few business cases which can afford it.

Looking at the current deployments of broadcast 2110, we have large, often public, broadcasters who are undergoing a tech refresh for a building and can’t justify such as massive investment in SDI or they are aiming to achieve specific savings such as Discovery’s Eurosport Transformation Project which is an inspirational, international project to do remote production for whole buildings. We also have OB trucks who benefit significantly from reduced cabling, higher density routing and flexibility. For a more detailed view on 2110 in trucks, watch this video from NEP. In these scenarios, there is nearly always SDI still involved. Some equipment doesn’t yet work fully in 2110, some doesn’t yet work at all and while there are IP versions of some products, the freelance community still needs to learn how to use the new products or work in the new workflows. If you have a big enough project, you’ll hit the ‘vendor not yet ready’ problem, if you have an OB-truck or similar, you are likely to have to deal with the freelance experience issue. Both are reducing, but are still real and need to be dealt with.

Kevin Salvidge from Leader joins the VSF’s Wes Simpson to share his experience of these SDI/IP mixed workflows, many of which are in OB trucks so also include mixed HDR workflows. He starts by talking about PTP and GPS discussing how timing needs to be synced between locations. He then takes a closer look at the job of the camera shaders who make sure all the cameras have the same colour, exposure etc. Kevin talks about how live production in HDR and SDR work touching on the problem of ‘immediacy’. Shaders need to swap between cameras quickly and are used to the immediate switch that SDI can provide. IP can’t offer quite the same immediacy, Kevin says that some providers have added delays into the SDI switches to match the IP switch times within the same truck. This helps set expectations and stop operators pressing two or more times to get a switch made.

Kevin finishes his talk on the topic of synchronising analogue timing signals with PTP. Kevin shows us the different tools you can use to monitor these signals such as a display of PTP timing against B&B timing, a BMCA data readout of data from the PTP grandmasters to check if the BMCA algorithm is working correctly, PTP delay time, packet inter-arrival time, path delay, traffic shaping monitoring. He then closes with a Q&A talking about the continued prevalence of SDI, what ‘eye patterns’ are in the IP world and increasing HDR roll-outs.

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Kevin Slavidge
European Regional Development Manager
Leader Europe Ltd.
Wes Simpson Moderator: Wes Simpson
President, Telcom Product Consulting

Video: The 2020 EBU Pyramid of User Requirements

There’s a lot more to IP-based production than just getting your video and audio streaming between devices. You need configuration tools, you need timing, there’s the management of the devices to consider and, critically, security. the problem is, working in IP is still new and many of the solutions are yet to mature. This means we still don’t have all the tools we need to realise the full promise of live production IP systems.

Back in 2018, the EBU embarked on a project to focus the industry on the gaps: The Technology Pyramid. This pyramid shows that although we, as an industry, had largely succeeded in defining essence transport over IP, this was only the ‘top of the iceberg’, so to speak, in what needed to be done. also known by its full name, “The Technology Pyramid for Media Nodes 2018”, it shows that everything is underpinned by security, upon that is configuration and monitoring, with discovery and registration built on that.

One important aspect of the pyramid is the green – yellow – red colour coding. When initially released, the only green was the transport layer, but this talk looks at the 2020 edition of the pyramid which shows that the time & sync, as well as discovery and connection, have improved.

We’re joined by Willem Vermost and Félix Poulin to discuss the problems the industry has faced to date and the progress made in making the pyramid green. Both previously with the EBU and now both with early-adopter broadcasters who are going live with IP systems, they are perfectly placed to explain the evolution on of the market.

Not only has the colouring of the pyramid changed, but the detail of what each layer constitutes has evolved. The industry has reacted with a number of specifications such as JT-NM TR-1001-1 and AMWA BCP-003. Willem and Félix explain the hidden necessities that have come out of the woodwork as the early adopters have fought to make everything work. PTP is a good example, being able to free-wheel without a PTP clock for 5 minutes and then join back without a glitch has been added to the list of requirements. Time stamping and lip-sync have proven tricky, too. Intermediate processing steps place their timestamps over the original timestamp of when the media was captured. If you are trying to sync audio and video which have gone through processing, you need the original timestamps which have now been lost. This problem is being addressed but until it is, it’s a big gap.

Overall we can see the power of focussing people’s attention in this way. Whilst there is much more detail in the talk itself, just from the extracts in this article, it’s clear progress has been made and with plenty more broadcasters starting their IP projects, there is all the more motivation for the vendors to implement the requirements as laid out than there was before.

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Willem Vermost Willem Vermost
Design & Engineering Manager,
Félix Poulin Félix Poulin
Direcor – Media Transport Architecture & Lab